CN110466779B - Ice crystal detector - Google Patents
Ice crystal detector Download PDFInfo
- Publication number
- CN110466779B CN110466779B CN201910768703.1A CN201910768703A CN110466779B CN 110466779 B CN110466779 B CN 110466779B CN 201910768703 A CN201910768703 A CN 201910768703A CN 110466779 B CN110466779 B CN 110466779B
- Authority
- CN
- China
- Prior art keywords
- ice crystal
- ice
- inlet
- crystal detector
- bar
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000013078 crystal Substances 0.000 title claims abstract description 178
- 239000000523 sample Substances 0.000 claims abstract description 75
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 47
- 230000008859 change Effects 0.000 claims description 33
- 230000008014 freezing Effects 0.000 claims description 21
- 238000007710 freezing Methods 0.000 claims description 21
- 230000004907 flux Effects 0.000 claims description 13
- 230000015572 biosynthetic process Effects 0.000 claims description 12
- 230000003287 optical effect Effects 0.000 claims description 12
- 238000001514 detection method Methods 0.000 claims description 11
- 238000010438 heat treatment Methods 0.000 claims description 7
- 208000033748 Device issues Diseases 0.000 claims description 5
- 230000011664 signaling Effects 0.000 claims description 5
- 230000002093 peripheral effect Effects 0.000 claims description 4
- 230000000875 corresponding effect Effects 0.000 description 4
- 238000004088 simulation Methods 0.000 description 4
- 230000009471 action Effects 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000004519 grease Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000000411 inducer Substances 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
Images
Classifications
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Aviation & Aerospace Engineering (AREA)
- Geophysics And Detection Of Objects (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
The invention relates to an ice crystal detector. The ice crystal detector has an ice crystal collecting probe, a sensing device disposed on an inner wall of the ice crystal collecting probe, and a control device. The ice crystal collecting probe consists of an inlet straight pipe section, an outlet straight pipe section and a tapered section between the inlet straight pipe section and the outlet straight pipe section. The ice crystal collecting probe is simple in structure and can effectively collect ice crystals and supercooled water drops. Ice crystal collection detectors can conveniently acquire icing conditions by means of pressure sensors and/or photoelectric sensors.
Description
Technical Field
The invention relates to aircraft detection equipment, in particular to an ice crystal detector which is used for detecting whether ice crystal icing conditions exist in the air.
Background
Icing conditions encountered by the aircraft in the air include conventional supercooled water droplet icing conditions (water droplet diameter is less than or equal to 50 um) in appendix C of airworthiness clause 14CFR 25, supercooled large water droplet icing conditions (water droplet diameter is less than 500 μm and is called frost hair rain, water droplet diameter is greater than or equal to 500 μm and is called frost rain) in appendix O of 14CFR 25, and ice crystal conditions D in appendix 14CFR 33. The present invention refers to the above appendix C conventional supercooled water droplets and appendix O supercooled large water droplets collectively referred to as supercooled water droplets. When the icing condition contains supercooled water drops and ice crystal icing condition, the icing condition is called as mixed icing condition.
The icing detection can detect the condition that the airplane enters the icing at the early stage, send icing warning information and prompt a pilot to take corresponding actions in time, and is an improvement measure for guaranteeing flight safety.
Supercooled water droplets can cause icing of the aerodynamic surfaces of the aircraft (wing leading edges, nacelle leading edges, etc.), resulting in degraded aircraft stability, lost flight performance, and reduced flight safety margins.
Ice crystal icing conditions exist in the peripheral regions of high altitude convective storms and cannot be detected by the weather radar of the aircraft. When an airplane enters an ice crystal icing condition, ice crystals are rebounded on the surfaces of the airplane body and the engine at low temperature, so that the airplane body cannot be iced, but the ice crystals can enter the engine, and are melted on the blades of the compressor along with the rise of temperature to generate icing, so that the tips of the blades are warped and torn, the thrust loss of the engine is further caused, and accidents such as surging, stalling and flameout occur; and ice crystals can block pitot tubes and total temperature sensor probes, causing altitude and temperature data anomalies, compromising flight safety.
Icing conditions encountered in flight, about 99% of which are conventional supercooled water droplet icing conditions, are typically fitted with an icing detector. The icing conditions of supercooled large water drops, ice crystals and mixed state are about 1%, but the supercooled large water drops and the ice crystals icing conditions cause a plurality of crash accidents in recent years, and gradually attract the attention of the airworthiness authorities, and the legal regulations of the icing conditions of the supercooled large water drops in appendix O of part 14CFR 25 and appendix D of part 14CFR 33 are issued successively for improving flight safety measures. However, at present, there is no case where a supercooled water droplet, ice crystal icing condition or mixed icing condition detection device is actually applied to an aircraft.
Document US 7,104,502 discloses an icing detector with a cylindrical magnetostrictive probe head. When supercooled water drops impact the probe, the vibration frequency of the probe is reduced along with the increase of the icing mass, and an icing signal is sent out after the vibration frequency is reduced to a threshold value. In the icing detector of the type, ice crystals bounce after colliding with the cylinder, and the icing condition of the ice crystals cannot be effectively detected.
