JP5237192B2 - Scatter collection device for wind tunnel - Google Patents

Description

  The present invention relates to a wind tunnel scattered matter collecting apparatus mainly used in a flutter test.

  In a wind tunnel test conducted for aircraft development, etc., a flutter test for confirming a wing flutter (aeroelastic vibration) phenomenon is essential. In such a flutter test, in order to verify the airflow conditions and blade conditions in which the flutter phenomenon occurs, it is necessary to repeat the test many times by actually causing the flutter in the model and examining the conditions in which the flutter phenomenon occurs. For this reason, it is common to provide an emergency stop device in the transonic wind tunnel to prevent damage to the model due to the occurrence of flutter (see, for example, Patent Document 1 and Non-Patent Document 1).

  However, when the flutter phenomenon actually occurs, the vibration suddenly diverges, and as a result, the model is destroyed and scattered in the air passage of the wind tunnel, which may damage the wind tunnel. When flutter testing is performed in a continuous flow type wind tunnel with a circular air passage, such scattered matter may be sucked into the air blower, causing serious damage such as damage to the air moving blades of the air blower and impossibility of air blowing. .

  Therefore, the present situation is that the flutter test is performed in an intermittent blowing type wind tunnel in which the influence of scattered objects is relatively small. Further, only in the case of the model M ′ having only the wings, the model M ′ is injected into the air flow S ′ in the measurement section at a high speed as in the intermittent blowing type wind tunnel 101 shown in FIG. When the phenomenon occurs, there is a case in which a model ejection device 103 is used that retracts outside the air flow S ′ of the wind tunnel 101 at a high speed before the model M ′ is destroyed.

JP 2004-109067 A

Aerospace Technology Research Institute TR-1197 “Transient Wind Tunnel Flutter Emergency Stop Device Preliminary Test (Part 1) Flutter Stop Plate Basic Performance Test” April 1993

  However, the intermittent blowing type wind tunnel as described above has a problem that the test efficiency is low and it is difficult to determine the retreat timing even if a model injection device is used.

  Therefore, flutter phenomenon occurs suddenly in continuous circulation type wind tunnel as well as intermittent blowing type wind tunnel, and vibrations are suddenly diverged, and even if the model is destroyed and scattered in the air channel of the wind tunnel, the scattered matter is recovered. There is a demand to be able to do that.

  In addition to the flutter test, there are many tests that may cause scattered objects, such as tests involving scattering of small parts and various dumping / dropping tests. There is a demand to be able to collect the scattered matter scattered in the air passage.

  It is an object of the present invention to provide a wind tunnel flying object collecting apparatus capable of collecting flying objects in various wind tunnel tests in which flying objects may occur.

  The invention of claim 1 is a wind tunnel scattered matter recovery device used in a wind tunnel in which a strut that supports a model is arranged in an air passage through which an air flow of a predetermined wind speed flows, and in a fixed portion of the constant strut, A scattered matter collecting member for collecting scattered matter from the model is provided, and this scattered matter collecting member is in an open position for blocking the air passage during the collecting operation, and is incorporated in the fixed portion of the strut during the non-collecting operation. It is a closed position along the surface of the fixed portion. Here, the airflow flowing through the air passage includes not only the case where the airflow is supplied by a blower but also the case where the airflow is supplied from an air storage tank.

  In this way, during the non-recovery operation, the scattered matter collecting member is incorporated in the fixed portion of the strut or is installed along the surface of the fixed portion of the strut. Thus, the flutter test and other various wind tunnel tests can be performed without any change. In other words, during the wind tunnel test, a scattered matter recovery member is installed so that it does not become a resistance of the airflow flowing through the air passage of the wind tunnel, and if the scattered matter is generated from the model during the test, the scattered matter is scattered. To avoid being collected and diffused. Therefore, damage to the wind tunnel is also prevented.

  According to a second aspect of the present invention, the scattered matter collecting member can be configured to have airflow permeability and to be opened and closed at a fixed portion of the strut.

  In this way, at the time of the collecting operation for collecting the scattered matter, the scattered matter collecting member becomes an open position and shuts off the air passage, but the scattered matter collecting member has air permeability, so the scattered matter collecting member There is no great air resistance, and there is almost no risk of the scattered matter collecting member being damaged by the dynamic pressure of the airflow.

  Preferably, the scattered matter collecting member is attached to the fixed strut so as to be rotatable about a rotation axis in the height direction of the fixed strut with the downstream end as a fulcrum. .

