WO2019081060A1

WO2019081060A1 - Device and method for determining the air velocity

Info

Publication number: WO2019081060A1
Application number: PCT/EP2018/000487
Authority: WO
Inventors: Ali SHAMSADDINLOU; Zachary WINTER
Original assignee: Rheinisch-Westfälische Technische Hochschule (Rwth) Aachen
Priority date: 2017-10-26
Filing date: 2018-10-25
Publication date: 2019-05-02
Also published as: DE102017009995A1; DE112018004966A5

Abstract

The invention relates to an air velocity measuring device comprising an emitter arrangement (3), by which particles (4) can be emitted in a time-controlled manner, at least one detector arrangement (7) which is spaced apart from the emitter arrangement (3) and by which particles (4) emitted by the emitter arrangement (3) and moved with an air stream (5) can be detected, and an evaluation unit (1) which is designed to determine the velocity of the air stream (5) on the basis of the flight time of the particles (4) over the known length (x) of a measurement path. The invention further relates to a method for measuring the air velocity and to a method for monitoring the flow at the wings of an aircraft.

Description

Apparatus and method for determining airspeed

The invention relates to an air velocity measuring device and a method for air velocity measurement. Such devices and methods are described e.g. used to measure the air velocity relative to an object, e.g. a vehicle, e.g. an aircraft, and more preferably an aircraft or helicopter. For this purpose, it is known to arrange such devices on a vehicle, so that the device is affected by the air. The air speed measuring device according to the invention can thus be used preferably on moving objects in the surrounding air. However, the device can also be used on a stationary object, e.g. on an object in a wind tunnel or a

Wind turbine, e.g. at the nacelle or wing / rotor blade.

In aviation, in particular, precise knowledge of the

Air speed relative to the aircraft in order to ensure an aerodynamically stable behavior of the aircraft.

In the prior art, essentially so-called pitot tubes are known to measure the air velocity. These are based on the principle of

Back pressure generation and measurement of dynamic pressure in a flown and open in the flow direction tube. The problem with this tube is that this is e.g. by ice formation or other external influences before or during a flight and then generate erroneous readings that can lead to a misjudgment of the aircraft behavior. So it is known that such defective Pitot tubes have already led to aircraft crashes.

CONFIRMATION COPY It is therefore an object of the invention

Air speed measuring device and a method for

Provide air velocity measurement, by means of the reliable

Speed of air flow relative to a stationary or moving object, preferably a vehicle, and especially an aircraft such as a vehicle. an aircraft or helicopter can be determined. The invention provides for the application to moving vehicles that a

According to the invention air velocity measuring device is carried with a vehicle, or this is part of the vehicle and the method during operation of the vehicle, in particular during a flight is performed. However, the invention should also be applied to stationary objects, e.g. Wind turbines or objects in wind tunnels a simple and reliable

Open air velocity measurement. Here, a stationary object is understood as being attached to a place of the earth, even if it has moving parts itself, e.g. in a wind turbine is the case.

The object is achieved by an air velocity measuring device comprising an emitter arrangement, with which time-controlled, in particular pulsed, particles can be emitted, in particular subatomic or atomic or molecular particles, preferably charged subatomic, atomic or molecular particles, and at least one detector arrangement spaced apart from the emitter array, in particular at least one in a direction of air flow to the emitter array spaced detector array, with the of

Emitter array emitted and mitbewegte with an air flow particles are detectable and an evaluation unit which is set up the

To determine the speed of the air flow from the time determined by the at least one detector arrangement flight time, which require the particles to cover the known length of a measuring section.

According to the invention, the object of the invention is achieved in that by means of an emitter arrangement, time-controlled, in particular temporally pulsed, particles are emitted be, preferably subatomic, atomic or molecular particles, more preferably charged subatomic, atomic or molecular particles, which are moved with the flowing air from the emitter assembly towards at least one detector arrangement spaced from the emitter array and the time is detected by the at least one detector array, which require the particles to travel a known length of a measurement path.

This measuring section, which cover the particles as they move along in the flowing air, may preferably be arranged between the emitter arrangement and a detector arrangement and / or between two detector arrangements, in particular between two in the direction of flow

Detector arrangements may be formed.

For this it is essential that the length of the distance between the

Emitter array and one or more detector arrays or between two or more detector arrays is known. The respective lengths of the measuring sections are stored, for example, for calculating the speed in the evaluation unit.

The at least one detector arrangement may preferably be set up to generate a detection pulse when the particles reach the detector arrangement, in particular are thus detected by it, e.g. if these are the

Fly through detector array, fly past this or be caught on / in this.

According to the invention is not as in the prior art by the

Air velocity generated secondary effect, such as a dynamic pressure generated, which depends on other factors, such as the tube opening, but the velocity of the air is measured directly by measuring the time, which need moving with the air particles for the return of the selected measuring section. For this purpose, it is provided in the invention with any timed, in particular pulsed operated release of particles a plurality of particles, in particular thus to release a cloud of particles from the emitter assembly.

The evaluation unit, which carries out the calculation of the speed from the time interval of the drive pulse and a detection pulse and / or between two detection pulses, can also be set up here

To generate driving pulse for the emitter assembly. Likewise, this may be provided for this purpose a separate AnSteuereinheit. The evaluation unit can then be supplied with the externally generated control pulse and the detection pulse and / or the two necessary detection pulses in order to determine their respective time interval.