Document US 7,014,357 discloses an icing condition detector. Two dry and wet platinum resistor temperature sensors form a bridge in the probe, the voltage difference of different concentrations of supercooled water drops is different, and the icing signal is sent out when the voltage changes to a threshold value. With the detector of this document, ice crystal icing conditions cannot be detected because ice crystals pass through the sensor with the high velocity gas stream without freezing on the temperature sensor.
Similar to US 7,104,502, document EP1533228 also has a magnetostrictive probe head, which integrates a vibrating diaphragm at the bottom of a groove by adding a groove on the support structure. Since the shallow groove in this document is located on the gas flow rising surface, ice crystals bounce off the groove and the probe is not effective in detecting ice crystal freezing conditions.
Document US 7,845,221 discloses an ice crystal detecting device, which consists of two parallel conical tubes, wherein one conical tube 1 is constantly heated, one conical tube 2 is not heated, two pressure sensors respectively measure the pressure of the two conical tubes to calculate the pressure difference, the ice crystal impacts the conical tube 2 to block the conical tube, the pressure difference changes to a threshold value, and an alarm is given out. The defects are that a conical pipe is heated constantly, and the electric power consumption is large.
Disclosure of Invention
In view of the above-mentioned shortcomings of the ice crystal detector in the prior art, the present invention aims to provide an ice crystal detector which can at least replace the above-mentioned various detectors, and in addition, the ice crystal detector of the present invention has a simple structural form and high reliability.
This object is achieved by an ice crystal detector according to the invention. The ice crystal detector comprises an ice crystal collecting probe, a sensing device and a control device, wherein the sensing device and the control device are arranged on the inner wall of the ice crystal collecting probe. The ice crystal collecting probe comprises an inlet straight pipe section, an outlet straight pipe section and a tapered section which is connected with the inlet straight pipe section and the outlet straight pipe section and has a gradually reduced cross section. The diameter of the inlet straight pipe section is larger than that of the outlet straight pipe section. Wherein the sensing device is a pressure sensing device capable of detecting a pressure change at the inlet and/or outlet of the ice crystal collecting probe and transmitting a detected pressure signal. The control device receives the detection signal from the sensing device and signals ice crystal icing when the rate of pressure change is greater than a predetermined threshold.
Preferably, the pressure sensors are arranged at least on the inlet straight pipe section and the outlet straight pipe section.
In one embodiment, the pressure rate of change may be a rate of change of a pressure difference between the inlet and the outlet of the ice crystal collection probe, the ice crystal detector signaling ice formation when the rate of change of the pressure difference is greater than a first predetermined threshold; in another embodiment, it may be the rate of pressure change at the inlet of the ice crystal collection probe, the ice crystal detector signalling ice formation when the rate of pressure change at the inlet of the ice crystal collection probe is greater than a second predetermined threshold.
According to the ice crystal detector, the inlet straight pipe section and the outlet straight pipe section of the ice crystal collecting probe can start rectification on air flow, the reducing pipe arranged between the inlet straight pipe section and the outlet straight pipe section has a suction effect on the air flow, and a large amount of ice crystals can smoothly enter the reducing section. As the internal cross-section of the ice crystal collecting probe is reduced, the collected ice crystals accumulate and plug the bottom of the tapered section. The effect of this is that the pressure P1 in the inducer increases rapidly. Furthermore, it can be understood that, in the case where the collecting probe is not blocked by ice crystals, the pressure difference between the inlet and outlet of the ice crystal collecting probe is in a predetermined functional relationship with the flying speed and the area ratio between the inlet and outlet of the collecting probe, and when the probe is blocked by ice crystals, the static pressure P1 at the inlet section increases sharply, and thus, the rate of change of the pressure difference (P1-P2) between the inlet and outlet of the ice crystal collecting probe also changes sharply. Compared with the method for judging whether the ice is frozen or not only by the pressure change rate at the inlet of the ice crystal collecting probe, the probability of mistakenly generating ice crystal freezing alarm caused by the change of external parameters when the airplane accelerates, climbs or descends can be obviously reduced by the pressure difference change rate between the inlet and the outlet of the ice crystal collecting probe.
Alternatively, ice crystal icing conditions may also be confirmed by sensing light changes within the ice crystal collection probe. In particular, in one embodiment, the sensing means is replaced by a first photosensor located at an end of the tapered section adjacent the outlet straight tube section, the first photosensor forming a first optical path, the control means signalling ice crystal freezing when the first optical path is cut.
Based on the ice crystal collecting probe, in the case that the ice crystal collecting probe collects ice crystals, the ice crystals can be accumulated and blocked at the bottom of the tapered section, at the moment, the first light path is cut off, and the first photoelectric sensor sends a corresponding detection signal to the control device, so that the control device sends an ice crystal icing signal.
According to a preferred embodiment of the invention, the ice crystal detector further comprises a first ice formation bar having an axis substantially parallel to the axis of the ice crystal collecting probe, and a first end of the first ice formation bar is located in the inlet straight tube section and a second end opposite the first end extends at least to the tapered section.