  If it does in this way, the opening operation of the scattered matter collection member will be assisted by the air current flowing through the air passage, and the opening operation will be possible without requiring large power. Therefore, during the recovery operation, if the upstream portion of the scattered matter collecting member is pushed out into the air passage, the scattered matter collecting member is rotated by the airflow flowing through the air passage, and the air passage is blocked for collecting the scattered matter.

  A bypass air passage that connects a downstream position of the fixed portion of the strut and an upstream position of the blower, and an opening / closing means provided in the middle of the bypass air passage. It is desirable that the opening / closing means is opened by detecting the occurrence of scattered objects from the model.

  In this way, the scattered matter from the model is detected, the scattered matter collecting member is in the open position, and the bypass air passage is opened while being in the collecting state. The resistance fluctuation, that is, the load fluctuation of the blower is alleviated.

  According to a fifth aspect of the present invention, the wind tunnel can be a continuous circulation type wind tunnel having an annular air passage and generating an air flow by a blower.

  In this way, it is possible to avoid the occurrence of enormous damages such as the scattered matter being sucked into the blower and damaging the blower moving stationary blade to disable the blower. Various types of wind tunnel tests that may generate scattered matters such as flutter tests can be safely performed while avoiding damage to the blower or the like, even in a continuous circulation type wind tunnel with high test efficiency.

  In the present invention, as described above, the scattered matter collecting member for collecting the scattered matter from the model is built in the fixed strut or installed along the surface of the fixed strut, and the scattered matter collecting member is not recovered. Since it does not become resistance of the airflow in a ventilation path sometimes, a scattered matter collection member can be installed, without setting it as the resistance of the airflow which flows through a ventilation path.

It is explanatory drawing which shows embodiment which provided the scattered matter collection | recovery apparatus in the continuous circulation type wind tunnel which is one embodiment of this invention. It is a detailed view near the strut. It is explanatory drawing which shows embodiment which provided the scattered material collection | recovery apparatus in the intermittent blowing type wind tunnel. It is explanatory drawing of the conventional wind tunnel apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, a continuous circulation type wind tunnel 1 according to an embodiment of the present invention is configured such that an air flow having a predetermined wind speed is generated by a blower 2, and the generated air flow 3 continues in an annular shape. In the middle, the reduction portion 3A in which the width of the air passage 3 is gradually narrowed, the measuring portion 3B in which the width of the air passage is the narrowest, and the width of the air passage 3 are gradually increased. A diffusing portion 3C that is widened is arranged. A model M to be subjected to a wind tunnel test is arranged in the measurement unit 3B, and an airflow having a predetermined wind speed is blown against the model M. Corner vanes 6 that change the direction of the airflow in the air passage 3 are provided at each corner portion in the middle of the air passage 3. In this embodiment, the ceiling surface and floor surface of the wind tunnel 1 are flat surfaces, but the present invention is not limited to such a wind tunnel.

  As shown in FIG. 2, a strut 8 that supports a model support device 7 that supports the model M is disposed in the measurement unit 3B. The strut 8 includes a movable strut 8A that is positioned upstream and supports the model support device 7 so as to be movable in the vertical direction, and a fixed strut 8B that supports the movable strut 8A so as to be movable in the vertical direction. The model support device 7 is moved up and down by the vertical movement of the movable strut 8A, and the position / posture of the model M can be set according to the test conditions by using it together with the angle changing operation of the model support device 7.

  On both side surfaces of the fixed strut 8B, plate-like scattered matter collecting members 11 are rotatably provided with the downstream end as a rotation fulcrum P. That is, it is attached to the fixed strut 8B so as to be rotatable around the rotation axis in the height direction of the fixed strut 8B. The scattered matter collecting member 11 is made of a material such as a perforated plate, a wire mesh, or a net, and has air permeability that does not cause a large resistance to the air current flowing through the air passage 3. Moreover, the scattered matter collection | recovery member 11 has the intensity | strength which fastens a scattered matter.

  If the upstream part of the scattered matter collecting member 11 is pushed into the air passage 3 by the piston rod 13 of the cylinder, which is an actuator provided in the fixed strut 8B, it opens until it hits the stopper 12 due to the dynamic pressure of the airflow. It has become. In this way, the state of the scattered matter collecting member 11 is changed from the closed position to the open position by the actuator (piston rod 13 of the cylinder) and the stopper 12. In addition, as a method of pushing out the scattered matter collecting member 11 into the air blowing path 3, a method of ejecting high pressure air by jetting, a method of pushing out by a spring force, a method of pushing out by the repulsive force of the electromagnet of the same polarity, a rotating shaft with a motor A rotating method can also be used.