A device based on the measuring principle of the invention is just by generating a particle variety not susceptible to possible icing or other cross-sectional changes in the measuring section, because even with a reduction of the outlet opening of the emitter array or the inlet opening or generally the measuring cross section of the detector array emits and detects particles may be, with any cross-sectional changes do not affect the determined speed, but at most on the number of emitted and / or detected particles, so that only the height of the

Particle Detection indicating signal is changed. However, regardless of its amplitude or intensity, the correct air velocity is always determined from the measured signal, since the change in the cross section does not influence the time of flight of the particles, which may be reduced in number compared to a normal operation.

Thus, according to the invention, it is also possible from the height of the detected signal to draw conclusions on a possible external influence of the measuring path, e.g. by glaciation during flight operation, so that also depending on the signal height of the at least one detection arrangement, e.g. at

Falling below a signal threshold in time countermeasures can be initiated, for example, an active heating of the emitter assembly and / or detector arrangement or in the worst case that an aircraft is driving to the nearest airport.

In general, the device according to the invention may be heatable, e.g. on

Include heating element, in particular to prevent icing or to remove an existing. The invention may also provide in the

Device optionally. By the operation of resulting waste heat to be directed to or in areas to be heated, especially icing sensitive

Areas of the device to keep it ice-free.

As mentioned above, in one embodiment, the invention can provide that the measuring path is formed between the emitter arrangement and one

Detector array.

For example, it may be provided here by pulsed activation of the emitter arrangement to effect the release of particles, preferably of ions, that is to say charged atoms or molecules, from the emitter arrangement. Pulsed driving of the emitter array initiates a time measurement which is terminated when the particles emitted by the emitter array have a, e.g. reach a single detection arrangement and the arrival there detected by the detection arrangement and through this a corresponding

Detection signal is generated.

By measuring time, the time of flight is known, which required the particles to the known measuring distance between emitter and

To fly through detector array, so that in this way the airspeed of the particles and thus the air velocity can be calculated according to the relationship speed = measuring distance / time of flight.

The invention may also provide for forming the measurement path between two or more detector arrays. Again, a number of particles, in particular a cloud of particles discharged by driving the emitter assembly from this and out with the air flow to the first detection arrangement, which indicates the arrival by a first detection signal. The invention can provide here that the particles at least one in

Flight direction fly through the first detection arrangement or fly past it and hereafter be detected by at least one second detection arrangement at least one more time, so at least a second detection signal is generated. For this purpose, a time measurement can be started by the first detection signal, which is terminated by a second detection signal.

By measuring the time interval of the detection signals of successive detection arrangements and their known distance, in turn, the airspeed of the particles between the detection arrangements and thus the air velocity can be determined according to the aforementioned relationship.

The above-described procedures can also be combined so that a first measurement of the air velocity between the emitter arrangement and the first detection arrangement can be checked by means of at least one further measurement of the air velocity between two successive detection arrangements.

Preferably, especially for aerodynamic reasons, are the

Flowed through detection arrangements of the air and are thus flown through by the particles. Therefore, such detection arrangements represent a very low air resistance. Detection arrangements can also be designed such that the air and the particles moved with it flow past the detection apparatus. This also offers a low air resistance and preferably an influence of the detection device on the particle cloud is avoided.

However, it can also be provided that a detection arrangement represents a baffle surface, which is streamed by the air, through which the particles are captured. Such a baffle can thus be part of a measuring sensor, with which the arrival of the particles is detected.

For example, in one possible embodiment, the invention can provide uncharged particles, in particular atoms or molecules of a known mass, from one Emitter assembly in the air flow release. Preference is then given to emitting those particles which do not occur in the air, whose velocity is not measured, or only to a small extent at most. For example, the emitter assembly may be connected to a gas reservoir of such particles, and a gas valve of the emitter assembly may be pulsed to discharge a number, especially a cloud, of such particles from the emitter assembly.

A detector arrangement suitable for such particles may e.g. comprise at least one mass spectrometer. The invention may provide a

Mass position, which corresponds to the mass of the particles used in the

Mass spectrum in time to the occurrence of a detection signal too

monitor. The time interval between the drive signal of the

Emitter arrangement and the detected signal again corresponds to the flight time.

It is preferred to use charged particles, e.g.

subatomic charged particles such as e.g. To use electrons or atomic or molecular ions and produced in the emitter assembly such charged particles and controlled to release or to let already existing charged particles of a particle source present in the emitter assembly pulsed escape from the emitter array.

For example, it may be provided that the emitter arrangement comprises a continuously emitting particle source and a timed particle trap, wherein the emission of .mu.s by an activation of the particle trap

Particles from the emitter assembly is effected, in particular pulsed effected.

For example, the particle source can emit electrons, for which the

Particle source, for example, a glowing element, preferably may comprise a glowing wire from which electrons emerge. Such a glowing element may be part of an electrode arrangement between which an electrical potential is applied to apply the work function of the electrons, that is, the energy necessary to cause electrons to emit from the element. Alternatively, the particle source can also emit charged particles resulting from radioactive radiation decay, in particular charged alpha particles or even electrons (beta particles). For this, the

Particle source through a supply of material of a radioactive emitter,

in particular alpha emitter, e.g. by americium 241.

The controlled, in particular pulsed discharge of charged particles, e.g. The above, can be realized by a particle trap realized in the emitter arrangement.