In the above solution, the provided first icing bar is particularly suitable for the embodiment provided with the first photosensor. After the first ice-forming rod is arranged, the part of the tail end of the tapered section is occupied by the first ice-forming rod, so that the effective area of the tail end of the tapered section is reduced, the area ratio of the inlet and the outlet of the ice crystal collecting probe is increased, the ice crystal collecting probe is more beneficial to collecting the ice crystal, and the tail end of the tapered section is blocked.
In order to avoid the reduction of the luminous flux of the first light path sensor due to the first ice forming rod blocking part of the first light path, the first ice forming rod is preferably provided with a through hole for the first light path to pass through.
Preferably, the first icing bar is substantially conical or cylindrical. When the first ice bar is substantially conical, the base of the cone is located at the tapered section; when the first icing bar is approximately cylindrical, the front end part of the cylindrical body, which is positioned at the inlet straight pipe section, is a spherical end, and the diameter of the spherical end is larger than that of the main body part of the cylindrical body.
The first pole that freezes of cylinder, cone shape is the axisymmetric structure, and the first pole that freezes that so sets up can make the flow field remain stable and along the axial equipartition. Supercooled water drops enter the probe along with the air flow, are rectified in the straight pipe section, impact the front end of the first icing rod to be iced, cut off a light path or obviously reduce luminous flux, and then send an icing signal. Especially for the first ice-forming bar of cone configuration, the gap between the first ice-forming bar and the inner surface of the ice crystal collecting probe is gradually reduced along the axial direction of the ice crystal collecting probe, which is more favorable for ice crystal accumulation.
The front section of the first ice-forming rod is located behind the inlet straight tube section (i.e. the first ice-forming rod does not protrude from the inlet straight tube section beyond the ice crystal collecting probe) so that the first ice-forming rod does not disrupt the rectifying action of the inlet straight tube section, which facilitates entry of ice crystals and/or supercooled water droplets into the probe. Preferably, the distance D2 between the first end of the first icing bar and the inlet end of the inlet straight tube section may be set as: d2 is more than or equal to 2R and less than or equal to 4R, wherein R is the diameter of the bottom surface of the cone or the diameter of the spherical end.
According to a preferred embodiment of the present invention, the first ice-forming rod further comprises at least one set of second photosensors, and a distance D1 between a second optical path formed by the second photosensors and the first end of the first ice-forming rod is: d1 is more than or equal to 0.3mm and less than or equal to 0.5mm, and when the luminous flux of the second light path is reduced or cut off, the control device sends out a supercooled water drop icing signal.
The second photoelectric sensor of form can also avoid because of impurity such as dust, grease is infected with on freezing the pole surface, triggers the wrong report and reports to the police when satisfying the precision that can survey the super-cooled water droplet signal that freezes.
According to a preferred embodiment of the present invention, the first ice-making rod is provided with a first through hole substantially perpendicular to the axis at an end of the inlet straight pipe section. The ice crystal detector also comprises at least one group of third photoelectric sensors, and a third light path formed by the third photoelectric sensors can pass through the first through hole. When the light flux of the third light path is reduced or cut off, the control device issues a supercooled water droplet icing signal. Preferably, the first through hole is arranged in a staggered manner with the spherical end, that is, the first through hole is arranged at the rear end of the spherical end.
According to experimental research, the first freezing rod with the spherical end is beneficial to improving the collection rate of supercooled water drops and ensuring that ice crystals splash and are not frozen after being impacted. When the diameter of the supercooled water drops is larger, for example, larger than 100 μm, the supercooled water drops are broken by splashing and frozen at the rear of the spherical head. Therefore, the ice crystal detector is particularly suitable for the supercooled water drop icing condition under the condition by arranging the first through hole at the rear part of the spherical end and the third photoelectric sensor corresponding to the first through hole. The first through hole is arranged on the ice crystal detector, and the first through hole can play a role in boundary layer control, which is beneficial to freezing of supercooled large water drops at the boundary layer, so that a light path is cut off, and an icing signal of the ice crystal detector is ensured.
The invention also provides another form of ice boom. The freezing rod (second freezing rod) is fixed on the peripheral wall of the inlet straight pipe section. And the axially opposite ends of the second ice bar have fairing elements for reducing turbulence which are transparent. The rectifier element has a fourth photosensor therein, which is capable of forming a fourth optical path on the surface of the second ice bar. When the luminous flux of the fourth light path is reduced or cut off, the control device sends out a supercooled water droplet icing signal. Preferably, the main body portion of the second ice bank is a cylinder.
The second icing rod with the cylindrical structure is of an axisymmetric structure, so that the second icing rod can keep a flow field stable and uniformly distributed along the axial direction, and the influence on the icing performance of the second icing rod due to the change of the yaw angle and the attack angle of the airplane is remarkably reduced. And the receiving end and the transmitting end of the fourth photoelectric sensor form a light path along the outer surface of the cylinder through the transparent cavity of the rectifying element, and when the surface is frozen, the light path is cut off, and the ice crystal detector sends out a supercooled water drop freezing signal.
