IL254374B - Device for detecting ice - Google Patents
Device for detecting iceInfo
- Publication number
- IL254374B IL254374B IL254374A IL25437417A IL254374B IL 254374 B IL254374 B IL 254374B IL 254374 A IL254374 A IL 254374A IL 25437417 A IL25437417 A IL 25437417A IL 254374 B IL254374 B IL 254374B
- Authority
- IL
- Israel
- Prior art keywords
- optical
- radiation
- control volume
- detector
- ice
- Prior art date
Links
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64D15/00—De-icing or preventing icing on exterior surfaces of aircraft
- B64D15/20—Means for detecting icing or initiating de-icing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64D45/00—Aircraft indicators or protectors not otherwise provided for
Landscapes
- Engineering & Computer Science (AREA)
- Aviation & Aerospace Engineering (AREA)
- Power Steering Mechanism (AREA)
Description
DEVICE FOR DETECTING ICE TECHNOLOGICAL FIELD The presently disclosed subject matter relates to icing detectors, particularly for aircraft.
BACKGROUND ART References considered to be relevant as background to the presently disclosed subject matter are listed below:- US 5823474- US 9013332- US 6010095- US 5296853- US 5551288- WO 2015/114624- US 4553137- US 6206325- US 2011/067726- DE 102011102804- WO 2010/006946- US 2007/176049- US 2008/110254- US 5400144- US 2014/263260- US 2012/274938- US 5760711- US 4461178- GB 1364845- US 5191791- US 2013/175396 024906188-05 US 8060334US 2004/036630US 2002/158768US 2012/193477GB 563148US 2004/231410US 6091335US 5484121US 4797660US 2010/110431US 4681450US 8060334US 6206325US 2011/067726US 2012/036826DE 102011102804WO 2010/006946DE 2624801US 2009/055036GB 1561979GB 765802WO 2011/003963US 2681409US 2229740US 2015/115053CN 105369334FR 1270264JP 2010029573JP 2011110210US 2002/178493JP 2001329600 024906188-05 - AN OVERVIEW OF THE DEICING AND ANTIICING TECHNOLOGIES WITH PROSPECTS FOR THE FUTURE, 20(http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.476.6317&rep=rep 1&type=pdf).- A new technology De-Ice Anti Ice Proposal (http://www.iasa- intl.com/folders/belfast/laissez-faire.html)- ICE CAT Aircraft Deicing System, 20(http://www.trimacsvstems.com/icecat.php)Acknowledgement of the above references herein is not to be inferred as meaning that these are in any way relevant to the patentability of the presently disclosed subject matter.
BACKGROUND Ice buildup on aircraft, in particular on their aerodynamic lift and control surfaces, can seriously affect the performance and control of the aircraft, sometimes leading to the loss of lift and/or control, and thus of the aircraft.
Ice detectors are often used for the detection of ice buildup, and such detectors have been in use for many years. Such ice detectors can be based on a range of operating principles.
By way of non-limiting example, US 6,010,095 provides an icing detector for detecting presence of both rime ice and clear ice in air comprising an ice collecting surface facing an oncoming air stream; light emitting apparatus for emitting a light beam crossing the ice collecting surface, having a prismatic light refracting window for refracting the light beam in a first direction, when no ice is present on the ice collecting surface; light sensing apparatus in a path of the second direction, and annunciating apparatus coupled to the light sensing apparatus for annunciating presence of ice when light is sensed by the light sensing apparatus.
Also by way of non-limiting example, GB 563,148 discloses an ice-formation detector, enclosed behind the leading edge 6 of an aircraft wing, and comprises a metal chamber 5 having at its forward end a disc 7 of perforated metal to admit pressure air024906188-05 into the chamber during flight, a connection pipe 19 leading to a low-pressure area such as the underside of the wing trailing edge being provided of suitable bore to allow escape of pressure air from the chamber 5 at such a rate that during flight under nonicing conditions there will be maintained a pressure within the chamber which is high enough to act upon a resilient diaphragm 9, covering a hole in the chamber wall, so as to keep separated spring controlled electrical contacts 14, 15. According to this publication, when icing takes place so as to occlude perforations of disc 7 reduction of pressure occurs in the chamber so that contacts 14, 15 are brought together to complete the circuit of an indicator and/or of de-icing means for the disc 7 and other de-icing means such as 6b within the wing structure.
GENERAL DESCRIPTION According to a first aspect of the presently disclosed subject matter, there is provided a device for detecting presence of ice in an airstream, comprising:- body defining an ice accretion control volume facing the airstream;- at least one first electromagnetic (EM) transmitter configured for transmitting EM radiation, at least one first EM detector configured for detecting said EM radiation, and at least one second EM detector configured for detecting said EM radiation, said at least one first EM detector being different from said at least one second EM detector;- the device providing a first optical path for said EM radiation from said first EM transmitter to said at least one first detector in the absence of ice in said control volume;- the device further providing a second optical path for said EM radiation to said at least one second detector in the presence of ice in said control volume, said second optical path being different from said first optical path.
According to the first aspect of the presently disclosed subject matter, the device can include one or more of the following features. 024906188-05 For example, the body defines a reference axis associated with the control volume, the reference axis being generally transverse to the airstream.
Additionally or alternatively, said EM radiation is in at least one of the visible spectrum, ultraviolet (UV) spectrum, infrared (IR) spectrum.
Additionally or alternatively, for example, said EM radiation has a radiation wavelength of wavelength 650nm or 980nm.
Additionally or alternatively, for example, said control volume is defined by a cutout portion in said body, said cut-out portion comprising an accretion surface facing the airstream connected at one axial end thereof to a first end wall and at another axial end thereof to a second end wall.
For example, said reference axis intersects said first end wall and said second end wall..
Additionally or alternatively, for example, said at least one first EM transmitter comprises an optical refracting component. For example, said optical refracting component comprises a prismatic element having a prism apex angle of 30°.
Additionally or alternatively, for example, said at least one first EM transmitter comprises a respective at least one first optical fiber element for transmitting said EM radiation along a respective first optical fiber axis.
Additionally or alternatively, for example, said at least one first EM transmitter comprises a respective at least one first optical fiber element for transmitting said EM radiation along a respective first optical fiber axis, and wherein said optical refracting component is integral with at a free end of said least one first optical fiber.
Additionally or alternatively, for example, said optical refracting component is in the form of an optical prism. Alternatively, said optical refracting component is in the form of an optical prism; for example, the device further comprises a first optical folding component in optical communication with said optical refracting component and said at least one first optical fiber element. 024906188-05 Additionally or alternatively, for example, said optical refracting component comprises an optical output surface generally facing towards said second end wall. For example, said optical output surface is tilted with respect to said reference axis such that said first optical path and said second optical path are on different sides with respect to said reference axis.
Additionally or alternatively, for example, said at least one second EM detector comprises a respective at least one second optical fiber element for detecting said EM radiation along a respective second optical fiber axis.
Additionally or alternatively, for example, said at least one first EM detector comprises a respective at least one third optical fiber element for detecting said EM radiation along a respective third optical fiber axis.
Additionally or alternatively, for example, the device further comprises at least one backscatter EM detector for detecting backscatter radiation originating from said EM radiation within said control volume. For example, said at least one backscatter EM detector comprises a respective at least one fourth optical fiber element for detecting said backscatter radiation along a respective third optical fiber axis.
Additionally or alternatively, for example, in one example said at least one first EM transmitter is configured for transmitting said EM radiation from said first end wall towards said second end wall, wherein said at least one first EM detector is configured for detecting said EM radiation at a respective first location on said first end wall, and wherein said at least one second EM detector is configured for detecting said EM radiation at a respective second location on said first end wall, said first location being different from said second location. For example, said second end wall comprises a first reflection surface and a second reflection surface, said first reflection surface being configured for reflecting said EM radiation incident thereon from said first EM transmitter towards said at least one first EM detector in the presence of air in said control volume, and said second reflection surface being configured for reflecting said EM radiation incident thereon from said first EM transmitter towards said at least one second EM detector in the presence of ice in said control volume. 024906188-05 Alternatively, for example, in another example said at least one first EM transmitter is configured for transmitting said EM radiation from said first end wall towards said second end wall, wherein said at least one first EM detector is configured for detecting said EM radiation at a respective first location on said second end wall, and wherein said at least one second EM detector is configured for detecting said EM radiation at a respective second location on said second end wall, said first location being different from said second location. For example, said second end wall comprises a first optical input surface at said first location, and a second optical input surface at said second location, said first optical input surface operating to channel said EM radiation incident thereon from said first EM transmitter towards said at least one first EM detector in the presence of air in said control volume, and said second optical input surface operating to channel said EM radiation incident thereon from said first EM transmitter towards said at least one second EM detector in the presence of ice in said control volume. Additionally or alternatively, for example, the device further comprises at least one electromagnetic (EM) system that is configured for transmitting EM energy to said control volume, said EM energy being configured for melting ice that can accrete within said control volume in operation of the device. For example, said EM system is configured for providing laser energy of wavelength in the range of 1470nm to about 1550nm, for example: about 1470nm, or about 1500nm, or about 1550nm. Additionally or alternatively, for example, said EM system is configured for providing laser energy of intensity between 0.01 W/mm2 and 0.1 W/mm2. Additionally or alternatively, for example, said EM system is configured for providing laser energy of intensity 0.03 W/mm2.
Additionally or alternatively, for example, said EM system is further configured for directing said laser energy toward said second end wall.
Additionally or alternatively, for example, said EM system is configured for directing said laser energy toward along a transmittal direction generally parallel to said reference axis.
Additionally or alternatively, for example, said EM system is configured for directing said laser energy toward along a transmittal direction generally orthogonal to said reference axis. 024906188-05 Additionally or alternatively, for example, said EM system is configured for directing said laser energy toward along a transmittal direction towards said control volume having first traversed said accretion surface.
Additionally or alternatively, for example, said EM system is further configured for directing said laser energy outside of said control volume.
For example, said EM system is further configured for directing said laser energy forward of said control volume.
For example, said EM system is further configured for preventing formation of an ice bridge outside of and proximate to said control volume.
Additionally or alternatively, for example, the device is made from non-metallic materials.
Additionally or alternatively, for example, the device is made from materials transparent and/or translucent with respect to the aforesaid EM energy provided by the at least one EM system.
Additionally or alternatively, for example, the body is transparent and/or translucent with respect to the aforesaid EM energy provided by the at least one EM system.
Additionally or alternatively, for example, the accretion surface is provided on a front wall of said body, and wherein at least said front wall is made from materials transparent and/or translucent with respect to the aforesaid EM energy provided by the at least one EM system.
Additionally or alternatively, for example, the accretion surface is provided on a front wall of said body, and wherein at least said front wall is transparent and/or translucent with respect to the aforesaid EM energy provided by the at least one EM system. 024906188-05 A feature of at least one example of the presently disclosed subject matter is that the device provides for positively detecting the presence of ice in the control volume, and for positively detecting the absence of ice (via the presence of only air) in the control volume.