  That is, it becomes an open position that blocks the air passage 3 during the recovery operation (see the one-dot chain line in FIG. 1), and is built in the concave portion of the fixed strut 8B during the non-recovery operation. It becomes the closed position which becomes flush with. In the closed position, the scattered matter collecting member 11 only needs to be able to reduce the air resistance by the scattered matter collecting member 11 so that various wind tunnel tests can be performed in the same manner as a normal wind tunnel. A state along the outer surface of the strut 8B can also be adopted.

  Since the scattered matter collecting member 11 is opened so as to block the air passage 3 and is in contact with the stopper 12, the scattered matter collecting member 11 blocks the air passage 3 in cooperation with the stopper 12. It is avoided that the flying object flies downstream from the flying object collecting member 11.

  Since the scattered matter collecting member 11 has a structure in which the upstream side portion is opened with the downstream end as a fulcrum, if the scattered matter collecting member 11 is opened so as to block the air passage 3, the air flow pressure of the air passage 3 Therefore, the driving force can be saved. In addition, the drive mechanism can be reduced in size and simplified. Thereby, it is easy to set it as the structure closed in the ventilation path 3, and an application range can be extended also to wind tunnels which require airtightness, such as a pressurization type wind tunnel and a low temperature wind tunnel.

  The scattered matter collecting member 11 is installed in the downstream fixed portion (fixed strut 8B) of the strut 8 that has been conventionally used for supporting the model M in the wind tunnel 1 or is installed along the surface at a normal time ( In the closed position (at the time of non-recovery operation), the pressure loss in the air passage 3 of the wind tunnel 1 can be maintained substantially the same as when the scattered matter recovery member 11 is not provided.

  In addition, since the scattered matter recovery member 11 is installed in the measurement unit 3B having a small cross-sectional area of the air passage 3, the recovery cross-sectional area becomes smaller than that in the diffusion unit 3C on the downstream side of the fixed strut 8B. This is advantageous in realizing reliable collection. Further, the scattered matter collecting member 11 can be small in size, and the manufacturing cost can be reduced.

  Since the scattered matter collecting member 11 has airflow permeability, even if the scattered matter collecting member 11 is in an open position where the air blowing path 3 is shut off, it does not become a large air resistance. The sudden change in the load of the blower 2 is alleviated by the air permeability of the scattered matter collecting member 11. The stopper 12 can also have air permeability.

  In addition, since the scattered matter collecting member 11 has a strength for retaining the scattered matter, the scattered matter from the model M does not flow into the diffusion portion 3C, and the scattered matter collecting member 11 has air permeability and is scattered. Therefore, the scattered matter from the model M can be stably held at the collection position by the gas flow pressure.

  The downstream position of the fixed strut 8B and the upstream position of the blower 2 are connected by a bypass air passage 21, and an on-off valve 22 is provided in the bypass passage 21, thereby providing further load fluctuation mitigation measures. Then, the opening / closing valve 22 is opened simultaneously with the detection of the scattered matter from the model M or the opening of the scattered matter collecting member 11, and the bypass air passage 21 is opened, so that the burden on the blower 2 is reduced.

  If comprised as mentioned above, in order to suppress air resistance to the minimum at the time of normal time (at the time of a wind tunnel test), the scattered matter collection | recovery member 11 will be in the closed position which becomes substantially parallel to the airflow which flows in the ventilation path 3. ing. At this time, the scattered matter collecting member 11 is substantially flush with the surface of the fixed strut 8B.

  On the other hand, when abnormal vibration occurs in the model M and it is determined that the flutter phenomenon occurs, and the scattered matter from the model M is actually generated, the upstream portion of the scattered matter collecting member 11 becomes an actuator (for example, the piston rod 13 of the cylinder). When it is pushed and protrudes into the air passage 3, the scattered matter collecting member 11 instantaneously rotates with the downstream end as a rotation fulcrum P due to the dynamic pressure of the air flow in the air passage 3, hits the stopper 12, and blows the air passage 3. It becomes an open position which interrupts | blocks with the stopper 12. FIG. Thereby, the flying object collection member 11 collects the flying object in the model M sky.

  By the way, the timing of opening the scattered matter collecting member 11 is the moment when the flutter phenomenon is detected and the scattered matter from the model M is detected by visual observation (observation) of the operator after the occurrence of the flutter phenomenon, as will be enumerated below. It is. The flutter phenomenon is determined to occur when (i) the operator observes the state of the model M and abnormal vibration occurs in the model (ii) a strain gauge is attached to the model (for example, wing) If the amount vibrates abnormally, or if an accelerometer is attached in the same way and abnormal vibration occurs (see Non-Patent Document 1 mentioned above), (iii) if the signal of the built-in model balance vibrates abnormally, (iv) When the model vibration is recognized and abnormal vibration occurs (when the method (i) described above is automatically determined by the image recognition device), the flutter phenomenon alerts the operator, and then the operator The presence or absence of scattered matter from the model M is detected by visual observation (observation).

  In addition to the visual observation (observation) by the above-mentioned operator, as shown in the following (v) to (vii), the scattered matter from the model M after the flutter phenomenon is directly detected by a sensor or the like, and the scattered matter is detected. It is also possible to operate the actuator in conjunction with detection of the occurrence and open the on-off valve 22.

  (v) Detect scattered objects from the model M by image recognition. For example, if the model is colored and photographed with a different color from the measurement part of the wind tunnel, and a part of the model is found behind the model position, the scattered object Detects the occurrence of

  (vi) An optical sensor is embedded in the wall of the model, and when the scattered object is detected by the optical sensor, the occurrence of the scattered object is detected.

  (vii) As a model for flutter testing, when using a model in which each part is connected with a wire in a flexible structure so that flutter is more likely to occur, a weak current is passed through the wire originally inside, and the wire is disconnected. Electrically detected, and disconnection is detected as the occurrence of scattered objects.

  In addition to the above, the present invention can be implemented with the following modifications.

  (1) The present scattered matter collecting apparatus is not limited to a continuous circulation type wind tunnel, but can be applied to an intermittent blowing type wind tunnel 101 'as shown in FIG. In this case, the scattered matter collecting member 11 is provided in the fixed strut 104B on the downstream side of the movable strut 104A among the struts 104 for supporting the model M so as to be built in or along the surface. The stopper 12 may be provided.

  (2) The stopper 12 is not necessarily provided. For example, the stopper 12 may be configured such that the scattering recovery member 11 rotates by a certain angle on the actuator side and the air passage 3 is blocked while rotating by this certain angle. It is also possible to omit 12.

  (3) The present invention is mainly used for flutter tests, but in addition to flutter tests, it should be used for tests involving the scattering of small parts, and various tests that may cause scattered matter such as various dumping / dropping tests. Can do. For example, even if it is a drop test that needs to measure the thrown object flowing in the airflow, it can be used for the drop test as long as it is measured only for a short period after the drop.

M Model 1 Continuously recirculating wind tunnel 2 Blower 3 Air passage 4 Measurement unit 6 Corner vane 7 Model support device 8 Strut 8A Movable strut 8B Fixed strut (Strut fixed portion)
11 Scattered material recovery member 21 Bypass air passage 22 On-off valve (open / close means)

Claims (5)

A wind tunnel scattered matter collecting device used in a wind tunnel in which a strut supporting a model is arranged in a ventilation path through which an air flow of a predetermined wind speed flows,
The fixed part of the strut is provided with a scattered matter collecting member for collecting the scattered matter from the model,
The scattered matter collecting member is in an open position that blocks the air passage during a collecting operation, and is a built-in portion of the fixed portion of the strut or a closed position along the surface of the fixed portion during a non-collecting operation. Scatter collection device.
2. The scattered matter collecting apparatus for a wind tunnel according to claim 1, wherein the scattered matter collecting member has airflow permeability and is openable and closable at a fixed portion of the strut.
3. The front scattered matter collecting member is attached to the fixed strut so as to be rotatable about a rotation axis in a height direction of the fixed strut with a downstream end portion as a fulcrum. Wind tunnel scattered matter collection device.
A bypass air passage connecting a downstream position of the fixed portion of the strut and an upstream position of the blower;
Opening and closing means provided in the middle of the bypass air passage,
The scattered matter collecting apparatus for a wind tunnel according to any one of claims 1 to 3, wherein the occurrence of scattered matter from the model is detected to open the opening / closing means.   5. The wind tunnel scattered matter collecting apparatus according to claim 1, wherein the wind tunnel is a continuous circulation type wind tunnel in which an air passage is annular and an air flow is generated by a blower.

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