Preferably, one or more layers of the outlet straight pipe section, the inlet straight pipe section and the tapered section can be provided with heating elements at will. The heating element preferably heats the region to a temperature slightly above zero, more preferably 1-2 ℃, thereby avoiding that under certain special conditions, supercooled water droplets may directly impact the outlet straight pipe section to freeze due to the action of pneumatic force and the like and trigger a false alarm of an ice crystal signal. The surface is kept at the temperature of 1-2 ℃, so that supercooled water drops can be prevented from freezing and fly out of the ice crystal collecting probe along with air flow.
According to a preferred embodiment of the present invention, the ice crystal detector further comprises a third ice formation bar and a fifth photosensor located inside the inlet straight tube section, the axis of the third ice formation bar is substantially perpendicular to the axis of the inlet straight tube section, and a fifth optical path formed by the fifth photosensor is located in front of the third ice formation bar. When the light flux of the fifth light path decreases or the fifth light path is cut off, the control means issues a supercooled water droplet icing signal. Preferably, the third ice bar is substantially cylindrical, so as to reduce the impact on the icing performance of the third ice bar due to changes in the yaw and attack angles of the aircraft.
Similar to the concept of the second icing rod, the fifth photoelectric sensor forms a light path on the outer surface of the cylinder of the third icing rod, and when the surface of the third icing rod is iced, the light path is cut off, and an icing signal is sent out.
According to a preferred embodiment of the invention, the taper angle θ of the tapered section is: theta is more than or equal to 60 degrees and less than or equal to 120 degrees.
According to a preferred embodiment of the invention, the cone angle θ is 90 °.
According to a preferred embodiment of the invention, the ratio r of the diameter at the inlet to the diameter at the outlet of the tapered section is: r is more than or equal to 1/3 and less than or equal to 2/3.
According to a preferred embodiment of the invention, said ratio r is 1/2.
According to the ice crystal collecting probe of the above form, it has minimal airflow resistance in the event that ice is not collected.
According to a preferred embodiment of the invention, the pressure variation control means comprise a database storing the first predetermined threshold value and the second predetermined threshold value at each flight speed.
For ice crystal collecting probes with different sizes, under normal flight, the pressure difference change rate between the inlet and the outlet of the ice crystal collecting probe and the pressure change rate of the inlet have corresponding functional relations with the airplane speed, and the functional relations can be obtained through simulation tests or simulation and the like. From this function, an upper pressure change rate limit (first predetermined threshold) and an upper differential pressure change rate limit (second predetermined threshold) can be obtained for each aircraft speed at which the aircraft is not subjected to ice crystal conditions. When the parameters exceed the respective upper limits, it is indicated that the aircraft is subjected to ice crystal icing conditions.
According to a preferred embodiment of the invention, the control device comprises a database storing a first predetermined threshold value and a second predetermined threshold value, both as a function of the angle of attack, of the aircraft, of the sideslip angle and of the temperature, of the flight speed.
In practice, even if no blockage occurs at different aircraft attack angles, sideslip angles and temperatures, the rate of change of the pressure difference between the inlet and the outlet of the ice crystal collecting probe and the rate of change of the pressure at the inlet at the same flight speed change, so that in order to avoid the above factors from influencing the ice crystal detection accuracy, the control device preferably corrects the first predetermined threshold value and the second predetermined threshold value at each flight speed by using the acquired aircraft attack angle, sideslip angle and temperature information. The correction mode can be obtained through simulation test or simulation and the like.
According to a preferred embodiment of the invention, the ice crystal collecting probe is circular or elliptical in cross-section.
An ice crystal detector according to the present invention has an ice crystal collecting probe, a sensing means disposed on an inner wall of the ice crystal collecting probe, and a control means. The ice crystal collecting probe consists of an inlet straight pipe section, an outlet straight pipe section and a tapered section between the inlet straight pipe section and the outlet straight pipe section. The ice crystal collecting probe is simple in structure and can effectively collect ice crystals and supercooled water drops. Ice crystal collection detectors can conveniently acquire icing conditions by means of pressure sensors and/or photoelectric sensors.
Drawings
For a better understanding of the above and other objects, features, advantages and functions of the invention, reference should be made to the preferred embodiments illustrated in the accompanying drawings. Like reference numerals in the drawings refer to like parts. It will be appreciated by those skilled in the art that the drawings are intended to illustrate preferred embodiments of the invention, without in any way limiting the scope of the invention, and that the various components in the drawings are not to scale.
FIG. 1 is a schematic structural diagram of an ice crystal detector according to a first preferred embodiment of the present invention;
FIG. 2 isbase:Sub>A schematic cross-sectional view taken along A-A of FIG. 1 showing an ice crystal collecting probe;
FIG. 3A isbase:Sub>A schematic cross-sectional view taken along A-A of FIG. 1 showing an alternative ice crystal collecting probe;
FIG. 3B shows a schematic cross-sectional view of the ice crystal collection probe in the direction B-B of FIG. 3A;
FIG. 4 is a schematic structural diagram of an ice crystal detector according to a second preferred embodiment of the present invention;
FIG. 5 is a schematic cross-sectional view of a longitudinal central plane of the ice crystal collecting probe of FIG. 4;
FIGS. 6A-6D illustrate schematic structural diagrams of various rectifier elements in accordance with the present invention;
FIGS. 7A-7C show schematic structural views of various rectifying elements along a top view of FIGS. 6A-6D;
FIG. 8 isbase:Sub>A schematic cross-sectional view in the direction A-A of FIG. 1 showing an alternative ice crystal collecting probe.