Another feature of at least one example of the presently disclosed subject matter is that by providing the device with an electromagnetic energy system, in particular a laser-based ice melting system, for melting ice in the control volume, it is possible to do so by directly heating the ice and without the necessity to heat any part of the device itself, which can lead to a requirement for a smaller ice melting system, with lower power requirements, than would otherwise be the case.
Another feature of at least one example of the presently disclosed subject matter is that by providing the device with an electromagnetic energy system, in particular a laser-based ice melting system, for melting ice in the control volume, without the necessity to heat any part of the device itself, the whole device or much of the device, in particular the housing or body, can be made from non-metallic materials or from metallic materials, and/or from lightweight materials.
Another feature of at least one example of the presently disclosed subject matter is that by providing the device with an electromagnetic energy system, in particular a laser-based ice melting system, for melting ice in the control volume, the device can be reused multiple times during a flight mission.
BRIEF DESCRIPTION OF THE DRAWINGS In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:Fig. 1 is an isometric view of a device for detecting presence of ice in an airstream according to a first example of the presently disclosed subject matter.Figs. 2(a), 2(b), 2(c) show the device of Fig. 1 in side view, top view, and back view, respectively. 024906188-05 Fig. 3 shows, in isometric exploded view, the example of Fig. 1.Fig. 4 shows, in detail side view, the example of Fig. 1.Fig. 5 shows, in partial cross-sectional view, the example of Fig. 4 taken along Section A-A in Fig. 4.Fig. 6 shows, in partial cross-sectional view, the example of Fig. 4 taken along Section B-B in Fig. 4; Fig. 6(a) shows, in partial cross-sectional view, detail "C" of the example of Fig. 6.Fig. 7 schematically illustrates in top view alternate optical paths through an optical output surface of the example of Fig. 1.Fig. 8 schematically illustrates in top view alternate optical paths through a control volume of the example of Fig. 1.Fig. 9 shows, in partial cross-sectional view, an alternative variation of the example of Fig. 4.Fig. 10(a) and Fig. 10(b) show, in partial cross-sectional view and top view respectively, another alternative variation of the example of Fig. 4.Figs. 11(a), 11(b), 11(c) show in side view, bottom view, and front view, respectively a device for detecting presence of ice in an airstream according to a second example of the presently disclosed subject matter.Fig. 12 shows, in partial detail cross-sectional side view, a forward portion of the example of Figs. 11(a), 11(b), 11(c).Fig. 13 shows, in detail front view, a forward portion of the example of Figs. 11(a0, 11(b), 11(c).Fig. 14 schematically illustrates in front view alternate optical paths through an optical output surface of the example of Figs. 11(a), 11(b), 11(c).
DETAILED DESCRIPTION Referring to Figs. 1, 2(a), 2(b), 2(c), a device for detecting presence of ice in an airstream AS according to a first example of the presently disclosed subject matter, generally designated 100, comprises a body 200 defining an ice accretion control volume 210. 024906188-05 In at least this example, the device 100 comprises, or at least is configured for being operatively connected to, at least to one first electromagnetic (EM) transmitter 3configured for transmitting EM radiation, at least one first EM detector 400 configured for detecting said EM radiation, and at least one second EM detector 500 configured for detecting said EM radiation. The first EM detector 400 is different from the second EM detector 500.
Furthermore, in at least this example, the device 100 comprises, or at least is configured for being operatively connected to, at least to an electromagnetic (EM) system 600.
The body 200 defines a reference axis RA, associated with the control volume 210. The reference axis RA is generally transverse to the airstream direction AS.
Referring in particular to Fig. 3, the body 200 in this example is made from two parts, a forward housing part 215 and an aft housing part 222. In alternative variations of this example the body 200 can be formed as an integral component, or alternatively can be formed as an assembly of more than two parts.
The device 100 includes an interface portion 280 at one end of body 200, and the device 100 can be mounted to a structure via the interface portion 280. Such a structure can include, for example, an aircraft wing, fuselage or any other part of the aircraft on which ice accretion is to be monitored. Typically, the interface portion 280 is configured for enabling at least the control volume 210, or the entire body 200 to be exposed to the airstream AS.
The body 200 in at least this example is generally elongate having a longitudinal axis AA, and of generally circular transverse cross-sectional shape, and has an interface end 270 connected to the interface portion 280, and a free end 290 longitudinally opposed from the interface end 270 along the longitudinal axis AA. In at least this example the free end 290 is generally rounded, for example in the form of a hemisphere or part thereof.
For convenience, and referring to Fig. 1 for example, a device-based orthogonal coordinate system can be defined for the device 100 along mutually orthogonal axes: x- axis, y-axis, z-axis. The z-axis is parallel to the longitudinal axis AA. The y-axis is in the forward-aft direction. The x-axis is in the transverse direction.024906188-05 In alternative variations of this example, the body 200 can have any other suitable cross-section - for example, elliptical, polygonal etc. In yet other alternative variations of this example, the body 200 can have an aerodynamic profile, for example an aerofoil cross-section, for minimizing drag in the airstream AS.
Referring in particular to Figs. 1 and 4, the control volume 210 is defined by a cutout portion 220 in the body 200. The cutout portion 220 comprises an accretion surface 225 generally facing the airstream AS, and connected at one axial end thereof to a first end wall 230 and at another axial end thereof to a second end wall 240. The control volume 210 in this example is thus defined by the volume enclosed between the accretion surface 225, the first end wall 230, and the second end wall 240.
In this example the reference axis RA intersects the first end wall 230 and the second end wall 240.
Referring in particular to Figs. 3 and 5, the first end wall 230 comprises in this example a corresponding first side wall forward portion 230A, provided by forward housing part 215, and a corresponding first side wall aft portion 230B provided by the aft housing part 222.
In this example, the accretion surface 225 is generally rectangular and extends longitudinally generally parallel to the longitudinal axis AA.
Referring in particular to Figs. 1, 3, 5, 6, in this example the device 100 comprises a single first EM transmitter 300, comprising a first optical fiber element 320 having a body end 322 accommodated in suitable channel 320C provided in the body 200, and a coupling end 324 configured to be connected to a suitable EM radiation generator. An example of such a EM radiation generator is the CM97-xxx-7x device, provided by II-VI Photonics (USA).
The first optical fiber element 320 can include a single optical fiber or a bundle of optical fibers.
As best seen in Figs. 6(a) and 7, the body end 322 includes an optical refracting component 333 in the form of an optical output surface 323 at the free end thereof, facing or slightly projecting out of a suitable aperture 320S provided in first end wall 230. The 024906188-05 optical output surface 323 is at a slanted angle, herein referred to as prism apex angle a, to a plane PL orthogonal to the longitudinal axis AB of the first optical fiber element 320, and thus the optical output surface 323 is at a respective complementary angle g (i.e., 90° - a) to the longitudinal axis AB of the first optical fiber element 320 at the intersection between the longitudinal axis AB and the optical output surface 323.
Furthermore, the body end 322 includes a first portion 320A of the first optical fiber element 320 that has its corresponding optical axis AB substantially rectilinear and parallel to the longitudinal axis AA of the body 200. The body end 322 also includes a second portion 320B of the first optical fiber element 320 that has its corresponding optical axis AB substantially in the form of an arc of an imaginary circle of center C and radius R, wherein this arc corresponds to a sector of this imaginary circle having sector angle p.
In this example, sector angle p is about 11°, and radius R is about 50mm.
It is to be noted that in alternative variations of this example, the respective device can include a plurality of first EM transmitters.
In this example the device 100 comprises two separate second EM detectors 500, for clarity being designated reference numerals 500A and 500B, respectively. Each EM detector 500A, 500B comprises a respective second optical fiber element 520 (for clarity being designated reference numerals 520A and 520B) having a body end 5accommodated in a suitable channel 520C provided in the body 200, and a coupling end 524 configured to be connected to a suitable EM radiation detector module, for example the PDA36A or PDA20C5-EC provided by Thorlabs (USA). Each respective second optical fiber element 520 can instead include a single optical fiber or a bundle of optical fibers.
As best seen in Figs. 5 and 6, the body end 522 of each second EM detector 500A and 500B, includes a respective optical input surface 523, for clarity being designated reference numerals an optical input surface 523A, 523B, respectively, at the respective free end thereof, facing or slightly projecting out of a suitable aperture 520S provided in first end wall 230. Each respective optical input surface 523A, 523B is orthogonal to the longitudinal axis AF of the respective second optical fiber element 520 at the intersection between the longitudinal axis AF and the respective optical input surface 523A, 523B. 024906188-05 In this example, and as best seen in Fig. 5, the two respective optical input surfaces 523A, 523B are spaced from one another in a direction orthogonal from the accretion surface 225, and thus are at different spacings from the accretion surface 225.
It is to be noted that in alternative variations of this example, the respective device can instead include a single second EM detector, or more than two second EM detectors.
In this example the device 100 comprises a single first EM detector 400, comprising a third optical fiber element 420 having a body end 422 accommodated in a suitable channel 420C provided in the body 200, and a coupling end 424 configured to be connected to a suitable EM radiation detector module, for example the PDA36A or PDA20C5-EC provided by Thorlabs (USA). The third optical fiber element 420 can include a single optical fiber or a bundle of optical fibers.
As best seen in seen in Figs. 5 and 6, the body end 422 includes an optical input surface 423 at the free end thereof, facing or slightly projecting out of a suitable aperture 420S provided in first end wall 230. The optical input surface 423 is orthogonal to the longitudinal axis AD of the third optical fiber element 420 at the intersection between the longitudinal axis AD and the optical output surface 423.
In this example, the two respective optical input surfaces 523 are transversely spaced from optical input surface 423 in opposite transverse directions with respect to the optical output surface 323, and thus are on different sides with respect to the longitudinal axis AA.
It is to be noted that in alternative variations of this example, the respective device can instead include a plurality of second EM detectors.
In this example the device 100 further comprises a backscatter EM detector 700, comprising a fourth optical fiber element 720 having a body end 722 accommodated in a suitable channel 720C provided in the body 200, and a coupling end 724 configured to be connected to a suitable EM radiation detector module, for example the PDA36A or PDA20C5-EC provided by Thorlabs (USA). The fourth optical fiber element 720 can include a single optical fiber or a bundle of optical fibers. 024906188-05 As best seen in Figs. 5 and 6, the body end 722 includes an optical input surface 723 at the free end thereof, facing or slightly projecting out of a suitable aperture 720S provided in first end wall 230. The optical input surface 723 is orthogonal to the longitudinal axis AE of the fourth optical fiber element 720 at the intersection between the longitudinal axis AE and the optical output surface 723.
In at least this example, the optical input surface 723 is in close proximity to optical output surface 323.
It is to be noted that in alternative variations of this example, the respective device can instead include a plurality of backscatter EM detectors.
As best seen in Fig. 8, the first EM transmitter 300 is configured for transmitting said EM radiation from said first end wall 230 towards said second end wall 240. The first EM detector 400 is configured for detecting this EM radiation at a respective first location on said first end wall 230, i.e., at the aperture 420S. The two second EM detectors 500A, 500B are configured for detecting said EM radiation at respective second locations on the first end wall 230, i.e., at the aperture 520S Furthermore, the second end wall 240 comprises a first reflection surface 242 and a second reflection surface 244.