For example, For example, a particle trap may be formed by a timed electrical and / or magnetic field, e.g. that is, by spaced electrodes or by at least one electromagnet. So can with such

Particle traps e.g. causes only at the time of pulsed

Control the particles can pass through the particle trap and otherwise be captured, causing you at the exit of the

Emitter arrangement be prevented.

Particularly in the case of the use of electrons, which are very light particles, the particle trap can comprise an electric field that is formed between two or more electrically controllable electrodes. For example, For example, the electrodes emitted by the particle source may be deflected and captured in an on-electric field. By a pulsed elimination of the electric field, a temporal window is created, in which the

Electrons can leave the emitter assembly, so that an electron cloud is formed, which is discharged from the emitter assembly and is guided with the air flow to the detector assembly.

In general, and in particular with comparatively heavier charged particles, eg charged alpha particles, the invention can also provide for realizing the particle trap with a pulsed magnetic field. For example, if the magnetic field is not turned on, the particles emitted by the particle source are trapped. By pulsed switching a magnetic field that is traversed by the particles may be pulsed to deflect a number of particles, eg alpha particles, through the then acting Lorentz force and thus be discharged from the emitter array, after which the particles are entrained with the airflow. The arrangement has the advantage that when using a radioactive source that does not emit exclusively alpha particles, the uncharged radioactive particles or even electrons are always trapped.

Alternatively, the invention may also provide that the emitter assembly comprises a pulsed emissive particle source. For example, For example, a glow element may be pulsed to emit electrons for emission. It may also be provided that the emitter arrangement comprises a pulsed driven light source, e.g. a laser, in particular a laser diode comprises, are triggered with the pulsed on the effect of the photoelectric effect electrons from a lighted element. With such a design of the emitter arrangement, a particle trap can be dispensed with.

The invention may provide, particularly preferably in the abovementioned particle types, that the particles can be emitted into the air stream perpendicular to the direction of airflow by means of the emitter arrangement. For example, For example, the emitter arrangement can be arranged offset to the air flow perpendicular to the direction of air flow, in particular under a surface of the device

be arranged receding, which is overflowed by the air flow parallel to the surface.

This has the advantage that the particles, even if they are with one

Airspeed leave the emitter assembly, the

Velocity vector of this airspeed is oriented perpendicular to the direction of the air flow to be measured and thus does not distort the air velocity measurement.

In the application of the device to an aircraft, e.g. the

Emitter assembly be positioned within the wing of the aircraft and the Emit particles perpendicular to the wing surface out of the wing.

Generally, the emitter assembly may be under a surface of a

Carrier element may be arranged on / in which also at least the

Detector arrangement is arranged. Such a carrier element may e.g. Part of a housing wall of an object relative to which the air velocity is to be measured.

The invention may provide in this application and also with general validity that the discharge of the particles from the emitter array, although perpendicular to a surface in parallel flow over the air flow, e.g. the wing surface or the surface of a support element takes place, but not in the plane of this surface, but at a distance from the surface, in particular so as to avoid a falsification of the speed measurement by the near-surface boundary region of the flow, where the

Flow rate decreases.

Thus, e.g. Also, the emitter array may be disposed at least partially below the surface of a wing of an aircraft or other carrier element, but the emission opening of the emitter array from which the particles exit into the air stream is positioned at a distance from the surface. In particular, this distance can be greater than 5 cm.

In particular, in conjunction with one of the foregoing embodiments, to dispose the emitter assembly at least partially below the surface of a wing of an aircraft or other support member, but also independently thereof and of general validity, it may provide the invention, the at least one detector array perpendicular to

Arranged air flow direction to the air flow to arrange, in particular recede under a surface of the device to be arranged, which is overflowed by the air flow parallel to the surface. It may be the same surface of a support element, under which the emitter assembly is arranged. It can therefore also be provided to arrange the detector arrangement receding below the surface of a wing, fuselage or another surface of an aircraft or carrier element of the device.

In this arrangement, the particles are thus preferably detected in the flyby of the detector array. For example, For this, the detector can monitor / evaluate a physical quantity which changes as the particles fly by, e.g. a capacitance, an electric or magnetic field. The particles passing by thus induce an observable effect in the detector arrangement, preferably without being influenced by the detector arrangement itself.

In another embodiment, the invention may also provide that the

Emitter assembly is traversed by air and with the emitter assembly

Ingredients, e.g. Atoms and / or molecules of the air of the air stream are timed ionizable. For example, the emitter arrangement can flow through this air

controllable electrode assemblies include. An emitter arrangement of this type is preferably permeable in the direction of the air flow to be measured. For example, For example, the emitter arrangement may be formed as a tubular element that is permeated by the flow. The flow is e.g. through a couple of

Led electrodes that may be arranged in the tubular member. By applying a high voltage pulse, in particular more than 5 kV, a cloud of ionized air can be generated, which is carried along with the air flow according to its original direction and can be detected with a detection arrangement.

However, the invention may also provide for the use of other ionized air generators in such an emitter arrangement.

A detection device used in the device according to the invention or several thereof is selected as a function of the one to be detected

Particles. As mentioned above, in the case of uncharged particles, it may be provided that the at least one detector arrangement comprises at least one mass spectrometer which is tuned to the mass of the particles used.

When using charged particles leaving the emitter array, the invention may provide that the emitter array at least one

Coil element comprises, through which the emitted particles can be passed with the air flow, in particular wherein the at least one

Coil element surrounds an air-flow pipe. Such a coil element may e.g. be formed of only a single circular winding or by several.