Detailed Description
The inventive concept of the present invention will be described in detail below with reference to the accompanying drawings. What has been described herein is merely a preferred embodiment in accordance with the present invention and other ways of practicing the invention will occur to those skilled in the art and are within the scope of the invention. In the following detailed description, directional terms, such as "upper", "lower", and the like, are used with reference to the orientation depicted in the accompanying drawings. Components of embodiments of the present invention can be positioned in a number of different orientations, and the directional terminology is used for purposes of illustration and is in no way limiting.
Embodiment mode 1
Fig. 1 shows the general structure of an ice crystal detector 100 according to a first embodiment of the present invention. As shown in fig. 1, an ice crystal detector 100 arranged on the starting surface of an aircraft has an ice crystal collecting probe 110 and a control device 130. Preferably, the ice crystal collecting probe 110 is fixed above the control device 130 by a support rod 120 to protrude from the skin of the aircraft and collect ice crystals, supercooled water droplets, while avoiding exposure of the controller. The support rods 120 are preferably of cylindrical configuration or the like, whereby different collection effects due to aircraft flying at different flight angles of attack may be reduced.
Figure 2 showsbase:Sub>A partial cross-sectional view (i.e.,base:Sub>A portion of the longitudinal center section) along directionbase:Sub>A-base:Sub>A of figure 1, wherein thebase:Sub>A-base:Sub>A cross-section passes through the central axis of the ice crystal collecting probe 110. As shown in fig. 2, the ice crystal collecting probe 110 has an inlet straight tube section 1, an outlet straight tube section 3, and a tapered section 2 connecting the inlet straight tube section 1 and the outlet straight tube section 3 and having a gradually tapered cross section. Wherein the diameter of the inlet straight tube section 1 is greater than the diameter of the outlet straight tube section 3, which is positioned on the windward side of the aircraft during flight.
The ice crystal detector 100 is provided with a first pressure sensor 111 and a second pressure sensor 112 at the inlet straight tube section 1 and the outlet straight tube section 3, respectively, and a first photoelectric sensor 113 at the end of the tapered section 2 (the end close to the outlet straight tube section 3). Each pressure sensor and the photoelectric sensor may be connected to the lower control device 130 in a wired or wireless manner.
In an ice crystal detection method, the control device 130 acquires a pressure change rate of the inlet straight pipe section 1 per unit time Δ t by the first pressure sensor 111. In the event that this rate of pressure change exceeds a first predetermined threshold, the ice crystal detector 100 emits an ice crystal icing signal.
In another ice crystal detection method, the control device 130 obtains the rate of change of the pressure difference between the inlet straight tube section 1 and the outlet straight tube section 3 per unit time Δ t by the first pressure sensor 111 and the second pressure sensor 112, respectively. In the event that the rate of change of the pressure differential exceeds a second predetermined threshold, the ice crystal detector 100 emits an ice crystal icing signal. Compared with the method, the method for detecting the change rate of the pressure difference can greatly reduce the probability of false alarm by detecting the change rate of the pressure difference.
In the third ice crystal detection method, the control device 130 determines whether an ice crystal freezing condition occurs by detecting whether the first light path formed by the first photosensor 113 is blocked or whether the light flux of the first light path is reduced.
Fig. 3 shows a sectional structure of the ice crystal collecting probe 110 provided with the first ice bar 140. The screenshot direction of fig. 3 is the same as the screenshot direction of fig. 2. In a preferred embodiment, as shown in FIG. 3, a first ice formation bar 140 is added to the ice crystal collecting probe 110. The first ice bar 140 is generally cylindrical as shown in fig. 3 or of a conical configuration not shown. The first ice bar 140 has a front end located within the inlet straight tube section 1 and a rear end located in the tapered section 2. Preferably, the distance D2 between the front end of the first ice bar and the inlet end of the inlet straight pipe section is: d2 is more than or equal to 2R and less than or equal to 4R, wherein R is the diameter of the bottom surface of the cone or the diameter of the spherical end; the rear end of the first ice making rod 140 is substantially flush with the rear end of the tapered section 2.
The axis of the first ice bar 140 is preferably set to be parallel to the axis of the ice crystal collecting probe 110, and more preferably, the axes of both coincide, thereby reducing turbulence due to the asymmetrical structure.
When the first ice bar 140 is substantially cylindrical, the front end portion of the cylindrical body located at the inlet straight pipe section 1 is a spherical end, and the diameter of the spherical end is larger than that of the main body portion of the cylindrical body.
Referring to fig. 3A in conjunction with fig. 3B, fig. 3B is a cross-sectional view taken along B-B of fig. 3A. A first through hole 141 is provided adjacent to the ball-shaped end. The first freeze rod 140 is provided with a second photosensor 115 and a third photosensor 114, respectively. Wherein, the distance D1 from the spherical end to the second optical path formed by the second photoelectric sensor 115 is 0.3-0.5mm; the third light path formed by the third photosensor 114 passes through the first through hole 141. After the supercooled water droplets hit the spherical end, they cut off the second light path or reduce the light flux of the second light path, whereby the ice crystal detector 100 signals the freezing of supercooled water droplets. And a third photosensor 114 is provided adapted to detect supercooled water droplets having a diameter of more than 100 μm.