The first reflection surface 242 and the second reflection surface 244 are configured for reflecting therefrom any EM radiation incident thereon.
In particular, the first reflection surface 242 is configured for reflecting the EM radiation incident thereon from said first EM transmitter 320 towards the first EM detector 400 in the presence of only air in said control volume 210, i.e., in the absence of ice accreted in the control volume 210, and in particular, in the absence of ice accreted on and around optical output surface 323. As can be seen in Fig. 8, in conditions where there is air and no ice in the control volume 210, in a first optical path three representative main rays 380 (central ray 380B, and leftmost ray 380A, rightmost ray 380C) are transmitted from the first EM transmitter 300 via optical output surface 323, and reflected at corresponding points on the first reflection surface 242 towards the optical input surface 423 of the first EM detector 400. 024906188-05 The second reflection surface 244 is configured for reflecting the EM radiation incident thereon from the first EM transmitter 320 towards the second EM detectors 500 in the presence of ice in said control volume 210, in particular when the entire control volume 210 is filled with ice. As can be seen in Fig. 8, in conditions where there is ice present in the control volume, in a second optical path, three representative main rays 390 (central ray 390B, and leftmost ray 390A, rightmost ray 390C) are transmitted from the first EM transmitter 300 via optical output surface 323, and reflected at corresponding points on the second reflection surface 244 towards the optical input surfaces 523A, 523B of the two second EM detectors 500A, 500B, respectively.
For example, each one of first reflection surface 242 and the second reflection surface 244 is in the form of a concave mirror.
It is to be noted that if there is ice accretion up to the level of the lower optical input surface 523B, but has not yet reached the level of the upper optical input surface 523A, this provides an indication of partial ice buildup. Furthermore, the time lapse between ice reaching the level of the lower optical input surface 523B, and ice reaching the level of the upper optical input surface 523A, provides an ice accretion rate that can also be a useful parameter in at least some examples.
Referring in particular to Fig. 7, and as disclosed above, the optical output surface 323 is at a slanted angle, i.e., at the aforesaid prism apex angle a, to a plane PL orthogonal to the longitudinal axis AB of the first optical fiber element 320, and thus the optical output surface 323 is at a respective complementary angle g (i.e., 90° - a) to the longitudinal axis AB of the first optical fiber element 320 at the intersection between the longitudinal axis AB and the optical output surface 323. Thus, light rays LR parallel to the longitudinal axis AB of the first optical fiber element 320 are incident on the optical output surface 323 at an incident angle (to the respective normal N) corresponding to the prism apex angle a, and, according to Snell’s Law, are refracted at a refracted angle 0 to the longitudinal axis AB that depends on the refractive index n of the medium M outside of optical output surface 323, and within the control volume 210.
It is to be noted that light rays within the optical fiber element 320 are considered to be parallel to the longitudinal axis AB. 024906188-05 In this example, the prism apex angle a is set at 30°, and when the aforesaid medium M is air the corresponding refractive index (of air) is 1.00029, the corresponding refracted angle 0, for clarity marked in the figure as refracted angle 0 air , is about 48.6°.
On the other hand, when there is ice accreted within the control volume 210, this ice accretion extending from the first end wall 230 to the second end wall 240, then the aforesaid medium M is ice. The corresponding refractive index of clear ice is 1.31, and thus the corresponding refracted angle 0, for clarity marked in the figure as refracted angle 0 ice , is about 35.2°. The corresponding refractive index of rime ice is 1.31.
Thus there is an angular deviation of the refracted beam of A0 between (a) when there is only air in the control volume 210, and (b) when the control volume 210 is filled with clear ice. This angular deviation A0 = 0 air- 0 ice , and thus in this example, the angular deviation A0 is about (48.6° - 35.2° = ) 13.4°.
In at least this example, the longitudinal axis AA of the body 200 is chosen to lie about halfway within this angular deviation A0, so that the refracted ray RB is directed to the first reflective surface 242 when there is only air in the control volume 210, and so that the refracted ray RB is instead directed to the second reflective surface 244 only when the control volume 210 is filled with clear ice. Thus, in this example, the first reflective surface 242 and the second reflective surface 244 (and thus the first optical path and the second optical path) are on opposite lateral sides of the longitudinal axis AA (i.e., of the reference axis RA) of the body 200, since the center 325 (Fig. 7) of the optical output surface 323 is aligned with the longitudinal axis AA (in plan view of Fig. 7 or Fig. 8).
Arranging for the longitudinal axis AA of the body 200 to lie about halfway within this angular deviation A0 is accomplished by providing the aforesaid curvature to the second portion 320B of the first optical fiber element 320, thereby effectively angularly displacing the optical axis AB from the longitudinal axis AA of the body 200 by sector angle p. In this example, this angular displacement, and thus sector angle p, is set at about 11°.
It is to be noted that in alternative variations of this example, the prism apex angle a can be set at an angle different from 30°, and/or, the sector angle p can be set at an angle different from 11°.024906188-05 In alternative variations of this example, in which the center of the optical output surface 323 not is aligned with the longitudinal axis AA in plan view, the first reflective surface 242 and the second reflective surface 244 are instead on opposite lateral sides of an imaginary line that is parallel to the longitudinal axis AA but is aligned with the center of the optical output surface 323 in plan view.
The EM radiation is in at least one of the visible spectrum, ultraviolet (UV) spectrum, infrared (IR) spectrum.
In this example, the EM radiation is laser radiation of wavelength 650nm, which is in the visible spectrum. However, in alternative variations of this example the EM radiation can, additionally or alternatively, have any other suitable wavelength, for example 980nm.
The an electromagnetic (EM) system 600 is configured for providing EM energy to the control volume 210, this EM energy being configured for melting ice that in operation of the device 100 can accrete in the control volume 210, in particular in the accretion wall 225 as well as end walls 230 and 240.
In particular, in this example the EM system 600 is configured for providing said EM energy to the control volume 210, and in particular by directing said laser energy along a transmittal direction TD (Fig. 4) generally parallel to the reference axis RA.
Accordingly, the intensity I and/or wavelength X of the EM energy generated by the EM system 600 and transmitted to the control volume 210 are such as to enable the ice within the control volume 210 to become heated directly in response to receiving the EM energy, and to thereby melt, sufficient for such ice to be removed away from the control volume 210.
For example such intensity I of the EM energy can be 0.03 W/mm2, or at least between 0.01 W/mm2 and 0.1 W/mm2.
For example such wavelength X of the EM energy can be in the range of between about 1470nm and about 1550nm, for example any one of 1470nm, 1500nm or 1550nm.
In this example, and referring to Figs. 5 and 6 in particular, the EM system 6includes three optical fiber elements 620, for ease of reference being further identified with024906188-05 reference numerals 622, 624 626. It is to be noted that in alternative variations of this example the EM system 600 can include only one or only two optical fiber elements 620, or more than three optical fiber elements.
Each of the optical fiber elements 622, 624, 626 has a respective forward facing transmission end 622A, 624A, 626A, and in operation of the EM system 600 transmits EM energy along respective optical axes AG1, AG2, AG3 in a generally forward direction towards the second end wall 240.
Each of the optical fiber elements 622, 624, 626 has a respective a body end accommodated in suitable respective channel 622C, 624C, 626C provided in the body 200, and a respective coupling end configured to be connected to a suitable EM energy generating module, for example the 4PN-104 provided by Seminex (USA). The optical fiber elements 622, 624, 626 can each include a single optical fiber or a bundle of optical fibers.
In particular, the optical axes AG1, AG2, AG3 are directed towards the second end wall 240, traversing the longitudinal length of the control volume 210; thus, in operation of the EM system 600, EM energy transmitted via the optical fibers 622, 624, 626 irradiates any ice accreted in the control volume 210, enabling the ice therein to be melted.
For example, the EM radiation collectively provided via the optical fibers 622, 624, 626 illuminates most or all of the second end wall 240.
In this example, and as best seen in Fig. 5, the locations of the optical input surface 323, the optical output surfaces 423, 523, as well as the transmission ends 622A, 624A, 626A with respect to the surface 225 (Y-displacement) and the longitudinal axis AA (X- displacement) are as shown in Table I below. 024906188-05 Table ILocations of the Optical Input Surface, the Optical Output Surfaces, and the Transmission Ends on the First End Wall ~ with respect to the Accretion Surface (Y- displacement) and the Longitudinal Axis (X-displacement) Optical Input Surface; or Optical Output Surface; or Transmission EndX-displacement(mm)Y-displacement(mm) Optical output surface 323 -0.4 0.3 Optical input surface 423 2.4 0.3 Upper optical input surface 523A -2.4 0.4 Lower optical input surface 523B -2.4 0.1 Optical input surface 723 -0.4 0.6 Transmission end 622A 2.1 0.3 Transmission end 624A -0.1 0.3 Transmission end 626A -1.9 0.3 Thus, from the location of the optical input surface 323, and of the optical output surfaces 423, 523A, with respect to the surface 225 (Y-displacement) of 0.3mm, it is possible for the device 100 to be used for detection of ice accretion of thickness of at least 0.25mm.
For example, and referring in particular to Figs. 2(a), 2(b) and 2(c), the body 2has a height dimension B1, length dimension B2 and width dimension B3 according to the following example: B1= 28 mm; B2= 6.7 mm; B3 = 6.7 mm.
In such an example, the length dimension BY (Fig. 4) of the control volume 210 is about 3.35mm, and the length dimension BZ (Fig. 4) of the control volume 210 is between about 12mm to about 13mm. 024906188-05 In alternative variations of this example, the body 200 can have a different height dimension B1, and/or length dimension B2 and/or width dimension B3, for example as follows: B1= 70 mm; B2= 7 mm; B3 = 7 mm.In alternative variations of the above examples, the device 100, in particular the body 200, can have a height dimension B1, length dimension B2 and width dimension B3, different from the above.
In at least this example body 200, and in particular the forward housing part 2and the aft housing part 222, are made from non-metallic materials. For example, the body 200 can be made entirely from any suitable plastics materials, or any other suitable materials that are transparent or translucent to the wavelength X of the EM energy generated by the EM system 600, for example any one of: polycarbonate, glass.
Alternatively, in some alternative variations of the above examples, the body 200, and in particular one or more of the forward housing part 215, the aft housing part 222, are made from metallic materials, for example aluminum, titanium, steel, brass.
In operation of the device 100, mounted to a structure and facing the airstream AS, air impinges onto the accretion surface 225 via the control volume 210. In this example, the device 100 can be mounted to the structure such that the accretion surface 225 is facing the airstream AS, head-on, i.e., such that the airstream AS is parallel to the y-axis, and air impinges orthogonally onto the accretion surface 225.
However, in alternative variations of this example, the device 100 can be mounted to the structure such that the accretion surface 225 is facing the airstream AS at an angle, i.e., such that the airstream AS is at a non-zero angle to the y-axis, in which the device is effectively angularly displaced about the z-axis and/or about the x-axis by corresponding acute first tilt angle and second tilt angle, respectively, and air impinges at a corresponding composite acute angle onto the accretion surface 225. For example, such a first tilt angle can be in the range of 0° to 45°, and for example can be any suitable value in the group of: 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40°, 41°, 42°, 43°, 44°, 45°. For example, such a second tilt angle can be in the range of 0° to 45°, and for example can be any suitable value in the group of: 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 024906188-05 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26° 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40°, 41°, 42°, 43°, 44°, 45° So long as there is only air within the control volume 210, EM radiation transmitted by the first EM transmitter 300 via the optical output surface 323 is refracted thereat towards the first reflection surface 242 and towards the first EM detector 400 via the optical input surface 423.
Furthermore, when there is a presence of ice, which can include for example one or more of supercooled water droplets, snow particles or ice particles (for example clear ice or rime ice), in the airstream AS, some ice can begin to accrete in the control volume 210, in particular on the accretion surface 225 thereof, for example in a manner analogous to or corresponding to ice accretion that can be taking place on other areas of the aircraft, for example leading edges of the wings or other control surfaces.
As more and more ice accretes over the accretion surface 225 until the control volume 210 is totally blocked with ice, EM radiation transmitted by the first EM transmitter 300 via the optical output surface 323 is no longer refracted thereat towards the first reflection surface 242, but rather towards the second reflection surface 244 and towards the second EM detectors 500 via the optical input surfaces 523, as the result of the change in the medium (and thus of the refractive index) from air to ice between the optical output surface 323 and the second end wall 240.
The first EM detector 400 and the second EM detectors 500 are operatively coupled to controller 900, and controller 900 is also operatively connected to, and controls operation of, at least the electromagnetic (EM) system 600. In operation, the controller 9receives data or signals from the first EM detector 400 or from the second EM detectors 500 responsive to receiving the EM radiation thereat, and the controller 900 can then determine the status of ice accretion within the control volume 210.
The backscatter EM detector 700 is also operatively coupled to controller 900. In operation the controller 900 receives data or signals from the backscatter EM detector 7in order to provide additional data regarding whether there is water droplets (spray or cloud) or rime ice in the control volume 210. In conditions where the control volume 2is filled with air, ice or water there is nominally no backscatter in operation of the first EM 024906188-05 transmitter 300. Thus, EM radiation transmitted from the first EM transmitter 300 towards said second end wall 240 is not reflected back towards the first end wall 230, and thus backscatter EM detector 700 does not detect any such EM radiation. On the other hand, the presence of water spray or water vapor in the control volume 210 reflects EM radiation transmitted from the first EM transmitter 300 towards said second end wall 240 back towards the first end wall 230, and thus towards the backscatter EM detector 700. Thus, detection of EM radiation by the backscatter EM detector 700 is an indication of the presence of water spray or water vapor in the control volume 210.
Table II provides detection levels of EM radiation emitted from the first EM emitter 300 and detected by one or more of: the first EM detector 400; the upper second EM detector 500A; the lower second EM detector 500B; backscatter EM detector 700.
TABLE II Non-Dimensionalized Detection Levels in EM Detectors under Various Conditions reFirst Example Condition Status of Control VolumeFirst EMDetector400 BackscatterEMDetector700 LowerSecondEMDetector500B UpperSecondEMDetector500A A Air Only 5 0 0 0 B Water droplets(spray/cloud)3 2 2 C Clear Ice (thickness<0.25mm0 4 0 D Clear Ice (thickness>0.25mm0 5 4 E Rime Ice (thickness<0.25mm2 4 0 F Rime Ice (thickness>0.25mm4 5 4 024906188-05 The detection levels in Table II are nominal detected intensity levels, non- dimensionalised with respect to a nominal transmitted EM radiation intensity level, and wherein a value of "5" represents a maximum detected intensity.
Thus, in conditions where there is no ice in the control volume and this is filled only with air (Condition A in Table II), EM radiation emitted from the first EM emitter 300 is refracted by the optical refracting component 333 to the first reflective surface 2and from there to the first EM detector 400.
On the other hand, in conditions where the control volume 210 is filled with clear ice, or at least to a thickness of more than 0.25mm from the accretion surface 2(Condition D in Table II), EM radiation emitted from the first EM emitter 300 is instead refracted by the optical refracting component 333 to the second reflective surface 244 and from there to the second EM detectors 500. In both cases the backscatter EM detector 7nominally does not receive any reflected EM radiation originally emitted by the first EM emitter 300.
However, in conditions where only part of the control volume 210 is filled with clear ice (Condition C in Table II), for example where the control volume 210 is filled with clear ice to a thickness of less than 0.25mm from the accretion surface 225, EM radiation emitted from the first EM emitter 300 is refracted by the optical refracting component 3to the second reflective surface 244 and from there to the lower second EM detector 500B, but not to the upper second EM detector 500A, and it is also possible for some of the EM radiation emitted from the first EM emitter 300 to be concurrently refracted by the optical refracting component 333 to the first reflective surface 242 and from there to the first EM detector 400. However, in such a case, the level of the EM radiation received by the first EM detector 400 will tend to be less than is the case where there is only air in the control volume 210. Similarly, in such a case, the level of the EM radiation received by the lower second EM detector 500B will also tend to be less than is the case where there is only clear ice in the control volume 210. In such a case the backscatter EM detector 700 nominally does not receive any reflected EM radiation originally emitted by the first EM emitter 300.
In conditions where the control volume 210 is filled with rime ice, or at least to a thickness of more than 0.25mm from the accretion surface 225 (Condition F in Table II), EM radiation emitted from the first EM emitter 300 is refracted by the optical refracting024906188-05 component 333 to the second reflective surface 244 and from there to the second EM detectors 500. However, the backscatter EM detector 700 also receives some reflected EM radiation originally emitted by the first EM emitter 300.
In conditions where only part of the control volume 210 is filled with rime ice, for example where the control volume 210 is filled with rime ice to a thickness of less than 0.25mm from the accretion surface 225 (Condition E in Table II),, EM radiation emitted from the first EM emitter 300 is refracted by the optical refracting component 333 to the second reflective surface 244 and from there to the lower second EM detector 500B, but not to the upper second EM detector 500A, and it is also possible for some of the EM radiation emitted from the first EM emitter 300 to be concurrently received by the backscatter EM detector 700. However, in such a case, the level of the EM radiation received by the backscatter EM detector 700 will tend to be greater than is the case where there is rime ice has only accreted to less than 0.25mm thickness.
In conditions where the control volume 210 has no ice, but there are water droplets present in the control volume 210 (Condition B in Table II), it is possible that all four of the first EM detector 400, the two the second EM detectors 500, and the backscatter EM detector 700 all receive some EM radiation originally emitted by the first EM emitter 300. However, in such a case, the level of the EM radiation received by the first EM detector 400 will tend to be less than is the case where there is only air in the control volume 210. Similarly, in such a case, the level of the EM radiation received by the second EM detectors 500 will also tend to be less than is the case where there is only clear ice in the control volume 210.
Thus, the controller 900 can also be configured to determine whether or not the level of ice accretion has reached or passed critical thresholds, for example according to whether only one or both second EM detectors 500 are detecting ice. Such critical thresholds can correspond to, for example, analogous ice accretions in ice-sensitive parts of the aircraft, for example leading edges of the wings or other control surfaces, which could lead to significant or catastrophic loss in performance of the aircraft.
Responsive to determining the status of ice accretion, in particular whether such thresholds have been reached, the controller 900 can selectively take one or more of the following courses of action:024906188-05 (a) Transmit a suitable ice accretion warning signal to the user.(b) Initiate operation of any anti-icing systems in the aircraft.(c) Activate operation of the EM system 600 to remove the ice accretion in the control volume 210.
Regarding option (c), this feature allows the device 100 to continue operating to determine whether there is fresh ice accretion, and to thus monitor ongoing ice accretion. Otherwise, it is possible for the ice already accreted in control volume 210 to remain there, even when there is no further ice present in the airstream, and thus provide false indications to the controller 900.
Nominal operation of the EM system 600 results in melting of ice accreted at the control volume 210, and the melted ice flows out of the control volume 210 and into the airstream aft of the device 100.
In a variation of the EM system 600, and referring to Fig. 9, the EM system 6further comprises at least one auxiliary optical fiber element 628 having a forward facing transmission end 628A, and in operation of the EM system 600 transmits EM energy along respective optical axis AG4 in a generally axial direction towards the second end wall 240. The auxiliary optical fiber element 628 has a body end accommodated in suitable channel 628C provided in an auxiliary body portion 201, and a respective coupling end configured to be connected to the EM energy generating module. The auxiliary body portion 201 is provided over the forward housing part 215 so that the forward facing transmission end 628A is above the height of the first end wall 230.
The auxiliary optical fiber element 628 can include a single optical fiber or a bundle of optical fibers.
The optical fibers 622, 624, 626 are configured to provide suitable respective divergence angles DAX, for the EM energy transmitted via the optical fibers 622, 624, 626, to optimize the delivery of said EM energy to the control volume 210 as well as to an additional volume forward of the control volume 210 where additional ice buildup may be expected and it is desired to remove in operation of the device.
In this example, each one of the divergence angles DAX is about 20°, while in alternative variations of this examples the divergence angles DAX can each be any suitable024906188-05 value in the range 10° to 40°, more particularly in the range 15° to 35°, more particularly in the range 20° to 30°. Thus for example, the divergence angles DAX can each be any suitable value in the group of: 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40.
In particular, the optical axis AG4 is directed towards the second end wall 240, traversing the longitudinal length of the control volume 210, but displaced therefrom. Thus, in operation of the EM system 600, EM energy transmitted via the optical fiber 6irradiates any ice accreted outside, in particular forward of, the control volume 210, enabling the ice therein to be melted. For example, should an excessive amount of ice be accreted over and above the control volume 210, it is possible that EM energy transmitted only via the optical fibers 622, 624, 626 melts ice accreted within the control volume 210, but does not affect additional ice accreted in a region outside (for example, forward of) the control volume 210. This could leave a "bridge" of ice partially or fully spanning the length between the first end wall 230 and the second end wall 240, while the control volume 210 itself remains free of ice. In such a situation, and in the absence of operation of auxiliary optical fiber element 628, the controller 900 could determine there is no ice accretion within the control volume 210, even in environmental conditions in which ice continues to accrete forward of the ice "bridge". Operation of the auxiliary optical fiber element 628 in such conditions provides melting of at least part of the ice "bridge".
A variation of the example of Fig. 9 is illustrated in Figs. 10(a) and 10(b), in which a modified device 100’ is similar to the device 100 as disclosed above, mutatis mutandis, with the main difference being that in the modified device 100’ a modified forward housing part 215’ replaces the aforementioned forward housing part 215. The modified forward housing part 215’ is similar to the aforementioned forward housing part 215, mutatis mutandis, but includes a corresponding modified first side wall forward portion 230A’ that is spaced by an axial spacing X1 from the first side wall aft portion 230B of the aft housing part 222 in a direction away from the second side wall 240.
In this example the EM system 600 further comprises a first auxiliary optical fiber element 646 having a forward facing first transmission end 646A, and a second auxiliary optical fiber element 648 having a forward facing second transmission end 648A. In operation of the EM system 600 the first and second auxiliary optical fiber elements 646, 024906188-05 648 transmit EM energy along respective optical axes AX1 and AX2 in a generally axial direction (i.e., generally parallel to the z-axis, but can be slightly inclined thereto along the X-Z plane and/or the Y-Z plane, for example by inclinations in the range 5° to 20°) towards the second end wall 240. The auxiliary optical fiber elements 646, 648 each has a body end accommodated in suitable channels 646C, 648C provided in the modified forward housing part 215’, and a respective coupling end configured to be connected to the EM energy generating module. The first transmission end 646A and the second transmission end 648B are provided on the forward housing part 215’ above the height of the forward facing transmission ends 622A, 624A, 626A, of the optical fiber elements 622, 624, 626, at a height HX1 from the accretion surface 225.
In this example the EM system 600 further comprises a third auxiliary optical fiber element 647 having a forward facing third transmission end 647A, and a fourth auxiliary optical fiber element 649 having a forward facing fourth transmission end 649A. In operation of the EM system 600 the third and fourth auxiliary optical fiber elements 647,649 transmit EM energy along respective optical axes AX3 and AX4 in partially forward directions, angled to the z-axis by corresponding angles D1, D2 respectively along an Y-Z plane. Furthermore, axes AX3 and AX4 can also be tilted inwardly towards the longitudinal axis AA by respective angles E1, E2 to the z-axis along an X-Z plane.
In this example, angles D1, D2 are the same, while in alternative variations of this examples the angles D1, D2 can be different from one another.
In this example, angles D1, D2 are each 30°, while in alternative variations of this examples the angles D1, D2 can each be any suitable value in the range 0° to 90°, more particularly in the range 10° to 80°, more particularly in the range 15° to 70°, more particularly in the range 20° to 60°, more particularly in the range 25° to 50°, more particularly in the range 30° to 45°. Thus for example, the angles D1, D2 can each be any suitable value in the group of: 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°,15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°,34°, 35°, 36°, 37°, 38°, 39°, 40°, 41°, 42°, 43°, 44°, 45°, 46°, 47°, 48°, 49°, 50°, 51°, 52°,53°, 54°, 55°, 56°, 57°, 58°, 59°, 60°, 61°, 62°, 63°, 64°, 65°, 66°, 67°, 68°, 69°, 70°, 71°,72°, 73°, 74°, 75°, 76°, 77°, 78°, 79°, 80°, 81°, 82°, 83°, 84°, 85°, 86°, 87°, 88°, 89°, 90°. 024906188-05 In this example, angles E1, E2 are each 15°, while in alternative variations of this examples the angles D1, D2 can each be any suitable value in the range 0° to 40°, more particularly in the range 10° to 30°. Thus for example, the angles E1, E2 can each be any suitable value in the group of: 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40°.
The auxiliary optical fiber elements 647, 649 each has a body end accommodated in suitable channels 647C, 649C provided in the modified forward housing part 215’ and also in an auxiliary body portion 201’ affixed to the modified forward housing part 215’, and a respective coupling end configured to be connected to the EM energy generating module. The third transmission end 647A and the fourth transmission end 649A are provided on the forward housing part 215’ forward of and at a height HX2 from the accretion surface 225, and by an axial spacing X2 from the first side wall aft portion 230B of the aft housing part 222 in a direction away from the second side wall portion 240.
The optical fibers 646, 647, 648, 649 are configured to provide suitable divergence angles DA1, DA2, DA3, DA4, respectively, for the EM energy transmitted via the optical fibers 646, 647, 648, 649 EM energy transmitted via the optical fibers 646, 647, 648, 649, respectively, to optimize the delivery of said EM energy to the control volume 210 as well as to an additional volume forward of the control volume 210 where additional ice buildup may be expected and it is desired to remove in operation of the device.
In this example, each one of the divergence angles DA1, DA2, DA3, DA4, are each about 20°, while in alternative variations of this examples the divergence angles DA1, DA2, DA3, DA4 can each be any suitable value in the range 10° to 40°, more particularly in the range 15° to 35°, more particularly in the range 20° to 30°. Thus for example, the divergence angles DA1, DA2, DA3, DA4 can each be any suitable value in the group of: 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40.
The first auxiliary optical fiber element 646, the second auxiliary optical fiber element 648, the third auxiliary optical fiber element 647, and the fourth auxiliary optical fiber element 649, can each include a single optical fiber or a bundle of optical fibers. 024906188-05 In particular, the optical axes AX1 and AX2 are directed towards the second end wall 240, traversing the longitudinal length of the control volume 210, while the axes AXand AX3 are directed towards the second end wall 240 and concurrently away from the accretion surface 225. Thus, in operation of the EM system 600, EM energy transmitted via the optical fibers 646, 647, 648, 649 irradiate any ice accreted inside of the control, volume 210, as well as outside, in particular forward of, the control volume 210, enabling the ice therein to be melted. For example, should an excessive amount of ice be accreted over and forward of the control volume 210, EM energy transmitted via the optical fibers 646, 647, 648, 649 is configured to melt any ice partially or fully spanning the length between the first end wall 230 and the second end wall 240, and within the divergence angles thereof, nominally avoiding the creation of an ice "bridge" over the control volume 210, which itself remains free of ice.
In this example, the device 100’ can be mounted to the structure such that the accretion surface 225 is facing the airstream AS, head-on, i.e., such that the airstream AS is parallel to the y-axis, and air impinges orthogonally onto the accretion surface 225. In such a case the first transmission end 646A, second transmission end 648A third transmission end 647A, and fourth transmission end 649A can be symmetrically arranged with respect to the y-z plane. For example first transmission end 646A and the third transmission end 647A on the one hand, and the second transmission end 648A and the fourth transmission end 649A on the other hand, symmetrically arranged on opposite sides of the y-z plane.
However, in alternative variations of this example, the device 100’ can be mounted to the structure such that the accretion surface 225 is facing the airstream AS at an angle, i.e., such that the airstream AS is at a non-zero angle to the y-axis, in which the device is effectively angularly displaced about the z-axis by the aforesaid first acute angle. In such a case the device 100’ can be further modified such that the first transmission end 646A, second transmission end 648A third transmission end 647A, and fourth transmission end 649A are symmetrically arranged with respect to a z-AS plane, i.e., a plane on which both the z-axis and the AS direction extend. For example first transmission end 646A and the third transmission end 647A on the one hand, and the second transmission end 648A and the fourth transmission end 649A on the other hand, symmetrically arranged on opposite sides of the z-AS plane. 024906188-05 In alternative variations of the above examples, the EM system 600 can be omitted or replaced with a different heating system for melting any ice accreted in the control volume 210.
Referring to Figs. 11(a), 11(b), 11(c), 12, 13, 14, a device for detecting presence of ice in an airstream AS according to a second example of the presently disclosed subject matter, generally designated 1100, is similar to the device 100 according to first example and alternative variations thereof, as disclosed herein, mutatis mutandis, with some differences as will become apparent herein.
Thus, the device 1100 comprises a body 1200 (also interchangeably referred to as a housing) defining an ice accretion control volume 1210, similar to body 200 and control volume 210, respectively, of the first example as disclosed herein, mutatis mutandis, with some differences.
In the second example, the body 1200 is made from two parts, a forward housing part 1200A and an aft housing portion 1200B. In alternative variations of this example the body 1200 can be formed as an integral component, or alternatively can be formed as an assembly of more than two parts.
The device 1100 includes an interface portion 1280 at one end of body 1200, and the device 1100 can be mounted to a structure via the interface portion 1280. Such a structure can include, for example, an aircraft wing, fuselage or any other part of the aircraft on which ice accretion is to be monitored. Typically, the interface portion 1280 is configured for enabling at least the control volume 1210, or the entire body 1200 to be exposed to the airstream AS.
The device 1100 further includes a front wall 1222 at the other end of body 1200, generally facing the airstream AS.
In this example the body 1200 is generally hollow, but in alternative variations of this example the body 1200 is not hollow and is filled with material, for example a non- gaseous material, for example a solid material.
In this example, and as best seen in Figs. 11(a), 11(b), 11(c) the body 1200, in particular an aft portion thereof, has a generally aerodynamic profile, for example an 024906188-05 elliptical cross-section, for minimizing drag in the airstream AS, and thus the entire body 1200 can be exposed to the airstream AS.
In alternative variations of this example, the body 1200 can be generally tubular and can have any suitable cross-section - for example aerofoil section, circular, square, rectangular, polygonal etc.
Furthermore, and referring particularly to Fig. 11(a), in this example the body 12is elbow-shaped, i.e., the body 1200 has a body central axis AA therethrough in which a front portion AAF of the body central axis AA is angularly displaced from an aft portion AAA of the body central axis AA by an elbow angle E. In this example the elbow angle E is about 90°, taken along a median plane MP.
However, in other alternative variations of this example the body 1200 can have any other suitable elbow angle, and/or any other suitable shape; for example in other alternative variations of this example the aft elbow angle E is acute or obtuse.
The control volume 1210 is provided at a forward portion of the body 1200 in particular with respect to a front body wall 1205, such that in operation of the device 11is facing the airstream AS.
For convenience, and referring to Figs. 11(a), 11(b), 11(c) for example, a device- based orthogonal coordinate system can be defined for the device 1100 along mutually orthogonal axes: x-axis, y-axis, z-axis. The y-axis is parallel to the front portion AAF of the body central axis AA. The z-axis is in the top-bottom direction, and the x-axis is in the transverse direction.
In at least this example, the body 1200 is symmetrical about median plane MP, which is parallel to the y-z plane.
In a similar manner to that of the first example, mutatis mutandis, and referring in particular to Figs. 12 and 13, the control volume 1210 is defined by a cutout portion 12in the front end of body 1200. The cutout portion 1220 comprises an accretion surface 1225 (on an external, exposed side of front wall 1222), generally facing the airstream AS, similar to accretion surface 225, mutatis mutandis. The accretion surface 1225 is connected at one axial end thereof to a first end wall 1230 and at another axial end thereof (along the 024906188-05 z-axis) to a second end wall 1240, similar to first end wall 230 and second end wall 240, mutatis mutandis. The control volume 1210 in this example is thus defined by the volume enclosed between the accretion surface 1225, the first end wall 1230, and the second end wall 1240.
In this example, the accretion surface 1225 is generally rectangular and extends longitudinally generally orthogonal to the front portion AAF of the body central axis AA.
In a similar manner to the first example, mutatis mutandis, the body 1200 also defines a reference axis RA, associated with the control volume 1210, the reference axis RA being generally transverse to the airstream direction AS.
In this example the reference axis RA also intersects the first end wall 1230 and the second end wall 1240.
As best seen in Fig. 13, a central axis AO can be defined, generally centrally disposed within control volume 1210, traversing between the first end wall 1230 and the second end wall 1240. The central axis AO is generally parallel to the z-axis, and can be defined on the median plane MP.
In at least this example, the device 1100 comprises, or at least is configured for being operatively connected to, at least one first electromagnetic (EM) transmitter 13configured for transmitting EM radiation, at least one first EM detector 1400 configured for detecting said EM radiation, and at least one second EM detector 1500 configured for detecting said EM radiation, the first EM detector 1400 being different from the second EM detector 1500. Furthermore, in at least this example, the device 1100 comprises, or at least is configured for being operatively connected to, at least to an electromagnetic (EM) system 1600. The at least one first EM transmitter 1300, at least one first EM detector 1400, at least one second EM detector 1500, and EM system 1600 are similar or identical to the at least one first EM transmitter 300, at least one first EM detector 400, at least one second EM detector 500, and EM system 600 of the first example as disclosed herein, mutatis mutandis.
In particular, in this example the EM system 1600 is configured for providing said EM energy to the control volume 1210, and in particular by directing said laser energy along a transmittal direction TD’ (Fig. 12) generally orthogonal to the reference axis RA.024906188-05 Referring in particular to Fig. 12 in the second example the device 1100 comprises a single first EM transmitter 1300, comprising a first optical fiber element 1320 having a body end 1322 accommodated in suitable channel (not shown) provided in the body 1200, and a coupling end 1324 configured to be connected to a suitable EM radiation generator. An example of such a EM radiation generator is the CM97-xxx-7x device, provided by II- VI Photonics (USA).
It is to be noted that in alternative variations of this example, the respective device can include a plurality of first EM transmitters.
The first optical fiber element 1320 can be similar to the first optical fiber element 320, as disclosed herein for the first example, mutatis mutandis, and can similarly include a single optical fiber or a bundle of optical fibers.
As best seen in Figs. 12, 13, and 14, the body end 1322 includes an optical refracting component 1333 and an optical folding component 1335. The optical refracting component 1333 and the optical folding component 1335 are in optical communication with one another, and in particular in this example the optical refracting component 13and the optical folding component 1335 are in abutting contact with one another.
The optical refracting component 1333 can be similar to the optical refracting component 333 as disclosed herein for the first example, mutatis mutandis, and is in the form of an optical output surface 1323 at the free end thereof, facing or slightly projecting out of a suitable aperture 1320S provided in first end wall 1230.
In the second example, the optical refracting component 1333 is in the form of a triangular optical prism, in particular a right-angled prism, in which the optical output surface 1323 is at a slanted angle, herein referred to as first prism apex angle a, to an optical input surface 1324 of the optical refracting component 1333.
In the second example, the optical folding component 1335 is in the form of a triangular optical prism, in particular a right-angled prism, having a prism optical input surface 1326 at a non-zero angle, herein referred to as second prism apex angle p, to prism optical output surface 1327 thereof, and further having an internal reflecting surface 1329. In this example, second prism apex angle p is 90°, and the right-angled prism has an isosceles prism cross section, with acute angles of 45°.024906188-05 In the second example, the prism optical output surface 1327 is optical communication with, in particular facing, more in particular in abutting contact with, the optical input surface 1324.
The prism optical input surface 1326 is at a respective complementary angle g (i.e., 90° - a) to an imaginary line L that is normal to the prism optical output surface 1327.
The body end 1322 includes an optical output surface 1321 in optical communication with, in particular facing, more in particular in abutting contact with, the prism optical input surface 1326.
As best seen in Fig. 12, the optical folding component 1335 is positioned spatially within the body 1200 such as to fold EM radiation, transmitted by the first EM transmitter 1300 via body end 1322 and optical output surface 1321 normal to prism optical input surface 1326, towards the prism optical output surface 1327 (via reflection at reflecting surface 1329), and such that the EM radiation passes through the prism optical output surface 1327 orthogonally with respect to the prism optical output surface 1327.
In this manner, the transmitted EM radiation enters the optical refracting component 1333 orthogonally to the optical input surface 1324, and in a general direction towards the second end wall 1240.
As best seen in Fig. 12 and in Fig. 14, the optical folding component 1335 is further tilted about the Y-axis such that the prism optical output surface 1327 is at an angle P to the X-Y plane when viewed on the X-Z plane. In this example, angle p is about 11°. Similarly, the optical input surface 1324 is also at angle p to the X-Y plane when viewed on a X-Z plane.
In this example the device 1100 comprises a single second EM detector 1500, comprising a respective second optical fiber element 1520 having a body end 15accommodated in a suitable channel (not shown) provided in the body 1200, and a coupling end 1524 configured to be connected to a suitable EM radiation detector module, for example the PDA36A or PDA20C5-EC provided by Thorlabs (USA). Each respective second optical fiber element 1520 can instead include a single optical fiber or a bundle of optical fibers. 024906188-05 As best seen in Fig. 12, the body end 1522 of the second EM detector 15includes an optical input surface 1523 at the free end thereof, optically coupled to a second optical folding component 1735.
In the second example, the second optical folding component 1735 is in the form of a triangular optical prism, in particular a right-angled prism, having a prism optical input surface 1726 at a non-zero angle, herein referred to as third prism apex angle q’, to prism optical output surface 1727 thereof, and further having an internal reflecting surface 1729. In this example, third prism apex angle q’ is 90°, and the right-angled prism has an isosceles prism cross section, with acute angles of 45°.
The prism optical input surface 1726 is facing a suitable aperture 1520S provided in second end wall 1240.
The optical input surface 1523 is optically coupled to the prism optical output surface 1727 of second optical folding component 1735.
Thus, EM radiation entering the second optical folding component 1735 via the prism optical input surface 1726 is reflected (or folded) by the reflecting surface 17towards the prism optical output surface 1727 and thence to the optical input surface 1523, thereby channeling the EM radiation from prism optical input surface 1726 to the second EM detector 1500.
It is to be noted that in alternative variations of this example, the respective device can instead include more than one second EM detectors.
In this example the device 1100 comprises a single first EM detector 1400, comprising a third optical fiber element 1420 having a body end 1422 accommodated in a suitable channel (not shown) provided in the body 1200, and a coupling end 14configured to be connected to a suitable EM radiation detector module, for example the PDA36A or PDA20C5-EC provided by Thorlabs (USA). The third optical fiber element 1420 can include a single optical fiber or a bundle of optical fibers.
As best seen in Fig. 12, the body end 1422 of the first EM detector 1400 includes an optical input surface 1423 at the free end thereof, optically coupled to a third optical folding component 1835. 024906188-05 In the second example, the third optical folding component 1835 is in the form of a triangular optical prism, in particular a right-angled prism, having a prism optical input surface 1826 at a non-zero angle, herein referred to as third prism apex angle q", to prism optical output surface 1827 thereof, and further having an internal reflecting surface 1829. In this example, third prism apex angle q’ is 90°, and the right-angled prism has an isosceles prism cross section, with acute angles of 45°.
The prism optical input surface 1826 is facing a suitable aperture 1420S provided in second end wall 1240.
The optical input surface 1423 is optically coupled to the prism optical output surface 1827 of third optical folding component 1835.
Thus, EM radiation entering the third optical folding component 1835 via the prism optical input surface 1826 is reflected (or folded) by the reflecting surface 18towards the prism optical output surface 1827 and thence to the optical input surface 1423, thereby channeling the EM radiation from prism optical input surface 1826 to the first EM detector 1400.
It is to be noted that in alternative variations of this example, the respective device can instead include a plurality of second EM detectors.
In this example the device 1100 does not include a backscatter EM detector. However, in alternative variations of this example the device can include a backscatter EM detector, for example comprising a fourth optical fiber element having a body end accommodated in a suitable channel provided in the body 1200, and a coupling end configured to be connected to a suitable EM radiation detector module, for example the PDA36A or PDA20C5-EC provided by Thorlabs (USA); such a fourth optical fiber element can include a single optical fiber or a bundle of optical fibers.
It is to be noted that in alternative variations of this example, the respective device can instead include a plurality of backscatter EM detectors.
As best seen in Fig. 12 and Fig. 13, the first EM transmitter 1300 is configured for transmitting said EM radiation from said first end wall 1230 towards said second end wall 1240. The first EM detector 1400 is configured for detecting this EM radiation at a 024906188-05 respective first location on second end wall 1240, i.e., at the aperture 1420S. The second EM detector 1500 is configured for detecting said EM radiation at respective second locations on the second end wall 1240, i.e., at the aperture 1520S In alternative variations of this example, the second end wall 1240 comprises a first reflection surface and a second reflection surface, for example similar to the first example, mutatis mutandis, and the first EM detector 1400 and the second EM detector 1500 are configured for detecting said EM radiation at respective locations on the first end wall 1230. In such cases, the first reflection surface and the second reflection surface are configured for reflecting therefrom any EM radiation incident thereon.
In particular, the prism optical input surface 1826 is configured for receiving EM radiation from said first EM transmitter 1320 and channeling the EM radiation towards the first EM detector 1400 in the presence of only air in said control volume 1210, i.e., in the absence of ice accreted in the control volume 1210, and in particular, in the absence of ice accreted on and around optical output surface 1323. As can be seen in Fig. 13, in conditions where there is air and no ice in the control volume 1210, in a first optical path, a representative main ray 1380 is transmitted from the first EM transmitter 1300 via optical output surface 1323, towards the prism optical input surface 1826 of the first EM detector 1400.
The prism optical input surface 1726 is configured for receiving EM radiation incident from said first EM transmitter 1320 and channeling the EM radiation towards the second EM detector 1500 in the presence of ice in said control volume 1210, in particular when the entire control volume 1210 is filled with ice. As can be seen in Fig. 13, in conditions where there is ice present in the control volume, in a second optical path a representative main ray 1390 is transmitted from the first EM transmitter 1300 via optical output surface 1323, towards the prism optical input surface 1726 of the second EM detector 500.
Referring in particular to Fig. 14, and as disclosed above, the optical output surface 1323 is at a slanted angle, i.e., at the aforesaid prism apex angle a, to prism optical output surface 1327 and the optical input surface 1324. 024906188-05 Thus, light rays LR orthogonal to prism optical output surface 1327 and the optical input surface 1324 are incident on the optical output surface 1323 at an incident angle (to the respective normal N) corresponding to the prism apex angle a, and, according to Snell’s Law, are refracted at a refracted angle 0 to this normal N, wherein refracted angle depends on the refractive index n of the medium M outside of optical output surface 1323, and within the control volume 1210.
It is to be noted that light rays within the optical fiber element 1320 are considered to be parallel to the longitudinal axis of the optical fiber element 1320, and are folded via the first optical folding component 1335 in a direction towards, and orthogonal to, the prism optical output surface 1327 and the optical input surface 1324 In this example, the prism apex angle a is set at 30°, and when the aforesaid medium M is air the corresponding refractive index (of air) is 1.00029, the corresponding refracted angle 0, for clarity marked in the figure as refracted angle 0 air , is about 48.6°.
On the other hand, when there is ice accreted within the control volume 1210, this ice accretion extending from the first end wall 1230 to the second end wall 1240, then the aforesaid medium M is ice. The corresponding refractive index of clear ice is 1.31, and thus the corresponding refracted angle 0, for clarity marked in the figure as refracted angle 0 ice , is about 35.2°. The corresponding refractive index of rime ice is 1.31.
Thus, as with the first example, mutatis mutandis, there is an angular deviation of the refracted beam of A0 between (a) when there is only air in the control volume 1210, and (b) when the control volume 1210 is filled with clear ice. This angular deviation A0 = 0 air- 0 ice , and thus in this example, the angular deviation A0 is about (48.6° - 35.2° = ) 13.4°.
In at least this example, the central axis OA of the control volume 1210 is chosen to lie about halfway within this angular deviation A0, so that the refracted ray RB is directed to the prism optical input surface 1826 when there is only air in the control volume 1210, and so that the refracted ray RB is instead directed to the prism optical input surface 1726 only when the control volume 1210 is filled with clear ice. Thus, in this example, the prism optical input surface 1826 and the prism optical input surface 17(and thus the first optical path and the second optical path) are on opposite lateral sides of024906188-05 the central axis OA (and thus of the reference axis RA) of the control volume 1210, since the center 1325 (Fig. 14) of the optical output surface 1323 is aligned with the central axis OA (in plan view of Fig. 14).
Arranging for the central axis OA of control volume 1210 to lie about halfway within this angular deviation A0 is accomplished by providing the aforementioned tilt of the optical folding component 1335 about the Y-axis such that the prism optical output surface 1327 is at an angle p to the X-Y plane when viewed on the X-Z plane.
In this example, this angular displacement of this tilt, and thus angle p, is set at about 11°.
It is to be noted that in alternative variations of this example, the prism apex angle a can be set at an angle different from 30°, and/or, the angle p can be set at an angle different from 11°.
The EM radiation for this example is in at least one of the visible spectrum, ultraviolet (UV) spectrum, infrared (IR) spectrum.
In this example, the EM radiation is laser radiation of wavelength 650nm, which is in the visible spectrum. However, in alternative variations of this example the EM radiation can, additionally or alternatively, have any other suitable wavelength, for example 980nm.
The electromagnetic (EM) system 1600 is configured for providing EM energy to the control volume 1210, this EM energy being configured for melting ice that in operation of the device 1100 can accrete in the control volume 1210, in particular in the accretion wall 1225 as well as end walls 1230 and 1240. Thus, the electromagnetic (EM) system 1600 can be similar to EM system 600 as disclosed herein for the first example, mutatis mutandis.
It is to be noted that the front wall 1222 is transparent and/or translucent with respect to the aforesaid EM energy provided by the EM system 1600.
Accordingly, the intensity I and/or wavelength X of the EM energy generated by the EM system 1600 and transmitted to the control volume 1210 via the front wall 12are such as to enable the ice within the control volume 1210 to become heated directly in024906188-05 response to receiving the EM energy, and to thereby melt, sufficient for such ice to be removed away from the control volume 1210.
For example such intensity I of the EM energy can be 0.03 W/mm2, or at least between 0.01 W/mm2 and 0.1 W/mm2.
For example such wavelength X of the EM energy can be in the range of between about 1470nm and about 1550nm, for example any one of 1470nm, 1500nm or 1550nm.
In this example, and referring to Fig. 12 in particular, the EM system 1600 includes an optical fiber element 1620. It is to be noted that in alternative variations of this example the EM system 1600 can include more than one optical fiber elements.
The optical fiber element 1620 has a forward facing transmission end 1620A, and in operation of the EM system 1600 transmits EM energy along optical axis AGX in a generally forward direction towards the control volume 1210 via the front wall 1222 and accretion surface 1225.
Thus, in this example the EM system 1600 is configured for providing said EM energy to the control volume 1210, and in particular by directing said laser energy along a transmittal direction along optical axis AGX (Fig. 12) towards the control volume 12having first traversed the accretion surface 1225. Thus, in the second example, the transmittal direction and thus optical axis AGX intersects the accretion surface. Furthermore in the second example, the forward facing transmission end 1620A and the control volume 1210 are on opposite sides of the accretion surface 1225 with respect to optical axis AGX.
The optical fiber element 1620 has a body end 1622 (having transmission end 1620A) accommodated in suitable channel (not shown) provided in the body 1200, and a coupling end 1624 configured to be connected to a suitable EM energy generating module, for example the 4PN-104 provided by Seminex (USA), or, the M1470 product by Photontec (Germany). The optical fiber element 1620 can each include a single optical fiber or a bundle of optical fibers.
In particular, the optical axis AGX is directed towards the control volume 1210 via the front wall 1222 and the accretion surface 1225, traversing the height H of the control 024906188-05 volume 1210, and beyond; thus, in operation of the EM system 1600, EM energytransmitted via the optical fiber 1620 irradiates any ice accreted in the control volume1210, enabling the ice therein to be melted.
For example, the EM radiation collectively provided via the optical fibers 16illuminates most or all of the control volume 1210.
For example, and referring in particular to Figs. 11(a), 11(b) and 11(c), the body 1200 has a height dimension BB1, length dimension BB2 and width dimension BBaccording to the following examples:Example 1: BB1 = 60 mm; BB2 = 80 mm; BB3 = 17 mm.Example 2: BB1 = 60 mm; BB2 = 100 mm; BB3 = 17 mm.Example 3: BB1 = 40 mm; BB2 = 54 mm; BB3 = 17 mm.Example 4: BB1 = 35 mm; BB2 = 50 mm; BB3 = 15 mm.
In such examples, the height dimension H (Fig. 12) of the control volume 1210 is about 3.35mm, and the length dimension T (Fig. 12) of the control volume 1210 is between about 12mm to about 13mm.
In alternative variations of the above examples, the device 1100, in particular the body 1200, can have a height dimension BB1, length dimension BB2 and width dimension BB3, different from the above.
In at least this example body 1200, and in particular the forward body part 1210A and the aft housing part 1210B, are made from non-metallic materials. For example, the housing 1200 can be made entirely from any suitable plastics materials, or any other suitable materials that are transparent or translucent to the wavelength X of the EM energy generated by the EM system 1600, for example any one of: polycarbonate, glass.
Alternatively, in some alternative variations of the above examples, the body 1200, and in particular one or more of the forward housing part 1210A, the aft housing part 1210B, are made from metallic materials, for example aluminum, titanium, steel, brass, with the exception of forward wall 1222, which is instead made from suitable plastics materials, or any other suitable materials that are transparent or translucent to the wavelength X of the EM energy generated by the EM system 1600, for example any one of: polycarbonate, glass.024906188-05 In operation of the device 1100, mounted to a structure and facing the airstream AS, air impinges onto the accretion surface 1225 via the control volume 1210. In this example, the device 1100 can be mounted to the structure such that the accretion surface 1225 is facing the airstream AS, head-on, i.e., such that the airstream AS is parallel to the y-axis, and air impinges orthogonally onto the accretion surface 1225.
However, in alternative variations of this example, the device 1100 can be mounted to the structure such that the accretion surface 1225 is facing the airstream AS at an angle, i.e., such that the airstream AS is at a non-zero angle to the y-axis, in which the device is effectively angularly displaced about the z-axis and/or about the x-axis by corresponding acute first tilt angle and second tilt angle, respectively, and air impinges at a corresponding composite acute angle onto the accretion surface 225. Alternatively, the accretion surface 1225 can be tilted to the median plane MP of the body 1200 mounted to the structure such that the accretion surface 1225 is facing the airstream AS at an angle, i.e., such that the airstream AS is aligned with the y-axis, and in which the accretion surface 1225 is effectively angularly displaced about the z-axis and/or about the x-axis by corresponding acute first tilt angle and second tilt angle, respectively, and air impinges at a corresponding composite acute angle onto the accretion surface 1225.
For example, such a first tilt angle in each case can be in the range of 0° to 45°, and for example can be any suitable value in the group of: 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°,10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40°, 41°, 42°, 43°, 44°, 45°. Forexample, such a second tilt angle in each case can be in the range of 0° to 45°, and for example can be any suitable value in the group of: 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°,11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40°, 41°, 42°, 43°, 44°, 45° So long as there is only air within the control volume 1210, EM radiation transmitted by the first EM transmitter 1300 via the optical output surface 1323 is refracted thereat towards the first EM detector 1400 via the prism optical input surface 1826.
Furthermore, when there is a presence of ice, which can include for example one or more of supercooled water droplets, snow particles or ice particles (for example clear ice or rime ice), in the airstream AS, some ice can begin to accrete in the control volume 1210,024906188-05 in particular on the accretion surface 1225 thereof, for example in a manner analogous to or corresponding to ice accretion that can be taking place on other areas of the aircraft, for example leading edges of the wings or other control surfaces.
As more and more ice accretes over the accretion surface 1225 until the control volume 1210 is totally blocked with ice, EM radiation transmitted by the first EM transmitter 1300 via the optical output surface 1323 is no longer refracted thereat towards the prism optical input surface 1826, but rather towards the prism optical input surface 1726 and towards the second EM detector 1500 via the optical input surfaces 1523, as the result of the change in the medium (and thus of the refractive index) from air to ice between the optical output surface 1323 and the second end wall 1240.
The first EM detector 1400 and the second EM detector 1500 are operatively coupled to controller 1900, and controller 1900 is also operatively connected to, and controls operation of, at least the electromagnetic (EM) system 1600, for example in a similar manner to controller 900 of the first example, mutatis mutandis. In operation, the controller 1900 receives data or signals from the first EM detector 1400 and/or from the second EM detector 1500 responsive to receiving the EM radiation thereat, and the controller 1900 can then determine the status of ice accretion within the control volume 1210.
Table III provides detection levels of EM radiation emitted from the first EM emitter 1300 and detected by one or more of: the first EM detector 400 and the upper second EM detector 500.
TABLE III Non-Dimensionalized Detection Levels in EM Detectors under Various Conditions reSecond Example Condition Status of Control Volume First EMDetector 400Second EMDetector 500A Air Only 5 0B Water droplets (spray/cloud) 3 2C Clear Ice 0 5D Rime Ice 0 5 024906188-05 The detection levels in Table III are nominal detected intensity levels, non- dimensionalised with respect to a nominal transmitted EM radiation intensity level, and wherein a value of "5" represents a maximum detected intensity.
Thus, in conditions where there is no ice in the control volume 1210 and this is filled only with air (Condition A in Table III), EM radiation emitted from the first EM emitter 1300 is refracted by the optical refracting component to the prism optical input surface 1826 and from there to the first EM detector 1400.
On the other hand, in conditions where the control volume 1210 is filled with clear ice (Condition C in Table III, EM) radiation emitted from the first EM emitter 1300 is instead refracted by the optical refracting component to prism optical input surface 17and from there to the second EM detectors 1500.
In conditions where the control volume 1210 is filled with rime ice, (Condition D in Table III), EM radiation emitted from the first EM emitter 1300 is refracted by the optical refracting component prism optical input surface 1726 and from there to the second EM detector 1500.
In conditions where the control volume 210 has no ice, but there are water droplets present in the control volume 1210 (Condition B in Table III), it is possible that both the first EM detector 1400, and the second EM detector 1500, all receive some EM radiation originally emitted by the first EM emitter 1300. However, in such a case, the level of the EM radiation received by the first EM detector 1400 via prism optical input surface 18will tend to be less than is the case where there is only air in the control volume 1210. Similarly, in such a case, the level of the EM radiation received by the second EM detector 1500 prism optical input surface 1726 will also tend to be less than is the case where there is only clear ice in the control volume 1210.
Responsive to determining the status of ice accretion, in particular whether such thresholds have been reached, the controller 1900 can selectively take one or more of the following courses of action:(a) Transmit a suitable ice accretion warning signal to the user.(b) Initiate operation of any anti-icing systems in the aircraft. 024906188-05 (c) Activate operation of the EM system 1600 to remove the ice accretion in the control volume 1210.
Regarding option (c), this feature allows the device 1100 to continue operating to determine whether there is fresh ice accretion, and to thus monitor ongoing ice accretion. Otherwise, it is possible for the ice already accreted in control volume 1210 to remain there, even when there is no further ice present in the airstream, and thus provide false indications to the controller 1900.
Nominal operation of the EM system 1600 results in melting of ice accreted at the control volume 1210, and the melted ice flows out of the control volume 1210 and into the airstream aft of the device 1100. As best seen in Fig. 13, the sloped shapes of the first end wall 1230 and second end wall 1240 (Fig. 13) can facilitate removal of the melted ice from the control volume 1210.
The optical fiber 1620 is configured to provide a suitable divergence angles DAX’, for the EM energy transmitted via the optical fiber element 1620, to optimize the delivery of said EM energy to the control volume 1210 as well as to an additional volume forward of the control volume 1210 where additional ice buildup may be expected and it is desired to remove in operation of the device 1100. This set up for the EM system 1600 can, in at least some applications of this example, eliminate or reduce the risk of a "bridge" of ice partially or fully spanning the length between the first end wall 1230 and the second end wall 1240, even forward of the control volume 1210, since operation of the EM system 1600 generates a heating beam in the forward direction, providing melting of at least part of any such ice "bridge".
In this example, the divergence angle DAX’ is about 20°, while in alternative variations of this examples the divergence angle DAX’ can be any suitable value in the range 10° to 40°, more particularly in the range 15° to 35°, more particularly in the range 20° to 30°. Thus for example, the divergence angle DAX’ can be any suitable value in the group of: 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40.
In the above example, the device 1100 can be mounted to the structure, and/or is configured, such that the accretion surface 1225 is facing the airstream AS, head-on, i.e., 024906188-05 such that the airstream AS is parallel to the y-axis, and air impinges orthogonally onto the accretion surface 1225.
However, in alternative variations of this example, the device 1100 can be mounted to the structure, and/or can be configured, such that the accretion surface 1225 is facing the airstream AS at an angle, i.e., such that the airstream AS is at a non-zero angle to the y- axis, in which the device is effectively angularly displaced about the z-axis by the aforesaid first acute angle.
In alternative variations of the second example, the EM system 1600 can be omitted or replaced with a different heating system for melting any ice accreted in the control volume 1210.
Finally, it should be noted that the word "comprising" as used throughout the appended claims is to be interpreted to mean "including but not limited to".
While there has been shown and disclosed examples in accordance with the presently disclosed subject matter, it will be appreciated that many changes may be made therein without departing from the spirit of the presently disclosed subject matter. 024906188-05
Claims (37)
1. Device for detecting presence of ice in an airstream, comprising: - body defining an ice accretion control volume facing the airstream; - at least one first electromagnetic (EM) transmitter configured for transmitting EM radiation, at least one first EM detector configured for detecting said EM radiation, and at least one second EM detector configured for detecting said EM radiation, said at least one first EM detector being different from said at least one second EM detector; - the device providing a first optical path for said EM radiation from said first EM transmitter to said at least one first detector in the absence of ice in said control volume; - the device further providing a second optical path for said EM radiation to said at least one second detector in the presence of ice in said control volume, said second optical path being different from said first optical path.
2. The device according to claim 1, the body defining a reference axis associated with the control volume, the reference axis being generally transverse to the airstream.
3. The device according to claim 1 or claim 2, wherein said EM radiation is in at least one of the visible spectrum, ultraviolet (UV) spectrum, infrared (IR) spectrum.
4. The device according to any one of claims 1 to 3, wherein said EM radiation has a radiation wavelength of wavelength 650nm or 980nm.
5. The device according to any one of claims 1 to 4, wherein said control volume is defined by a cutout portion in said body, said cut-out portion comprising an accretion surface facing the airstream connected at one axial end thereof to a first end wall and at another axial end thereof to a second end wall, and wherein said reference axis intersects said first end wall and said second end wall.
6. The device according to any one of claims 1 to 5, wherein said at least one first EM transmitter comprises an optical refracting component.
7. The device according to claim 6, wherein said optical refracting component comprises a prismatic element having a prism apex angle of 30°. 49 254374/ 02490618 04 - 1
8. The device according to any one of claims 1 to 7, wherein said at least one first EM transmitter comprises a respective at least one first optical fiber element for transmitting said EM radiation along a respective first optical fiber axis.
9. The device according to any one of claims 6 to 8, wherein said at least one first EM transmitter comprises a respective at least one first optical fiber element for transmitting said EM radiation along a respective first optical fiber axis, and wherein said optical refracting component is integral with at a free end of said least one first optical fiber.
10. The device according to any one of claims 6 to 9, wherein said optical refracting component is in the form of an optical prism.
11. The device according to claim 10, further comprising a first optical folding component in optical communication with said optical refracting component and said at least one first optical fiber element.
12. The device according to any one of claims 6 to 11, wherein said optical refracting component comprises an optical output surface generally facing towards said second end wall.
13. The device according to claim 12 wherein said optical output surface is tilted with respect to said reference axis such that said first optical path and said second optical path are on different sides with respect to said reference axis.
14. The device according to any one of claims 1 to 13, wherein said at least one second EM detector comprises a respective at least one second optical fiber element for detecting said EM radiation along a respective second optical fiber axis.
15. The device according to any one of claims 1 to 14, wherein said at least one first EM detector comprises a respective at least one third optical fiber element for detecting said EM radiation along a respective third optical fiber axis.
16. The device according to any one of claims 1 to 15, further comprising at least one backscatter EM detector for detecting backscatter radiation originating from said EM radiation within said control volume. 50 254374/ 02490618 04 - 1
17. The device according to claim 16, wherein said at least one backscatter EM detector comprises a respective at least one fourth optical fiber element for detecting said backscatter radiation along a respective third optical fiber axis.
18. The device according to any one of claims 4 to 17, wherein said at least one first EM transmitter is configured for transmitting said EM radiation from said first end wall towards said second end wall, wherein said at least one first EM detector is configured for detecting said EM radiation at a respective first location on said first end wall, and wherein said at least one second EM detector is configured for detecting said EM radiation at a respective second location on said first end wall, said first location being different from said second location.
19. The device according to claim 18, wherein said second end wall comprises a first reflection surface and a second reflection surface, said first reflection surface being configured for reflecting said EM radiation incident thereon from said first EM transmitter towards said at least one first EM detector in the presence of air in said control volume, and said second reflection surface being configured for reflecting said EM radiation incident thereon from said first EM transmitter towards said at least one second EM detector in the presence of ice in said control volume.
20. The device according to any one of claims 4 to 17, wherein said at least one first EM transmitter is configured for transmitting said EM radiation from said first end wall towards said second end wall, wherein said at least one first EM detector is configured for detecting said EM radiation at a respective first location on said second end wall, and wherein said at least one second EM detector is configured for detecting said EM radiation at a respective second location on said second end wall, said first location being different from said second location.
21. The device according to claim 20, wherein said second end wall comprises a first optical input surface at said first location, and a second optical input surface at said second location, said first optical input surface operating to channel said EM radiation incident thereon from said first EM transmitter towards said at least one first EM detector in the presence of air in said control volume, and said second optical input surface operating to channel said EM radiation incident thereon from said first EM transmitter towards said at least one second EM detector in the presence of ice in said control volume. 51 254374/ 02490618 04 - 1
22. The device according to any one of claims 1 to 21, further comprising at least one electromagnetic (EM) system that is configured for transmitting EM energy to said control volume, said EM energy being configured for melting ice that can accrete within said control volume in operation of the device.
23. The device according to claim 22, wherein said EM system is configured for providing said energy in the form of laser energy of wavelength of 1470nm, 1500nm or 1550nm.
24. The device according to any one of claims 22 to 23, wherein said EM system is configured for providing laser energy of intensity between 0.01 W/mm and 0.1 W/mm.
25. The device according to any one of claims 22 to 24, wherein said EM system is configured for providing laser energy of intensity 0.03 W/mm.
26. The device according to any one of claims 22 to 25, wherein said EM system is further configured for directing said laser energy toward said second end wall.
27. The device according to any one of claims 22 to 26, wherein said EM system is configured for directing said laser energy toward along a transmittal direction generally parallel to said reference axis.
28. The device according to any one of claims 22 to 27, wherein said EM system is further configured for directing said laser energy outside of said control volume.
29. The device according to any one of claims 22 to 25, wherein said EM system is configured for directing said laser energy toward along a transmittal direction generally orthogonal to said reference axis.
30. The device according to any one of claims 22 to 25, wherein said EM system is configured for directing said laser energy toward along a transmittal direction towards said control volume having first traversed said accretion surface.
31. The device according to any one of claims 22 to 30, wherein said EM system is further configured for directing said laser energy forward of said control volume.
32. The device according to claim 31, wherein said EM system is further configured for preventing formation of an ice bridge outside of and proximate to said control volume. 52 254374/ 02490618 04 - 1
33. The device according to any one of claims 1 to 32, wherein the device is made from non-metallic materials.
34. The device according to any one of claims 22 to 33, wherein said accretion surface is provided on a front wall of said body, and wherein at least said front wall is transparent and/or translucent with respect to the aforesaid EM energy provided by the at least one EM system.
35. The device according to any one of claims 22 to 33, wherein said body is transparent and/or translucent with respect to the aforesaid EM energy provided by the at least one EM system.
36. The device according to any one of claims 22 to 35, wherein, the device is made from materials transparent and/or translucent with respect to the aforesaid EM energy provided by the at least one EM system.
37. The device according to any one of claims 22 to 35, wherein, the accretion surface is provided on a front wall of said body, and wherein at least said front wall is made from materials transparent and/or translucent with respect to the aforesaid EM energy provided by the at least one EM system. For the Applicants, REINHOLD COHN AND PARTNERS By:
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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IL254374A IL254374B (en) | 2017-09-06 | 2017-09-06 | Device for detecting ice |
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IL254374A IL254374B (en) | 2017-09-06 | 2017-09-06 | Device for detecting ice |
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IL254374A0 IL254374A0 (en) | 2017-12-31 |
IL254374B true IL254374B (en) | 2022-08-01 |
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IL254374A IL254374B (en) | 2017-09-06 | 2017-09-06 | Device for detecting ice |
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Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6010095A (en) * | 1997-08-20 | 2000-01-04 | New Avionics Corporation | Icing detector for aircraft |
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2017
- 2017-09-06 IL IL254374A patent/IL254374B/en unknown
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6010095A (en) * | 1997-08-20 | 2000-01-04 | New Avionics Corporation | Icing detector for aircraft |
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