The charged particles passing through the at least one coil element represent a pulsed current which induces an induced current

Voltage in the coil element leads, which is detectable as a detection signal. From the time interval of the induced voltage signal to the drive pulse, the release of the charged particles from the

Emitter arrangement causes the time of flight and from this according to the aforementioned relationship, the airspeed. By several spaced apart with a known distance coil elements, the possibility described above, the air velocity between two

To measure detector arrays.

In general, a plurality of detector arrangements in a common

Housing may be arranged, e.g. is arranged on a support element.

The invention may also provide that the detector arrangement comprises at least one electrically conductive baffle. The impact of the charged particles on this baffle surface results in a charge increase on the

Baffle. The time interval of the charge increase after the triggering pulse which releases the charged particles from the emitter assembly, in turn, represents the time of flight from which the air velocity can be calculated. In this embodiment, the invention can provide the baffle after each Measurement, or to unload each re-release of charged particles from the emitter assembly.

A detector arrangement may also comprise an electrode arrangement of at least two electrodes, between which an electric field is generated. The electrodes may preferably be arranged so that the air can flow between them. Through the field, the charged particles are drawn onto one of the electrodes, and can thus be detected depending on the evaluation as a current and / or voltage pulse.

It can also be provided that a detector arrangement comprises a plurality of particle detectors distributed in space. In particular, these can

Particle detectors have a spatial distribution in one or more planes perpendicular to a connection direction between an emitter array and the detector array. For example, The particle detectors may form an annular configuration, preferably at the same angular distance from each other. The particle detectors may e.g. be arranged inside and / or outside on the circumference of a tube through which flows through the air or outside on the circumference of a pen flowing around the air. It is thus also possible to detect three-dimensional velocity profiles and / or to reliably detect velocities, even if the distance direction between emitter arrangement and detector arrangement does not correspond exactly to the direction of air flow.

An emitter arrangement, in particular if it is not under an air-overflowed surface and / or one or more detector arrays can each be arranged in a housing whose outer flow around the housing walls in the form of streamlined, so in particular

aerodynamically formed, in particular, such a housing may be formed drop-shaped in cross-section parallel to the flow direction of the air.

When measuring the time interval between a preferably electrical drive pulse for releasing particles from the emitter arrangement and a detection signal, it is preferable to take into account that the drive pulse, in particular has a non-negligible pulse width, as described above, a plurality of particles is released and thus a cloud of particles is formed, which inevitably has an expansion,

in particular, an expansion that is due to charged particles due to

Repulsion effects during flight time may increase. A detection signal will thus have a given signal level and a signal width, in particular because not all particles are detected exactly at the same time.

Here, the invention may provide for the time between a selected edge, e.g. the rising edge of e.g. rectangular drive pulse and a predetermined relative signal level, e.g. 50% of the signal height or even 100% of the signal height of the detection peak, ie the maximum of the

To measure detection peaks. In the case of accumulation of charge on a baffle plate or a pair of capacitors, so can the exceeding of a

predetermined limit charge are detected, in particular based on the timing is stopped.

For example, can be determined by adjustable Schmitt trigger, at which signal level, the timing starts at the drive pulse and ends at the detection pulse.

Essentially, however, it should be stated here that the length of the measuring path is many times greater than the extent of a particle cloud, so that the signal shape of the drive pulse and the detection pulse, in particular their width, and the start and end of the time measurement defined therein no harmful falsification of the time measurement results. Preferably, measuring distances are chosen so that they are greater than 1 mm, more preferably greater than 1 cm, more preferably greater than 5 cm, even more preferably greater than 10 cm. Drive pulses may have, for example, a repetition frequency of greater than 1 Hz, preferably greater than 100 Hz, more preferably greater than 1 kHz, and even more preferably greater than or equal to 10 kHz. All possible embodiments of the invention can provide that the emitter arrangement and the at least one detection arrangement are stationary on a stationary or moving object, eg a vehicle, in particular

Aircraft are attached, e.g. immovable on and / or under the wing or fuselage or even on a nacelle or a rotor blade / wing one

Wind turbine. In this case, the emitter arrangement and the at least one detector arrangement are preferably spaced apart in one direction, which the

Longitudinal direction of the respective object, e.g. corresponds to the hull of the vehicle or the nacelle of the wind turbine.

It may happen, especially in flight mode or by changing wind direction even in stationary objects, that air flows are not exactly parallel to the object extension, e.g. Humpferstreckung present, which can lead to a distortion of the measurements, especially if the

Device according to the invention is rigidly mounted on the object in accordance with its longitudinal axis.

In a development of all possible embodiments, the invention can provide that the device comprises a carrier element on / in which the

Emitter arrangement and the at least one detector arrangement in one

common rectilinear extent are arranged one behind the other, wherein the carrier element comprises at least one tail, in particular which is designed as a standing up from the support member fin and the

Carrier element is rotatably hinged to a base member, in particular the articulation point is arranged in the air flow direction in front of the emitter assembly, preferably also on the common extension line.

Due to the aerodynamic effect on the guide element, the air flow itself causes the guide element to generate a force on the carrier element with which the carrier element is rotated around the articulation point into the flow in such a way that it runs parallel to the rectilinear extent between the emitter arrangement and the at least one detector array is oriented. As a result, thus the device according to the invention itself correct to always make the speed measurement parallel to the air flow.

According to the invention, the base element against which the support element rotates may be part of any object, e.g. of an aircraft or

ground moving vehicle or even a wind turbine, e.g. the gondola or a wing. In particular, in an aircraft that can

Base member may be formed by the wing or a part thereof opposite the then the support member can rotate.

Furthermore, the invention can provide that the carrier element is guided with a space spaced from the articulation area in an arcuate guide groove. In addition to the guide, the position of the carrier element in the guide groove can be detected by sensors.

It is also possible to measure the rotational position of the carrier element relative to the base element in or at the articulation point, e.g. through a

Angle encoder. In such a case, the guide can be omitted in a groove.

In addition to a safe guidance during the rotation but also independently of this, the optional sensory measurement of the position of the support element relative to the base element, a deviation of the extent of the object, e.g. the aircraft fuselage longitudinal extent of the air flow direction

be detected metrologically.

Depending on the measured values, the object extension can thus be corrected, in particular the aircraft fuselage longitudinal extension, e.g. be aligned by controlling the pilot or by correcting the autopilot control, parallel to the air flow, in particular such that a deviation of the

Carrier element is reduced from a desired position.

In general, and therefore also detached from the aircraft application, the wind direction relative to the device can be determined by the rotational position measurement Basic element to be determined. For example, the orientation of another device carrying or receiving the base member may be relative to

be aligned measured wind direction.

For example, Thus, the rotor blades or the gondolas of wind turbines can be aligned relative to the measured wind direction, in particular wherein the wind turbines are set in operation and / or out of operation depending on the measured wind speed.

Particularly in the case of aircraft, the invention can provide for an aircraft to have on the wings pairs of two devices of the type according to the invention, which face one another on the wings above and below. It is thus possible by means of such a device to measure the air velocity above and below at least one wing of the aircraft. For example, can at

Exceeding a predetermined speed difference between the air velocity above and below the wing then a warning is signaled, e.g. which indicates the pilot an impending stall on the wing or too low buoyancy.

It may also, e.g. Instead of a warning or in addition to this, an automatic intervention in the control of the aircraft are made, in particular causes the measured speed difference is reduced.

In one possible embodiment of the invention, it may also be provided that the emitter arrangement at the tip region of one of the air flow

arranged to flow on / flowed pin is arranged, in particular its

Longitudinal extension direction is at least substantially parallel to the air flow, wherein the at least one detector array spaced from the tip region is arranged annularly in the circumferential direction of the pin around the pin surface around.

Here, preferably, the tip portion of the pin can be formed tapered, in particular wherein the emitter assembly on / in the maximum tapered beginning of Tip area is arranged. There is also the possibility that the at least one detector arrangement is subdivided in the circumferential direction into a plurality of detectors, in particular equiangularly spaced. This opens up even with this constructive design of the device as a pen the ability to detect three-dimensional velocity profiles or secure

Speed measurement, if the donor extension is not exactly parallel to the air flow direction.

In a preferred embodiment, the pin may be hollow, thus in effect forming a tube, wherein the emitter assembly is arranged in the tip region, in particular in / on the tapered tip region, around a flowed through by the air flow opening of the hollow pin around. More preferably, the hollow pin may include in its interior a dynamic pressure sensor or the hollow pin is part of a pitot tube.

With the device, e.g. also the measuring principles of a Pitot tube and he invention are combined.

Embodiments of the invention are described below with reference to FIGS.

FIG. 1 illustrates the basic principle of the invention. In this embodiment, a control pulse 2, in this case a square pulse 2, is generated by means of an evaluation unit 1. In general, drive pulses 2 can preferably be generated periodically repeating, so that the measurement method is likewise carried out periodically.

By the drive pulse 2, an emitter assembly 3 is driven, which is thereby caused, a number of particles 4, preferably charged

Release particles 4, e.g. Electrons or alpha particles, or neutral / charged atomic or molecular particles.

With the air flow 5, the particles 4 according to the arrows 6 to

Detector arrangement 7 moves and generate at the detector assembly 7, a pulse-shaped detection signal 8, which is the evaluation unit 1 is supplied. The detection signal 8 is here also visualized as a rectangular pulse, but it can also be a different pulse shape, such as a Gaussian form. The square-wave pulse on which the evaluation is based can also be formed, for example, by a Schmitt trigger logic from a pulse of another pulse shape. In principle, any pulse shape of the detected pulse 8 may be subject to evaluation.

The evaluation unit 1 determines that the detected pulse 8 has arisen a time Δί after the drive pulse 2, and accordingly this time Δt corresponds to the time of flight of the particles 4 between the emitter arrangement 3 and the detector arrangement 7. The distance x between them is known to the evaluation unit, so that the velocity v is calculated by the relationship ν = χ / Δί. this

Speed value v, the evaluation unit 1 can communicate to the outside, e.g. Show.

FIG. 2 shows schematically a possible realization of the device in a plan view. Visible is a support member 9, on or in which the

Emitter array 3 and also at least one detector unit 7 is arranged. By the air flow 5 are again not shown here particles according to the arrows 6 after release from the emitter assembly 3 to

Detector assembly 7 moves and detected there. FIG. 3A shows these

Execution in a side view and illustrates that the emitter assembly 3 in the support member 9, in particular under the surface can be arranged. Here particles 4 are released perpendicular to the surface and thus also perpendicular to the air flow 5 from the emitter assembly 3 in the air flow.

The embodiment shown in Figure 2 has a flow direction in front of the

Emitter assembly lying pivot point 10, around which the support member 9 can rotate, at least in a predetermined angular range, e.g. plus / minus 20 degrees or 30 degrees.

The rear end 9a of the support element 9 in the flow direction is guided in this embodiment in a groove 11, for example by a in the groove from the bottom the basic element 9 projecting pin. The groove 11 can in a

Base element 12 may be arranged, on which also the articulation takes place at the articulation point 10. For example, may be the basic element 12 of the wings of a

Airplane or a surface area of the housing of any object

On the support member 9 is upwardly projecting into the air flow 5 a fin 13, which serves as a tail and automatically aligns the carrier element 9 and arranged thereon emitter array 3 and detector array 7 parallel to the air flow 5. Compared to a desired position, which is visualized by a dashed line 14, this results in a

Angular deviation a.

The angular deviation α can be detected, e.g. by a in the

Guiding 11 realized sensor or by a sensor that detects the angle α in the pivot point 10. On the basis of the measured value of the angular deviation, e.g. to intervene in the control of a vehicle, in particular of an aircraft, to reduce the angular deviation or the orientation of any other device may be changed, in particular these are turned into the wind.

Because here the detector assembly 7 protrudes into the air flow over the surface of the carrier element 9, the housing of the detector assembly

streamlined, in particular so aerodynamically formed here in

Cross-section substantially drop-shaped.

Figures 3B and 3C show different embodiments of

Detector assembly 7 in the direction of air flow. According to FIG. 3B, the detector arrangement 7 is impermeable to the flow of air. The flowed-on surface of the detector arrangement 7 can form a baffle surface on which the particles 4 impinge and are thereby detected, for example by a charge accumulation on the baffle surface, if they are charged particles. According to FIG. 3C, the detector arrangement 7 is permeable to the air flow.

For example, the detector assembly 7, a tube 7 a, which is flowed through. At least one sensor may be arranged on the inner wall of the tube 7a or around it, in order to detect the arrival, in particular the flying, of the particles.

FIGS. 3B and 3C also illustrate that the emitter arrangement 3, in particular its outlet opening perpendicular to the air flow 5, can be wider than the inlet opening or impact surface of the detector unit 7. Particle clouds can thus be generated which are wider than the inlet opening or impact surface.

The respective basic element and the articulation at this is not shown in the figures 3, but may be present. It can also be provided that the device with the carrier element 9 shown, however, is formed without an articulation. FIG. 4A shows the articulation point 10 between the base element 9 and a basic element 12 shown symbolically by dashed lines.

FIG. 4A furthermore shows a modification in which the emitter arrangement 3 is also positioned above the surface of the carrier element 9 and thus the

Emitter assembly 3 is flowed through by the air 5. Particles 4 can be released in the emitter assembly 3 and carried with the air stream 5 to hit the detector assembly 7. Emitter arrangement 3 and detector arrangement 7 can each have an air-flow-through pipe 3a or 7a according to FIG. 4B. The respective outer casing shapes may be the same in both arrangements 3.7.

Figure 5 shows an embodiment of a possible emitter arrangement 3, e.g. one of Figure 4A. The air flowed through pipe 3a in the housing of

Emitter assembly 3 comprises an electrode assembly having electrodes 3b between which an electric field can be pulsed with voltage supply 3c to pulsatically pulse air molecules or atoms in the flowing air. The emitter assembly 3 of this type thus generates charged Particles directly from the air flowing through, then with a

Detector arrangement can be detected.

Figure 6A shows an emitter assembly 3 recessed beneath an overflow surface 15, e.g. the surface of a wing or a carrier element of Figures 2 to 4.

The emitter assembly 3 comprises a recess 3b in which an electron-emitting, e.g. glowing element 3c is arranged, which is energized for this purpose by means of a power supply 3d. The power supply can be operated pulsed.

According to Fig. 6B, e.g. in the arrangement according to FIG. 6A, an electrode arrangement 3d can be arranged around the electron-emitting element 3c, with which an electric field E can be generated. The electrodes may be e.g. be formed by permeable networks. By field E, e.g. the

Work function of the electrons are applied so that the electrons are released from the element 3c and captured directly by the electrodes 3d. The electrodes 3d thus form an electron trap, so that when the field is switched on the electrodes can not leave the emitter arrangement 3.

The field E between the electrodes 3d can be switched off pulsed. The already released electrons 4 are then no longer captured, but can leave the area of the electrodes 3d and out of the

Emerge emitter assembly 3, according to Figure 6A in a direction 16 perpendicular to the flow direction 5 of the air.

FIG. 6C shows a design of an emitter arrangement 3 as a pulsed one

An electron source in which by means of a pulsed laser diode 3g, an electron-emitting element 3h illuminated and thereby the work function of the electrons 4 is applied. The triggered electrons 4 can then leave the emitter assembly 3 in the direction of the arrows 16 and be carried along with the air stream 5. FIG. 7 shows an arrangement in which the emitter arrangement 3 comprises a radioactively decaying material supply 3e which emits charged alpha particles, as well as optionally gamma radiation. In general, it can also be provided that the emitter assembly has a shield against the emission of radiation, if it is based on the particle generation by radioactive decay. For example, the emitter assembly or at least the stockpiled therein

Material supply and / or the area of a particle trap have a lead jacket.

A pulsed magnetic field can be generated by means of a magnetic field that is visualized by a symbolically represented electromagnet arrangement 3 f, whereby a Lorentz force acts on the moving alpha particles 4 during the turn-on time, which are thereby deflected out of the emitter arrangement and these according to the arrows 16 Leave perpendicular to the air flow 5 and then carried along by this.

FIG. 8 visualizes a possible embodiment of a detector arrangement 7. The latter comprises an air-flow-through tube 7 a, which is surrounded by a coil 7 b. The charged particles 4, as they fly through the tube 7b, constitute a time-varying current which leads to an induced voltage in the coil 7b and represents the pulse-shaped detection signal. The dashed lines 7c symbolize an electrode arrangement which serves to draw charged particles 4 onto one of the electrodes 7c and thereby detect them. The

Electrode assembly 7c is to be understood as an alternative to coil 7b, but shown for simplicity in the same Figure 8. The illustrated dashed lines 7c may also symbolize a mass spectrometer as another

Alternative pose.

According to FIG. 9, the flowed-on surface 7c of the detector arrangement can form a baffle surface 7c, against which the charged particles 4 impinge, thereby leading to a charge accumulation on the baffle surface 7c, which can be detected. In the above embodiments of Figures 8 and 9 are the

Detector elements 7b and 7c accordingly electrically conductive with the

Evaluation unit connected.

FIG. 10 shows an embodiment of a detector arrangement 7 with two

Detector coils 7b, which also as two detector arrays in one

common housing can be understood. The charged particles 4 pass through the air flow 5 in succession to both coils 7b and thus generate induction voltage pulses that are temporally separated according to the air velocity and the distance x. With the knowledge of the distance x, it is thus possible to calculate back to the velocity of the air flow over the measured time interval of the pulses. Both coils 7b are connected to the

Evaluation unit connected, which calculates the speed.

Figure 11 shows an embodiment in which the emitter assembly 3 and the

Detector assembly 7 are each arranged receding below the surface of an object, relative to which the air velocity is to be determined. With the evaluation unit 1, which is connected to both arrangements 3, 7, the time interval between the generation and the detection of the cloud of particles 4 is determined.

FIG. 12 shows a development of FIG. 11 in which two

Detector assemblies 7, as well as the emitter assembly 3 are arranged receding below the surface of an object, but here with the

Evaluation unit 1, the time interval between the detections of the particles 4 is determined at the two detector units. Therefore, the evaluation unit is preferably connected here only to the detector units 7.

FIG. 13 shows an embodiment in which the emitter arrangement is arranged on the tapered tip region 17a of a pin 17 which is streamed by the air. At this point, particles 4 are generated with the emitter arrangement 3, which with the air flow along the lateral surface of the pin 17 to two here

Detector assemblies 7 are moved and detected there. Here is am Example of the second detector assembly 7 shown that this can be divided in the circumferential direction into a plurality of particle detectors 7a, each of which independently detect the particles and thus contribute to a spatial spatial resolution of the measured air velocity.

According to Figure 14, the pin 17 is hollow, i. designed as a tube. The

Emitter array 3 is located at the tapered tip area 17a, e.g.

annularly arranged around an opening 17b of the pin 17 around.

Detector assemblies 7 are again arranged as in Figure 13 outside the pin 17 annularly in the circumferential direction. Again, one can

Detector assembly 7 include a plurality of particle detectors, as shown in Figure 13.

In an air velocity measurement, the particles 4 are not only moved along the outside of the pin and detected by the detector assemblies 7, but also air penetrates through the flowed-17b into the interior of the pen

17 and generates there a back pressure, in addition to the dynamic pressure sensor

18 can be measured at the closed and preferably angled end of the tubular pin.

Thus, here the principle of the invention is combined with the measuring principle of a Pitot tube.

Claims

claims

An air velocity measuring device comprising a. an emitter arrangement (3) with which time-controlled particles (4) can be emitted, in particular subatomic, atomic or molecular particles (4), preferably charged subatomic, atomic or molecular particles (4) are emissable and b. at least one spaced from the emitter assembly (3)

Detector assembly (7), in particular at least one in a direction of air flow (5) to the emitter assembly (3) spaced detector assembly (7), with the emitted from the emitter assembly (3) and with an air flow (5) mitbewegte particles (4) are detectable and c , an evaluation unit (1) which is set up to determine the speed of the air flow (5) from the time of flight of the particles (4) over the known length (x) of a measuring path.

2. Apparatus according to claim 1, characterized in that the

Measuring section is formed between the emitter assembly (3) and a detector assembly (7) and / or between two or more

Detector arrangements (7).

3. Device according to one of the preceding claims, characterized

in that the emitter arrangement (3) is continuous

comprising emitting particle source (3c, 3e) and a time-controlled particle trap ((3d, 3f), wherein the emission of particles (4) from the emitter assembly (3) can be effected by driving the particle trap (3d, 3f).

4. Apparatus according to claim 3, characterized in that with the

Particle source (3c) electrons (4) are emissive, in particular the Particle source (3c) comprises a glowing element (3c), preferably a glowing wire from which electrons (4) emerge.

5. Apparatus according to claim 3, characterized in that the

Particle source (3e) is formed by a radioactively decaying material supply, preferably by a material supply of an alpha emitter, are charged with the charged particles (4), in particular charged alpha particles or electrons.

6. Device according to one of the preceding claims 4 or 5, characterized

in that a particle trap (3d, 3f) is formed by a time-controlled electric and / or magnetic field.

7. Device according to one of the preceding claims, characterized

in that the emitter arrangement (3) comprises a pulsed emitting particle source, in particular a pulsed illuminated element (3h), from which electrons (4) can be triggered via the photoelectric effect.

8. Device according to one of the preceding claims, characterized

characterized in that by means of the emitter arrangement (3) the particles (4) are perpendicular to the air flow direction in the air stream (5) are emissive, in particular the emitter assembly (3) perpendicular to the air flow direction to the air flow (5) is arranged offset, in particular under a surface (15 ) is arranged receding the device, which is overflowed by the air flow (5) parallel to the surface (15).

9. Device according to one of the preceding claims, characterized

characterized in that the at least one detector arrangement is arranged offset in a direction perpendicular to the direction of air flow to the air flow (5),

is arranged in particular receding under a surface (15) of the device, which is overflowed by the air flow (5) parallel to the surface (15).

10. Device according to one of the preceding claims, characterized

characterized in that the emitter assembly (3) is traversed by air and with the emitter assembly (3) components, in particular atoms and / or molecules of the air of the air stream (5) are timed ionizable, in particular the emitter arrangement (3) can be driven by air

Includes electrodes.

11.Vorrichtung according to any one of the preceding claims, characterized

characterized in that the at least one detector arrangement (7) a. at least one coil element (7b) through which the emitted particles (4) can be passed with the air flow (5), in particular wherein the at least one coil element (7b) surrounds a tube (7a) through which air flows and / or b. at least one electrically conductive baffle (7c) comprises and / or c. at least one mass spectrometer (7c) and / or d. at least one pair of electrodes (7c) comprises an electric field formed between them, with which charged particles are attracted from the air stream and / or e. a plurality of distributed in space particle detectors comprises, in particular a plurality of particle detectors, which are annular, preferably with the same angular distance, preferably inside and / or outside along the circumference of an air-flowed pipe or air-flowed pin are arranged.

12. Device according to one of the preceding claims, characterized

characterized in that it comprises a support element (9) on which the

Emitter arrangement (3) and the at least one detector arrangement (7) are arranged one behind the other in a common rectilinear extent, wherein the carrier element (9) at least one tail unit (13), in particular formed as a from the support member (9) upstanding fin (13) is and the carrier element (9) on a base member (12) is rotatably articulated, in particular the articulation point (10) in

Air flow direction in front of the emitter assembly (3) is arranged.

13. The apparatus according to claim 11, characterized in that the

Basic element (12) Part of an aircraft or ground-based

Vehicle or a gondola or a wing of a wind turbine.

14. The apparatus of claim 11 or 12, characterized in that the carrier element (9) with one of the articulation point (10) spaced area in an arcuate guide groove (11) is guided.

15. Device according to one of the preceding claims 11 to 13, characterized

in that the position of the carrier element (9) relative to the base element (12) is detected by sensors, in particular by at least one sensor in the guide groove (11) or on the carrier element (9) or in / at the articulation point (10).

16. Device according to one of the preceding claims, characterized

in that the emitter arrangement (3) and / or detector arrangement (7) can be heated, in particular as a function of the height of the signal of detected particles (4).

17. Device according to one of the preceding claims, characterized

in that the emitter arrangement is arranged at the tip region of a pin (17) which can be flowed against / flowed by the air flow, in particular whose longitudinal direction is at least substantially parallel to the air flow, wherein the at least one detector arrangement (7) is annularly spaced from the tip region (17a)

Circumferential direction of the pin (17) is arranged around the pin surface around.

18. The apparatus according to claim 17, characterized in that the

Tip region (17 a) is tapered, in particular wherein the

Emitter assembly (3) on / in the maximally tapered beginning of the tip portion (17 a) is arranged.

19. The apparatus of claim 17 or 18, characterized in that the at least one detector arrangement (7) in the circumferential direction into a plurality, in particular equiangularly spaced detectors (7a) is divided.

20. Device according to one of the preceding claims 17 to 19, characterized

characterized in that the pin (17) is hollow and the

Emitter assembly (3) in the tip region (17a), in particular in / on the tapered tip portion (17a) around an air flow flowed through opening (17b) of the hollow pin (17) is arranged around, preferably wherein the hollow Pin (17) in its interior comprises a dynamic pressure sensor (18) or the hollow pin is part of a Pitot tube.

21. Aircraft, in particular aircraft or helicopter comprising

at least one device according to one of the preceding claims, in particular comprising pairs of two devices according to one of the preceding claims, which are opposite to the wings above and below.

22. A method of measuring air velocity relative to an object,

in particular a vehicle, preferably an aircraft, more preferably an aircraft, characterized in that by means of an emitter assembly (3) time-controlled, in particular temporally pulsed particles (4) are emitted, preferably charged subatomic, atomic or molecular particles, with the flowing air ( 5) are moved from the emitter assembly (3) towards at least one detector assembly (7) spaced from the emitter assembly (3), and the time is detected by the at least one detector assembly (7) to cause the particles (4) to travel a known length (x) require a measuring path, in particular between the emitter array (3) and a

Detector assembly (7) and / or between two detector assemblies (7, 7b) or two spaced detection elements (7b) of a detector array is formed.

23. A method for monitoring the flow on the wings of an aircraft, characterized in that by means of a device according to any one of the preceding claims, the air velocity above and below at least one wing of the aircraft is measured and when exceeding a predetermined speed difference, a warning is signaled or be made automatic intervention in the control of the aircraft, in particular, causes the measured

Speed difference is reduced.