After the first ice bar 140 is disposed, the first ice bar 140 is preferably provided with a second through hole 142 through which the first optical path passes, in which case the center lines of the first optical path and the first ice bar 140 are substantially located on the same plane.
In order to reduce the air flow resistance, preferably, the taper angle θ of the tapered section 2 of the ice crystal collecting probe 110 is set to: theta is 60 DEG-120 DEG, and more preferably, the taper angle theta is 90 deg. The ratio r of the diameter at the inlet and the diameter at the outlet of the tapered section 2 is preferably set to: 1/3. Ltoreq. R.ltoreq.2/3, more preferably the ratio r is set to 1/2.
In order to avoid that supercooled water drops can directly impact the outlet straight pipe section 3 to be frozen due to the action of pneumatic force and the like and trigger the false alarm of ice crystal signals, one or more layers of heating elements can be optionally arranged at the outlet straight pipe section 3, the inlet straight pipe section 1 and the tapered section 2. The heating element preferably heats the inner surface of the ice crystal collecting probe 110 to 1-2 ℃.
Figure 4 shows another ice crystal detector 100 according to the present invention. The ice crystal collecting probe 110 of this embodiment is the same as embodiment 1 of the present invention, and will not be described in detail. The pressure sensors 111 and 112, the photoelectric sensors 113, 114 and 115 and the first icing bar 140 in the ice crystal collecting probe 110 of embodiment 1 can also be selectively disposed in this embodiment, and are not described herein again. Differences in the present embodiment will be described below.
As shown in fig. 4, the outer peripheral wall of the inlet straight tube section 1 is provided with a second icing bar 150. The transparent rectifying elements 151 shown in fig. 6A to 6D and 7A to 7C are provided at both ends of the second icing bar 150. The second ice bank 150 is preferably of cylindrical configuration. The rectifying element 151A, 151B, 151C, or 151D is provided with a fourth photosensor. The fourth photosensor forms a fourth optical path on the cylindrical surface of the second icing bar 150. When the cylindrical surface of the second ice bar 150 is frozen, the ice weakens or cuts off the fourth optical path, and the ice crystal detector 100 sends an ice signal accordingly.
The rectifying element 151 of the present application is not an element for rectifying an alternating current into a direct current. The rectifying element 151 of the present application will be described below with reference to fig. 6A to 6D and 7A to 7C. As shown in fig. 6A to 6D and 7A to 7C, in which fig. 7A to 7C are external contour views of the rectifying element 151 in the top view direction of fig. 6A to 6D, the rectifying element 151 of fig. 6A to 6D may be provided in a configuration having any one of the circular a, elliptical B, and oblong C external contours of fig. 7A to 7C. The outer annular surface of the rectifying element 151 in the horizontal direction has a good streamline structure, thereby reducing the probability of supercooled water droplets freezing on the surface thereof and avoiding other forms of structures of the rectifying element 151 from affecting the sensitivity and accuracy of the fourth photoelectric sensor; while the top of the rectifying member 151 is substantially planar in configuration, whereby ice is easily broken by aerodynamic forces, which is advantageous in keeping the top of the second ice bar 150 clean and reducing its resistance.
Figure 8 shows a third ice crystal detector 100 according to the present invention. Here, the ice crystal collecting probe 110 of this embodiment is the same as that of embodiment 1, and will not be described again. The pressure sensors 111 and 112, the photoelectric sensors 113, 114 and 115, the first icing bar 140 and the second icing bar 150 in the ice crystal collecting probe 110 in embodiment 1 may also be selectively disposed in this embodiment, and are not described herein again. Differences in the present embodiment will be described below.
As shown in figure 8, the ice crystal detector 100 has a third ice bar 160 and a fifth photosensor 116 within the inlet straight tube section 1. Wherein the axis of the third ice bar 160 is substantially perpendicular to the axis of the inlet straight tube section 1. The fifth light path formed by the fifth photosensor 116 is located in front of the third icing bar 160. When the light flux of the fifth light path is reduced or the fifth light path is cut off, the control device 130 sends a supercooled water droplet icing signal.
Preferably, the third ice bar 160 is substantially cylindrical, thereby reducing the impact on the icing performance of the third ice bar due to changes in the yaw and attack angles of the aircraft.
In an embodiment in which both the first freezing bar 140 and the third freezing bar 160 are provided, the first freezing bar 140 and the third freezing bar 160 may be configured as T-shaped freezing bars.
According to the above embodiments, when the ice crystal detector 100 simultaneously detects the ice crystal signal and the supercooled water droplet icing signal, the ice crystal detector 100 emits a mixed icing signal.
Upon detection of an icing condition, control 130 controls each heating element to heat the respective location to remove ice. During this period, the supercooled water droplet icing signal and the ice crystal icing signal are suppressed.
The heating time may preferably be set to 15-30s.
The scope of the invention is limited only by the claims. Persons of ordinary skill in the art, having benefit of the teachings of the present invention, will readily appreciate that alternative structures to the structures disclosed herein are possible alternative embodiments, and that combinations of the disclosed embodiments may be made to create new embodiments, which also fall within the scope of the appended claims.
Claims (20)
1. An ice crystal detector for arrangement on an aerodynamic surface of an aircraft, the ice crystal detector comprising:
the ice crystal collecting probe comprises an inlet straight pipe section, an outlet straight pipe section and a tapered section which is connected with the inlet straight pipe section and the outlet straight pipe section and has a gradually reduced cross section, wherein the diameter of the inlet straight pipe section is larger than that of the outlet straight pipe section; and
a sensing device disposed on an inner wall of the ice crystal collecting probe, the sensing device including a pressure sensor capable of detecting a pressure change at an inlet and/or an outlet of the ice crystal collecting probe and transmitting a detected pressure signal;
a control device receiving the detection signal from the sensing device, signaling ice crystal freezing when the rate of pressure change is greater than a predetermined threshold,
the ice crystal detector comprises an ice crystal collecting probe, a pressure change rate, a pressure sensor and an ice crystal detector, wherein the pressure change rate is the pressure difference change rate between an inlet and an outlet of the ice crystal collecting probe or the pressure change rate at the inlet of the ice crystal collecting probe, and when the pressure difference change rate is larger than a first preset threshold or the pressure change rate at the inlet of the ice crystal collecting probe is larger than a second preset threshold, the ice crystal detector sends out an ice crystal icing signal.
2. An ice crystal detector according to claim 1, wherein the sensing means further comprises a first photosensor located at an end of the tapered section adjacent the outlet straight tube section, the first photosensor forming a first optical path, the control means signalling ice crystal freezing when the first optical path is cut.
3. An ice crystal detector according to claim 1, wherein the pressure sensor is provided at least in the inlet straight tube section and the outlet straight tube section.
4. An ice crystal detector according to claim 2 or 3, further comprising a first ice formation bar having an axis substantially parallel to the axis of the ice crystal collection probe, and a first end of the first ice formation bar being located in the inlet straight tube section and a second end opposite the first end extending at least to the tapered section.
5. An ice crystal detector according to claim 4, wherein the first ice formation bar is substantially conical or cylindrical and
when the first ice bar is substantially conical, the bottom surface of the cone is located at the tapered section;
when the first icing bar is approximately cylindrical, the front end part of the cylindrical body, which is positioned at the inlet straight pipe section, is a spherical end, and the diameter of the spherical end is larger than that of the main body part of the cylindrical body.
6. An ice crystal detector according to claim 5, wherein the first ice-forming rod further comprises at least one set of second photosensors, the second photosensors forming a second light path at a distance D1 from the first end of the first ice-forming rod of: d1 is more than or equal to 0.3mm and less than or equal to 0.5mm,
wherein the control device issues a supercooled water droplet icing signal when the luminous flux of the second light path is reduced or cut off.
7. An ice crystal detector according to claim 5 or 6, wherein the distance D2 between the first end of the first ice-forming bar and the inlet end of the inlet straight tube section is: d2 is more than or equal to 2R and less than or equal to 4R, wherein R is the diameter of the bottom surface of the cone or the diameter of the spherical end.
8. An ice crystal detector according to claim 5 or 6, wherein the first ice-forming bar is provided with a first through-hole at one end of the inlet straight tube section, the first through-hole being substantially perpendicular to the axis, the ice crystal detector further comprising at least one set of third photosensors, and a third light path formed by the third photosensors passing through the first through-hole,
wherein the control device issues a supercooled water droplet icing signal when the luminous flux of the third light path is reduced or cut off.
9. An ice crystal detector according to claim 8, wherein the first through hole is offset from the spherical end when the first ice bar is cylindrical.
10. An ice crystal detector according to claim 2 or 3, further comprising a second ice bar fixed to the outer peripheral wall of the inlet straight tube section, and having flow rectifying elements at its axially opposite ends for reducing turbulence and being transparent, the flow rectifying elements having inside fourth photosensors capable of forming fourth light paths on the surfaces of the second ice bar,
wherein the control device issues a supercooled water droplet icing signal when the luminous flux of the fourth light path is reduced or cut off.
11. An ice crystal detector according to claim 10, wherein the body portion of the second ice formation bar is a cylinder.
12. An ice crystal detector according to claim 1 wherein the outlet, inlet or tapered straight tube sections are provided with heating elements.
13. An ice crystal detector according to claim 2 or 3, further comprising a third ice accretion bar and a fifth photosensor located in the inlet straight tube section, the axis of the third ice accretion bar being substantially perpendicular to the axis of the inlet straight tube section and the fifth photosensor forming a fifth light path in front of the third ice accretion bar,
wherein the control device issues a supercooled water droplet icing signal when the light flux of the fifth light path is reduced or the fifth light path is cut off.
14. An ice crystal detector according to claim 2 or 3, wherein the taper angle θ of the tapered section is: theta is more than or equal to 60 degrees and less than or equal to 120 degrees.
15. An ice crystal detector according to claim 14, wherein the cone angle θ is 90 °.
16. An ice crystal detector according to claim 2 or 3, wherein the ratio r of the diameter at the inlet to the diameter at the outlet of the tapered section is: r is more than or equal to 1/3 and less than or equal to 2/3.
17. An ice crystal detector according to claim 16, wherein the ratio r is 1/2.
18. An ice crystal detector according to claim 1, wherein the control means comprises a database storing the first and second predetermined thresholds at each flight speed.
19. An ice crystal detector according to claim 1, wherein the control means comprises a database storing a first predetermined threshold value and a second predetermined threshold value, each as a function of aircraft angle of attack, sideslip angle and temperature, and flight speed.
20. An ice crystal detector according to claim 1 or 2, wherein the ice crystal collecting probe is circular, elliptical or oblong in cross-section.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910768703.1A CN110466779B (en) | 2019-08-20 | 2019-08-20 | Ice crystal detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910768703.1A CN110466779B (en) | 2019-08-20 | 2019-08-20 | Ice crystal detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110466779A CN110466779A (en) | 2019-11-19 |
| CN110466779B true CN110466779B (en) | 2023-02-21 |
Family
ID=68512001
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910768703.1A Active CN110466779B (en) | 2019-08-20 | 2019-08-20 | Ice crystal detector |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110466779B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112407297B (en) * | 2020-11-19 | 2022-06-17 | 四川探索者航空科技有限公司 | Aircraft icing detection method, system and device |
| CN112550723B (en) * | 2020-12-25 | 2022-04-12 | 华中科技大学 | Super-cooled large water drop icing probe and detector |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1508598A (en) * | 1974-07-09 | 1978-04-26 | Lucas Industries Ltd | Apparatus for indicating ice accretion |
| GB9322442D0 (en) * | 1993-10-30 | 1993-12-22 | Penny & Giles Avionic Systems | Ice detector |
| US6430996B1 (en) * | 1999-11-09 | 2002-08-13 | Mark Anderson | Probe and integrated ice detection and air data system |
| CN103043216A (en) * | 2012-12-04 | 2013-04-17 | 中国商用飞机有限责任公司 | Icing detector |
| CN107200138A (en) * | 2017-05-27 | 2017-09-26 | 成都凯天电子股份有限公司 | Icing signal detecting device |
| CN110077602A (en) * | 2019-05-16 | 2019-08-02 | 中国商用飞机有限责任公司 | Ice crystal detector and mixed state icing detector |
-
2019
- 2019-08-20 CN CN201910768703.1A patent/CN110466779B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1508598A (en) * | 1974-07-09 | 1978-04-26 | Lucas Industries Ltd | Apparatus for indicating ice accretion |
| GB9322442D0 (en) * | 1993-10-30 | 1993-12-22 | Penny & Giles Avionic Systems | Ice detector |
| US6430996B1 (en) * | 1999-11-09 | 2002-08-13 | Mark Anderson | Probe and integrated ice detection and air data system |
| CN103043216A (en) * | 2012-12-04 | 2013-04-17 | 中国商用飞机有限责任公司 | Icing detector |
| CN107200138A (en) * | 2017-05-27 | 2017-09-26 | 成都凯天电子股份有限公司 | Icing signal detecting device |
| CN110077602A (en) * | 2019-05-16 | 2019-08-02 | 中国商用飞机有限责任公司 | Ice crystal detector and mixed state icing detector |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110466779A (en) | 2019-11-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6759962B2 (en) | Inflight ice detector to distinguish supercooled large droplet (SLD) icing | |
| USRE39295E1 (en) | Ice detector configuration for improved ice detection at near freezing conditions | |
| US8462354B2 (en) | Aircraft icing detector | |
| US6269320B1 (en) | Supercooled large droplet ice detector | |
| US7104502B2 (en) | Ice detector for improved ice detection at near freezing condition | |
| CN110466779B (en) | Ice crystal detector | |
| AU2010249314B2 (en) | Detecting ice particles | |
| CN205256681U (en) | Icing condition detection system and aircraft with same | |
| CN102336272B (en) | Icing detector probe and icing detector comprising same | |
| CN106081123B (en) | Ice crystal detector probe and complex icing condition detector comprising same | |
| CN107132278B (en) | Multi-cylinder array icing detection method | |
| US20110147526A1 (en) | Aircraft | |
| WO2020228281A1 (en) | Ice crystal detector and detection method | |
| JP2004534948A (en) | Large supercooled drop ice detector | |
| US9110197B2 (en) | Method and device for the anticipated detection of icing on a runway | |
| US20140257745A1 (en) | Speedometer insenstive to icy conditions and heavy rainfall | |
| US20050230553A1 (en) | Ice detector for improved ice detection at near freezing condition | |
| CN110077602A (en) | Ice crystal detector and mixed state icing detector | |
| CN206876374U (en) | A kind of super-cooling waterdrop ice detection | |
| CN111216899A (en) | Icing detector based on grating optical fiber deformation | |
| CN108357683B (en) | Small unmanned aerial vehicle icing detection method based on airspeed head | |
| CN107200138A (en) | Icing signal detecting device | |
| CN110525664B (en) | Ice crystal detector and detection method | |
| CN110466778B (en) | Icing detector | |
| CN110077601A (en) | Supercooled water drop icing detector and mixed icing detector |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |