JPH03272430A - High enthalpy supersonic wind tunnel apparatus and operation thereof - Google Patents

Abstract

PURPOSE:To lower a minimum starting pressure of a supersonic wind tunnel by providing a means to change distance between open ends of opposed supersonic nozzles and an open end of a supersonic diffuser. CONSTITUTION:A high enthalpy gas stored at a high pressure gas supply source is introduced to a supersonic nozzle 5 to be jetted into a measuring chamber 6. By raising a pressure of the high pressure gas supply source, a supersonic diffuser 10 is made ready to start. After the starting of the diffuser 10, a diffuser moving section 22 is moved downstream in an air current make a free jet space between the downstream side of the nozzle 5 and the upstream side of a contraction passage 7. As a result, a free jet section is kept supersonic free from the movement of the moving section 22. With such an arrangement, in the starting of the diffuser 10, a free jet area can be reduced remarkably between the nozzle 5 and the diffuser 10 thereby enabling the lowering a starting pressure of the diffuser 10 with a reduction in a pressure loss as caused when the gas is jetted freely.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a supersonic wind tunnel, and particularly to a high enthalpy supersonic wind tunnel apparatus and operating method suitable for reducing starting pressure.

[Conventional technology]

Conventionally, information on free jet supersonic wind tunnels has been published in Journal of the Aeronautical Sciences, June issue (
1952) pages 375 to 384 (JOURNA
L OF THE AERONAUTICAL 5CI
ENCES, JUN (1952) PP375-38
4) and others. The configuration of a conventional free jet supersonic wind tunnel is shown in FIG. A supersonic nozzle 5 connected to a high-pressure gas supply source and having a tapered and divergent shape is installed such that its nozzle outlet end is located at an arbitrary spatial position in the measurement chamber 6. At the other end of the measurement chamber 6, a supersonic diffuser 10 consisting of a contracting channel, a constant cross-sectional area channel, and an expanding channel from the upstream side.
is connected. Further, each device is fixed except for the upper and lower walls of the constant cross-sectional area flow path (throat portion of the supersonic diffuser) 8, which is the smallest cross-sectional area portion of the supersonic diffuser 10. Shock waves generated by supplying high pressure gas. The flow of water downstream from the supersonic diffuser throat and the state in which the measuring section reaches a specified supersonic speed is called the starting state of the supersonic diffuser. Here, starting the supersonic wind tunnel will be explained using FIG. 14. The vertical axis of the figure represents the total pressure PO of the high-pressure gas supply source, and the horizontal axis represents the position of the generated shock wave within the flow path. When the total pressure Pa of the high-pressure gas supply source is gradually increased, a flow is generated in the wind tunnel, and at a certain value of Pa, the flow reaches the speed of sound (chokes) at the nozzle throat 4, and a shock wave is generated (point a in Figure 14). . This shock wave moves downstream as Po increases. If the PO is further increased when the shock wave has reached the inlet of the reduced channel 7 of the supersonic diffuser (point in Figure 14), a shock wave swallowing phenomenon occurs, and the shock wave reaches the supersonic speed downstream of the diffuser throat 8. The measurement chamber 6 moves to a position having the same cross-sectional area as the reduced flow path 7 of the diffuser (point C in FIG. 14), and the measuring chamber 6 becomes a --like supersonic flow, and enters the starting state. The minimum pressure Pos required for starting is called the minimum starting pressure. When Po>Pos (points C to d in FIG. 14), the shock wave is downstream from the diffuser throat 8, and in this state, the measurement chamber 6 is in a supersonic state of a prescribed Matsusha number. When Pa is gradually decreased from this state, the shock wave retreats to the diffuser throat 8 (point e in Figure 14). Furthermore, when Po is decreased, the shock wave retreats upstream from the diffuser throat 8 to a point rl (point f in FIG. 14) having the same cross-sectional area as the diffuser throat 8, and the shock wave returns to the upstream side of the supersonic diffuser again. Therefore, the negative supersonic flow in the measurement chamber 6 is eliminated. Total pressure P just before this
ob is the minimum total pressure required to achieve a supersonic flow in the measurement chamber 6 and operate steadily, and is referred to as the minimum operating pressure. Figure 15 shows the distance X between the supersonic nozzle outlet and the supersonic diffuser inlet and the minimum starting pressure P of the supersonic diffuser.
This shows the relationship with OS. From the figure, it can be seen that the shorter the distance X between the supersonic nozzle outlet and the supersonic diffuser inlet, the easier it is to start. This means that between the supersonic nozzle exit and the supersonic diffuser entrance,
This is because there is pressure loss in the jet portion, and the longer the jet distance, the greater the pressure loss. As a method of lowering the minimum starting pressure,
As described in Publication No. 9432, the nozzle throat and diffuser throat are set in advance so that the throat cross-sectional area is set to a low Matsuha number M□ that is less than or equal to the set Matsuha number M. After the number reaches M, the diffuser throat is changed to an aperture with a wind speed of the Matsuha number M by a jack or the like, and then the nozzle throat is changed to an aperture of the Matsuha number M.
The inside of the measuring cylinder is brought into a flow state with a specified Matsusha number M.

[Problem to be solved by the invention]

The above conventional technology can be applied to wind tunnels in which a supersonic nozzle, a measurement chamber, and a supersonic diffuser form a series of continuous ducts; In this case, since the pressure loss in the jet portion is large, even if the above-mentioned conventional technology is applied, the minimum starting pressure cannot be reduced. Furthermore, in a high-enthalpy wind tunnel where the supplied gas is at a high temperature, it is necessary to install a cooling device on the walls of the supersonic nozzle and the supersonic diffuser to cool the base material of the supersonic nozzle and the supersonic diffuser. In that case, the method of narrowing the flow path of the supersonic nozzle and the supersonic diffuser has the problem that the shape of the cooling pipe must change as the wall shape changes, so the above-mentioned conventional technology cannot be applied. An object of the present invention is to provide a device and method of operating the same for reducing the minimum starting pressure of a supersonic wind tunnel that supplies high enthalpy gas.

[Means to solve the problem]

The above purpose is to provide a gas supply source that supplies high enthalpy gas, a gas supply pipe connected to the gas supply source on one side, and one end connected to the gas supply pipe and having a constriction inside and the other side having an open end. a supersonic nozzle from which the high enthalpy gas expands and ejects; a supersonic diffuser having one opening end facing the opening end of the supersonic nozzle and comprising a contracting channel, a constant cross-sectional area channel, and an expanding channel; , a measurement chamber comprising a shield that shields the supersonic nozzle and the supersonic diffuser from outside air;
In a high enthalpy supersonic wind tunnel apparatus having an exhaust pipe connected to an enlarged flow path of the supersonic diffuser, a means is provided for changing a distance between an opening end of the supersonic nozzle and an opening end of the supersonic diffuser that face each other. This is achieved by The above object is such that the means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser causes the opening end of the supersonic nozzle and the opening end of the supersonic diffuser to face each other and approach or separate from each other. It is achieved by being a means. The above object is characterized in that the means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser includes means for moving a reduction channel of the supersonic diffuser provided in the measurement chamber; This is achieved by having a slidable double pipe provided in a constant cross-sectional area flow path connected to the flow path. The above object is characterized in that the means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser includes a means for moving the supersonic nozzle provided in the measurement chamber and a means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser. This is achieved by having a slidable double pipe provided in the gas supply pipe. The above object is characterized in that the means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser moves a constant cross-sectional area flow path of the supersonic diffuser;
This is achieved by having a sliding part provided between the constant cross-sectional area flow path of the supersonic diffuser and the measurement chamber wall, and a bellows provided between the enlarged flow path of the supersonic diffuser and the exhaust pipe. Ru. The above object is characterized in that means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser is provided between means for moving the supersonic nozzle and the supersonic nozzle and a wall of the measurement chamber. This is achieved by having a sliding portion and a bellows provided between the supersonic nozzle and the gas supply pipe. The above object is achieved by providing, in place of the bellows, a double-structured sliding section that connects a straight pipe section to the downstream side of the enlarged channel of the supersonic diffuser and the exhaust pipe. The above object is achieved by providing, in place of the bellows, a sliding part with a double structure, which connects a straight pipe part to the gas supply pipe on the upstream side of the contracting flow path of the supersonic nozzle. In the above object, the means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser includes the measurement chamber wall fixed to the supersonic nozzle and the measurement chamber wall fixed to the supersonic diffuser. A sliding part provided between the
This is achieved by having means for moving the measurement chamber on the side of the supersonic diffuser, and a bellows provided between the expanded flow path of the supersonic diffuser and the exhaust pipe. In the above object, the means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser includes the measurement chamber wall fixed to the supersonic nozzle and the measurement chamber wall fixed to the supersonic diffuser. A sliding part provided between the
This is achieved by including means for moving the measurement chamber on the supersonic nozzle side, and a bellows provided between the supersonic nozzle and the gas supply pipe. The above object is achieved by providing a bellows in place of the sliding part. The above object is achieved by providing, in place of the bellows, a double-structured sliding section that connects a straight pipe section to the downstream side of the enlarged channel of the supersonic diffuser and the exhaust pipe. The above object is achieved by providing, in place of the bellows, a sliding part with a double structure, which connects a straight pipe part to the gas supply pipe on the upstream side of the contracting flow path of the supersonic nozzle. The above object is such that means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser is slidably connected to a duct-shaped measurement chamber connected downstream of the supersonic nozzle. This is achieved by including an inserted movable diffuser, a means for moving the movable diffuser, and a sealing member provided on the inside of the duct-shaped measurement chamber. The above object is such that the means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser is configured such that one side is slidably inserted into the gas supply pipe and the other side is slidably inserted into the duct-shaped measurement chamber. This is achieved by having a movable nozzle that can be freely inserted, a means for moving the movable nozzle, the gas supply pipe that slides on the movable nozzle, and a sealing member provided on the inside of the measurement chamber. The above object is such that the means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser is a shielding tube into which the supersonic nozzle and the supersonic diffuser are slidably inserted facing each other. and means for moving the shielding tube in the insertion direction of the supersonic nozzle or the supersonic diffuser. The above object is such that the means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser has a reduced flow path made of a plurality of members of the supersonic diffuser and one constant cross-sectional area flow path. This is achieved by having a rotatably connected member and a means for rotating the plurality of members. The above object is characterized in that the means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser includes a plurality of pressure sensors provided in the supersonic diffuser or a measurement chamber, and a plurality of pressure sensors that output input the static pressure distribution of the supersonic diffuser or the measurement chamber and compare it with a predetermined static pressure distribution at the time of startup, and if it is determined that the supersonic nozzle or the measurement base or the supersonic diffuser has started, It is distantly related by having a control means for moving it. The above purpose was to expand a high enthalpy gas using a supersonic nozzle, eject it into a measurement chamber at supersonic speed, and conduct a specified wind tunnel experiment.
In the method of operating a high-enthalpy supersonic wind tunnel, the pressure of the gas ejected into the measurement chamber is increased by a supersonic diffuser and guided to the exhaust system, wherein the high-enthalpy gas is supplied to the supersonic nozzle so that the supersonic flow reaches the supersonic speed. This is further improved by providing a method for operating a high-enthalpy supersonic wind tunnel that changes the distance between the open end of the supersonic nozzle and the open end of the supersonic diffuser as the supersonic nozzle passes through the diffuser. The above object is distantly related by providing a method for operating a high-enthalpy supersonic wind tunnel in which the passage of the supersonic flow is determined based on the static pressure distribution output from the supersonic diffuser or a plurality of pressure sensors provided in the measurement chamber. Ru.

[Effect]

By reducing the distance between the exit end of the supersonic nozzle and the inlet of the supersonic diffuser prior to startup, the boundaries of the free jet of gas blown out from the supersonic nozzle are reduced, and the pressure loss due to jetting is reduced, which reduces the starting pressure. It can be lowered. After the high-enthalpy supersonic wind tunnel is started, the exit end of the supersonic nozzle and the inlet of the supersonic diffuser are separated to create a free jet space in the measurement chamber and wind tunnel tests at supersonic speeds can be performed. If the exit end of the supersonic nozzle and the inlet of the supersonic diffuser are separated, a pressure loss will occur due to the ejection, but once the starting shock wave is pushed downstream of the diffuser throat due to the difference between the starting pressure and the operating pressure, the pressure loss due to the ejection will be reduced. Even if there is, as long as the pressure loss is within the range of the difference between the starting pressure and the operating pressure, the measurement chamber can maintain the predetermined Matsuha number.

[Example 1] Hereinafter, a first example of the present invention will be explained with reference to FIG. 9.
The basic configuration of the supersonic wind tunnel of the present invention includes a high-pressure gas supply source (not shown) that supplies high-enthalpy gas, a high-pressure gas supply pipe 2 that guides the high-enthalpy gas from the high-pressure gas supply source to the supersonic nozzle 5, and a downstream thereof. A supersonic nozzle 5 with a tapered and divergent shape that expands high enthalpy gas to a supersonic state, which is placed on the side, and a measurement chamber in which the expanded gas is ejected through the supersonic nozzle 5 and the ejected gas is shielded from the atmosphere. 6, a supersonic diffuser 10 consisting of a reduced flow path 7, constant cross-sectional area flow paths 8, 60, and an enlarged flow path 9, which raises the gas ejected into the measurement chamber 6 to exhaust pressure and guides it to the exhaust system; It consists of an exhaust pipe 11 provided for exhausting the gas flowing out through 10 to the exhaust system, and an exhaust system. Further, 4 is the minimum cross-sectional area (throat) of the supersonic nozzle. In FIG. 1, a supersonic diffuser 10 has a sliding portion in a constant cross-sectional area flow path, and has a structure as shown below. The supersonic diffuser 10 is composed of a diffuser moving section 22 consisting of a contracting channel 7 and an inner constant cross-sectional area channel 60, and a diffuser fixing section 23 consisting of an outer constant cross-sectional area channel 8 and an expanding channel 9. The diffuser moving part 22 has a structure in which it is inserted inside the diffuser fixing part 23 and slides, or a structure in which the diffuser fixing part 23 is inserted inside the diffuser moving part 22 and the diffuser moving part 22 slides. 22 is supported by a sliding bearing 17 and has a structure that allows it to move only back and forth in the gas flow direction. Further, the diffuser moving section 22 has a structure that allows it to be moved forward and backward in the direction of airflow by a jack 15 that uses oil pressure, compressed air, and the like. The jack 15 has one end of a part of the cylinder fixed to the inner wall of the measurement chamber 6, and the tip of the moving part is connected to the jack supporting member 16 of the diffuser moving part 22. Therefore, by operating the jack 15 attached to the inner wall of the measurement chamber 6, the diffuser moving section 22 can be moved in the front-rear direction. Furthermore, the inner cross-sectional area constant flow path 60 of the diffuser moving part 22 and the outer cross-sectional area constant flow path 8 of the diffuser fixed part 23
Since the sliding portion is sealed by the sealing member 13, the gas inside the supersonic diffuser 10 will not leak into the measurement chamber 6 due to movement of the diffuser moving portion 22. First, before supplying high enthalpy gas from the high pressure gas supply source to the supersonic nozzle 5, the jack 15 is actuated to move to the vicinity where the tip of the reduction flow path 7 touches the outlet of the supersonic nozzle 5, and then stopped. . next. The high enthalpy gas stored in the high pressure gas supply source is guided to the supersonic nozzle 5 and ejected from the supersonic nozzle 5 into the measurement chamber 6. Shock waves are generated in the measurement chamber 6, but by increasing the pressure of the high-pressure gas supply source, they pass through the constant cross-sectional area flow path of the supersonic diffuser 10 at a certain pressure and move downstream, is in the starting state. After the supersonic diffuser 10 is started, the jack 15 is operated in the direction in which the moving part of the jack 15 is contracted to move the diffuser moving part 22 in the downstream direction of the airflow, and the supersonic nozzle 5
A free jet space is provided between the downstream side of the contraction channel 7 and the upstream side of the contraction channel 7. In this way, even if the diffuser moving section 22 moves as described above, the free jet section maintains the supersonic state. When the supply flow rate is large and the fluid pressure is high, the gas ejected from the supersonic nozzle hits the contracting flow path 7 of the supersonic diffuser, creating a force that moves the supersonic diffuser in the downstream direction of the airflow, causing the sliding part to By creating a structure that moves smoothly, the supersonic diffuser can be moved without any parking force such as jerking. First, the supersonic diffuser is moved to the vicinity where the tip of the contraction channel 7 contacts the outlet of the supersonic nozzle 5, and is fixed by a stopper. Next, the high enthalpy gas stored in the high pressure gas supply source is guided to the supersonic nozzle 5 and ejected from the supersonic nozzle 5 into the measurement chamber 6 . After the supersonic diffuser starts, by removing the stopper, the supersonic diffuser moves in the downstream direction of the airflow due to the fluid force of the gas ejected from the supersonic nozzle. The contraction flow path 7 of the diffuser moving part 22 comes into contact with the end face of the diffuser fixing part 23, so that the movement of the diffuser moving part 22 downstream in the air flow direction is stopped. According to this embodiment, when starting the supersonic diffuser,
Since the free jet area between the supersonic nozzle and the supersonic diffuser can be significantly reduced, the pressure loss that occurs when the gas flows freely can be reduced, and the starting pressure of the supersonic diffuser can be lowered. Further, since the moving portion of the supersonic diffuser is only on the upstream side of the throat portion of the supersonic diffuser, there is an effect that the yoke force required to move the supersonic diffuser is small. Since the sliding part is located inside the measurement chamber, the pressure difference is smaller compared to a structure in which the sliding part is outside the measurement chamber, making it easier to seal the sealing part. There is. In the above embodiment, the supersonic nozzle 5 was fixed and the supersonic diffuser 10 was moved back and forth in the direction of the airflow to reduce the pressure loss due to gas ejection from the supersonic nozzle of the free jet type supersonic wind tunnel. The same effect can be obtained even if the supersonic diffuser IO is fixed and the supersonic nozzle 5 on the upstream side of the measurement chamber 6 is moved back and forth in the air flow direction. Therefore, the nozzle throat 4 is provided with a constant cross-sectional area flow path, and this straight pipe part is inserted into the inside of the high-pressure gas supply pipe 2 and slid. The structure is such that the supersonic nozzle 5 slides as it is inserted into the airflow, and the supersonic nozzle 5 can move back and forth in the direction of the airflow. A similar effect can be obtained by using a dynamic structure. Next, a second embodiment of the present invention will be described with reference to FIG. The present embodiment has a structure in which the supersonic diffuser 10 can be moved back and forth in the direction of airflow by a jack 15 using hydraulic pressure, compressed air, or the like. The jack 15 has one end of the cylinder part connected to the measurement chamber 6.
It is fixed to the outer side wall, and the tip of the moving part is connected to the jack support member 16 of the supersonic diffuser 10. Further, the contact portion between the side wall of the measurement chamber 6 and the supersonic diffuser 10 has a sliding structure sealed by a sealing member 13, and the downstream side of the enlarged channel 9 of the supersonic diffuser 10 is
It is connected to the exhaust pipe 11 by a bellows 14. Furthermore, since the supersonic diffuser 10 is supported by a sliding bearing 17, it has a structure in which it can only move forward and backward in the direction of air flow. Therefore, by operating the jack 15 attached to the outer wall of the measurement chamber 6, the supersonic diffuser 10 can be moved back and forth. At this time, since the sliding parts of the measurement chamber 6 and the supersonic diffuser 10 are sealed by the sealing member 13, the gas outside the measurement chamber 6 will not leak into the measurement chamber 6 due to the movement of the supersonic diffuser 10. . First, before supplying high enthalpy gas from the high pressure gas supply source to the supersonic nozzle 5, the jack 15 is activated to move the supersonic diffuser 10 to a point where the tip of the contraction channel 7 contacts the outlet of the supersonic nozzle 5. Move and stop. Next, the high enthalpy gas stored in the high pressure gas supply source is guided to the supersonic nozzle 5. It is ejected from the supersonic nozzle 5 into the measurement chamber 6. Measurement room 6
Shock waves are generated within the air, but by increasing the pressure of the high-pressure gas supply source, at a certain pressure the shock waves pass through the constant cross-sectional area flow path 8 of the supersonic diffuser 10 and move downstream.
The supersonic diffuser 10 is in a starting state. After the supersonic diffuser 10 starts, the moving part of the jack 15 operates in the extending direction to move the supersonic diffuser 10 in the downstream direction of the airflow, and connects the downstream side of the supersonic nozzle 5 and the upstream side of the supersonic diffuser IO. A free jet space is provided in between. In this way, even if the supersonic diffuser 10 moves as described above, the free jet section maintains the supersonic state. According to this embodiment, when starting the supersonic diffuser,
Since the free jet space between the supersonic nozzle and the supersonic diffuser can be significantly reduced, the pressure loss that occurs when the gas flows freely can be reduced, which has the effect of lowering the starting pressure of the supersonic diffuser. In the above embodiment, the pressure loss due to gas ejection from the supersonic nozzle 5 of a free jet type supersonic wind tunnel is reduced by fixing the supersonic nozzle 5 and moving the supersonic diffuser 10 back and forth in the direction of the air flow. However, the same effect can be obtained by fixing the supersonic diffuser 10 and moving the supersonic nozzle 5 back and forth in the direction of the air flow. Therefore, the same effect can be obtained by providing a bellows on the upstream side of the supersonic nozzle 5 and further providing a sliding structure in which the contact portion between the side wall of the measurement chamber 6 and the supersonic nozzle 5 is sealed with a sealing member. Next, a third embodiment of the present invention will be described with reference to FIG. 3. In this embodiment, the bellows 14 of the second embodiment shown in FIG. Either the straight pipe part 21 provided at
The supersonic diffuser 1 is inserted into the inside of the straight pipe section 21 provided downstream of the
It has a structure that allows 0 movement. Furthermore, during this movement, the space between the straight pipe section 21 and the exhaust pipe 11 is sealed by the sealing member 13, so that gas outside the exhaust pipe 11 does not enter into the inside of the exhaust pipe 11 due to the movement of the supersonic diffuser 10. do not have. First, before supplying high enthalpy gas from the high pressure gas supply source to the supersonic nozzle 5, the jack 15 is activated to move the supersonic diffuser 10 to a point where the tip of the contraction channel 7 contacts the outlet of the supersonic nozzle 5. Move and stop. Next, the high enthalpy gas stored in the high pressure gas supply source is guided to the supersonic nozzle 5 and ejected from the supersonic nozzle 5 into the measurement chamber 6 . A shock wave is generated in the measurement chamber 6, but by increasing the pressure of the high-pressure gas supply source, the shock wave passes through the constant cross-sectional area flow path 8 of the ultrasonic diffuser 10 and moves downstream at a certain pressure, causing the ultrasonic wave to move downstream. The sonic diffuser 10 is in the starting state. After supersonic diffuser 10 starts, Jack 1
The moving part 5 operates in the extending direction to move the supersonic diffuser 10 in the downstream direction of the airflow, and a free jet space is provided between the downstream side of the supersonic nozzle 5 and the upstream side of the supersonic diffuser 10. In this way, even if the supersonic diffuser 10 moves as described above, the free jet section maintains the supersonic state. According to this embodiment, since a bellows is not used on the downstream side of the supersonic diffuser, the moving distance can be increased, so there is an effect that the supersonic diffuser can be moved significantly back and forth in the flow direction of the airflow. In the above embodiment, the pressure loss due to gas ejection from the supersonic nozzle 5 of a free jet type supersonic wind tunnel is reduced by fixing the supersonic nozzle 5 and moving the supersonic diffuser 10 back and forth in the direction of the air flow. However, the same effect can be obtained by fixing the supersonic diffuser 10 and moving the supersonic nozzle 5 back and forth in the direction of the air flow. Therefore, a straight pipe section is provided on the upstream side of the supersonic nozzle 5, and the structure is such that the straight pipe section is inserted into the inside of the high pressure gas supply pipe 2 and slides, or the high pressure gas supply pipe 2 is inserted inside the straight pipe section. The supersonic nozzle 5 can be moved by inserting the supersonic nozzle 5 into the measuring chamber 6 and sliding it.
A similar effect can be obtained by providing a sliding structure in which the contact portion between the side wall and the supersonic nozzle 5 is sealed with a sealing member. Next, a fourth embodiment of the present invention will be described with reference to FIG. In FIG. 4, similar to the supersonic wind tunnel apparatus shown in FIG. configured. In this example, a sliding portion necessary for moving the supersonic diffuser was installed in the measurement chamber 6. The measurement chamber 6 is composed of a measurement chamber fixing section 24 and a measurement chamber moving section 25. Either the measurement chamber moving section 25 is inserted into the measurement chamber fixing section 24 and slides, or the measurement chamber fixing section 24 is inserted into the measurement chamber fixing section 24 and sliding. It has a structure in which it is inserted into the inside of the measurement chamber moving section 25 and slides. Note that the sliding portions of the measurement chamber moving section 25 and the measurement chamber fixing section 24 have a sliding structure sealed by a sealing member 13. The measurement chamber moving section 25 is fixed to the supersonic diffuser IO by welding or the like, and connected to the exhaust pipe via a bellows 14 on the downstream side of the enlarged flow path 9 of the supersonic diffuser 10. Wheels 26 and rails 2 are provided on the lower wall of the measurement chamber moving section 25.
7, and has a structure in which wheels 26 can move forward and backward in the direction of airflow on rails 27, and the measurement chamber fixing section 24 has an outer wall fixed to the floor with a fixing member 28. The jack 15, which uses hydraulic pressure, compressed air, etc., has one end of a part of the cylinder fixed to a fixed member 28, and the tip of the moving part is connected to the jack supporting member 16 of the measurement chamber moving part 25. Here, the measurement chamber moving section 25 and the supersonic diffuser 10 have a structure that can be moved back and forth in the direction of the airflow by operating the jack 15. At this time,
Since the sliding portions of the measurement chamber moving section 25 and the measurement chamber fixing section 24 are sealed by the sealing member 13, outside air does not leak into the measurement chamber 6 due to movement of the measurement chamber moving section 25. First, before supplying high enthalpy gas from the high pressure gas supply source to the supersonic nozzle 5, the jack 15 is actuated to move to the vicinity where the tip of the reduction flow path 7 touches the outlet of the supersonic nozzle 5, and then stopped. . Next, the high enthalpy gas stored in the high pressure gas supply source is guided to the supersonic nozzle 5 and ejected from the supersonic nozzle 5 into the measurement chamber 6 . Shock waves are generated in the measurement chamber 6, but by increasing the pressure of the high-pressure gas supply source, they pass through the constant cross-sectional area flow path of the supersonic diffuser 10 at a certain pressure and move downstream, is in the starting state. After the supersonic diffuser 10 is started, the jack 15 is actuated in the direction in which the moving part of the jack 15 extends to move the measurement chamber moving part 25 in the downstream direction of the airflow, thereby connecting the downstream side of the supersonic nozzle 5 and the contracted flow path 7. A free jet space is provided between the upstream side of the In this way, even if the measurement chamber moving section 25 moves as described above, the free jet section maintains the supersonic state. According to this embodiment, since the volume of the measurement chamber before starting the supersonic diffuser can be reduced, the kinetic energy of the gas required to discharge the gas in the measurement chamber downstream of the supersonic diffuser is small. This has the effect of making starting easier and further reducing starting pressure. In addition, in the above embodiment, instead of the bellows provided between the downstream side of the expanded flow path 9 of the supersonic diffuser 10 and the exhaust pipe 11, a cross-sectional area is provided downstream of the expanded flow path 9 as shown in FIG. A sliding structure in which a constant flow path 21 is provided and the straight pipe part 21 is inserted into the exhaust pipe 11 and slides, or a sliding structure in which the exhaust pipe 11 is inserted into the constant cross-sectional area flow path 21 and slid. The same effect can be obtained as well. Also, during this movement, the constant cross-sectional area flow path 21 and the exhaust pipe 11 are sealed with a sealing member, so
The movement of the supersonic diffuser 10 prevents gas outside the tube from entering the tube. In the above embodiment, the supersonic nozzle 5 was fixed and the supersonic diffuser 10 was moved back and forth in the direction of the airflow to reduce the pressure loss due to gas ejection from the supersonic nozzle of the free jet type supersonic wind tunnel. The same effect can be obtained even if the supersonic diffuser 10 is fixed and the supersonic nozzle 5 on the upstream side of the measurement chamber 6 is moved back and forth in the air flow direction. Therefore, a bellows is provided on the upstream side of the supersonic nozzle 5, and the contact portion between the side wall of the measurement chamber 6 and the supersonic nozzle 5 is sealed with a sealing member to form a sliding structure. You can get the same effect by moving back and forth. Or supersonic nozzle 5
A straight pipe part is provided on the upstream side of the pipe, and the straight pipe part is inserted into the inside of the high-pressure gas supply pipe 2 and slides, or the high-pressure gas supply pipe 2 is inserted into the inside of the straight pipe part and slides. The structure is designed to be movable, and the sliding part is sealed with a sealing member. Furthermore, the contact area between the side wall of the measurement chamber 6 and the supersonic nozzle 5- is sealed with a sealing member to form a sliding structure, so that the supersonic nozzle 5 can be moved back and forth in the direction of the airflow, and the same effect cannot be obtained. can. Next, a fifth embodiment of the present invention will be explained with reference to FIG. The structure used is According to this embodiment, since there are no sliding parts in the measurement chamber, there is an effect that the confidentiality of the measurement chamber can be increased. In the first to fifth embodiments, before supplying high enthalpy gas from the high pressure gas supply source to the supersonic nozzle 5, the supersonic diffuser 10 is reduced so that the tip of the flow path 7 is the outlet of the supersonic nozzle 5. The starting pressure of the supersonic diffuser 10 was lowered by supplying high enthalpy gas from this state. The supersonic diffuser 10 is started by supplying high enthalpy gas from the state in which the supersonic nozzle 5 has moved to the position where the outlet end of the supersonic nozzle 5 contacts the contraction channel 7 of the supersonic diffuser 10. Even if the pressure is lowered, the free jet area between the supersonic nozzle and the supersonic diffuser can be significantly reduced during startup of the supersonic diffuser, reducing the pressure loss that occurs when the gas flows freely. The starting pressure of the sonic diffuser can be lowered. A sixth embodiment of the present invention will be described with reference to FIG. In this embodiment, a movable diffuser 31 that slides back and forth in the flow direction of the airflow in the duct is applied to a supersonic wind tunnel that does not have a free jet part downstream of the supersonic nozzle 5, and the measurement chamber 6 and the airflow This reduces the wall friction loss between the two. The movable diffuser 31 has a slidable structure on both the upstream and downstream sides so that the movable diffuser 31 can move back and forth in the flow direction of the airflow within the measurement chamber 6. The slit 30 is a slit through which the support member 6 connecting the movable diffuser 31 and the jacker 5 moves, and is cut into a portion of the upper and lower wall surfaces of the measurement chamber 6. Jacky 15 is
A device that moves the movable diffuser 31 back and forth in the airflow direction using hydraulic pressure or compressed air.
One end of the cylinder is fixed to a jack fixing base 32 attached to the outer wall of the measurement chamber 6, and the tip of the moving part is connected to the jack supporting member 16 of the moving diffuser 31. moreover,
It has a sliding structure in which the sliding movement of the movable diffuser 31 against the inner wall of the measurement chamber 6 is sealed by a sealing member 13. Therefore, by operating the jack 15, the movable diffuser 31 can be moved back and forth in the direction of the airflow. At this time, since the inner wall of the measurement chamber 6 and the sliding part of the movable diffuser 31 are sealed by the seal member 13, the measurement chamber 6 is
No gas leaks into the duct. First, the jack 15 is operated to move the tip of the movable diffuser 31 to the vicinity where it contacts the outlet of the supersonic nozzle 5. Next, gas is caused to flow from the supersonic nozzle 5. After the movable diffuser 31 is started, the jack 15 is actuated to move it in the downstream direction of the airflow. According to this example, the distance between the supersonic nozzle and the supersonic diffuser can be reduced even in a supersonic wind tunnel apparatus without a free jet part, so that the wall friction loss between the measurement chamber and the airflow can be reduced. This has the effect of lowering the starting pressure of the supersonic diffuser. In the above embodiment, the supersonic nozzle 5 is fixed and the movable diffuser 31 is moved back and forth in the air flow direction, but the movable diffuser 31 is fixed and the supersonic nozzle 5 is moved forward and backward in the air flow direction. A similar effect can be obtained by using a structure that can be moved. Therefore, the supersonic nozzle (moving nozzle) is provided with a slidable structure on both the upstream and downstream sides of the supersonic nozzle so that it can move back and forth in the flow direction of the airflow within the measurement chamber 6. Next, a seventh embodiment of the present invention will be described with reference to FIG. In this embodiment, a shielding pipe 1 shields the ejection part between the outlet end of the supersonic nozzle 5 and the artificial end of the supersonic diffuser 10 from the measurement chamber.
2 moves back and forth in the flow direction of the airflow, making it possible to vary the free jet area. The shielding pipe 12 has a structure that allows it to be moved back and forth in the direction of the airflow by a jack 15 using hydraulic pressure, compressed air, or the like. The jacker 5 has one end of the cylinder part fixed to the inner wall of the side wall of the measurement chamber 6, and the tip of the moving part connected to the shielding tube 12.
It is connected to the jack support material 16 of the. Furthermore, the contact portion between the shielding tube 12 and the supersonic diffuser 10 and the shielding tube 12
The contact portion between the supersonic nozzle 5 and the supersonic nozzle 5 has a sliding structure sealed by a seal member 13. Furthermore, since the shielding tube 12 is supported by a sliding bearing 17, it has a structure in which it can only move forward and backward in the direction of the airflow. Therefore, by operating the jack 15 attached to the inner wall of the measurement chamber 6, the shielding tube 12 can be moved back and forth in the direction of the airflow. At this time, since the contact area between the shielding tube 12 and the supersonic diffuser 10 and the contact area between the shielding tube 12 and the supersonic nozzle 5 are sealed by the sealing member 13, the inside of the measurement chamber 6 is sealed until the shielding tube 12 is moved. Gas shielding tube 1
2 No leakage inside. First, before supplying high enthalpy gas from the high pressure gas supply source to the supersonic nozzle 5, the jack 15 is actuated so that the tip of the shielding tube 12 is connected to the sealing member 13 at the outlet of the supersonic nozzle 5.
Move until it touches and stop. Next, the high enthalpy gas stored in the high pressure gas supply source is guided to the supersonic nozzle 5,
It is ejected from the supersonic nozzle 5 into the shielding pipe 12. Shock waves are generated within the shielding tube 12, but by increasing the pressure of the high-pressure gas supply source, at a certain pressure the shock waves pass through the constant cross-sectional area channel 8 of the supersonic diffuser 10 and move downstream, causing the The sonic diffuser 10 is in the starting state. After the supersonic diffuser 10 starts, the moving part of the jack 15 operates in the direction of contraction to move the shielding tube 12 in the downstream direction of the airflow, and between the downstream side of the supersonic nozzle 5 and the upstream side of the supersonic diffuser 10. Provide a free jet space. In this way, even if the supersonic diffuser 10 moves as described above, the free jet section maintains the supersonic state. According to this embodiment, when starting the supersonic diffuser,
Since the free jet area between the supersonic nozzle and the supersonic diffuser can be significantly reduced, the pressure loss that occurs when the gas flows freely can be reduced, and the starting pressure of the supersonic diffuser can be lowered. Furthermore, since the sliding part is located inside the measurement chamber, the pressure difference is smaller than in a structure in which the sliding part is located outside the measurement chamber, so there is an effect that the sealing structure of the sealing part becomes easier. In the above embodiment, the shielding tube 12 is connected to the supersonic diffuser 10.
However, on the contrary, the shielding pipe 12
A similar effect can be obtained by using a structure in which the supersonic nozzle 5 is moved in the direction of the supersonic nozzle 5. Next, an eighth embodiment of the present invention will be described with reference to FIG. This embodiment has a structure in which the reduction channel 7 can be opened and closed vertically or horizontally with respect to the air flow direction by a jack 15 using oil pressure, compressed air, etc., and by opening and closing the reduction channel 7, the supersonic nozzle 5 The ejection area at the outlet end and the supersonic diffuser inlet end can be made variable. The jack 15 has one end of the cylinder part fixed to the inner wall of the side wall of the measurement chamber 6, and the tip of the moving part is connected to the jack support member 16 of the contraction channel 7. Further, the contact portion between the reduction channel 7 and the supersonic nozzle 5 is sealed with a seal member 13. In addition, a jack support material 1 is provided in the reduction channel 7.
The guide 1 on which 6 moves is the attachment. Therefore, by operating the jack 15 attached to the inner wall of the measurement chamber 6, the reduction channel 7 opens vertically and horizontally with respect to the flow direction of the airflow, so that the supersonic nozzle 5 and the reduction channel 7 are separated from each other. . At this time, since the contact portion between the reduction flow path 7 and the supersonic nozzle 5 and the reduction flow path 7 and the constant cross-sectional area flow path 8 are sealed by the sealing member 13, the measurement chamber 6 is closed until the reduction flow path 7 is opened.
Internal gas does not leak into the reduction channel 7. First, before supplying high enthalpy gas from the high pressure gas supply source to the supersonic nozzle 5, the jack 15 is operated to close the reduction channel 7 and bring it into contact with the supersonic nozzle 5. Next, the high enthalpy gas stored in the high pressure gas supply source is guided to the supersonic nozzle 5 and ejected from the supersonic nozzle 5 into the contraction channel 7 . A shock wave is generated in the contraction channel 7, but by increasing the pressure of the high-pressure gas supply source, at a certain pressure, the shock wave passes through the constant cross-sectional area channel 8 of the supersonic diffuser 10 and moves downstream, The supersonic diffuser 10 is in a starting state. After the supersonic diffuser 10 starts, the jack 15
The moving part operates in the direction of contraction to open the contraction channel 7, and a free jet space is provided between the downstream side of the supersonic nozzle 5 and the upstream side of the supersonic diffuser 10. In this way, even if the supersonic diffuser 10 moves as described above, the free jet section maintains the supersonic state. According to this embodiment, when starting the supersonic diffuser,
Since the free jet area between the supersonic nozzle and the supersonic diffuser can be significantly reduced, the pressure loss that occurs when the gas flows freely can be reduced, and the starting pressure of the supersonic diffuser can be lowered. Furthermore, since the seal part is located inside the measurement chamber, the pressure difference is smaller than in a structure in which the seal part is located outside the measurement chamber, so there is an effect that the seal structure of the seal part becomes easier. In addition, in FIG. 7, the free jet area between the supersonic nozzle and the supersonic diffuser is connected to the measurement chamber 6 by the shielding pipe 12.
Although the shielding tube 12 is moved from the shielded state, the same effect as in the above embodiment can be obtained even if the shielding tube 12 is moved from a slightly distant state. Also, the 8th
In the figure, the supersonic nozzle 5 and the supersonic diffuser are opened from a state of complete contact, but the same effect as in the above embodiment can be obtained even if the supersonic nozzle 5 and the supersonic diffuser are opened from a slightly separated state. Note that although FIGS. 1 to 8 show examples in which a jack using hydraulic pressure, compressed air, etc. is applied as a moving mechanism for the supersonic diffuser, the supersonic nozzle, and the shielding pipe, other moving means may also be used. The same effect can be obtained by using . Hereinafter, the moving mechanism of a supersonic diffuser will be explained as an example. In FIG. 9, a rotating body such as an electric motor is used as the drive source. The screw 34 connected to the electric motor 33 is rotated by the rotation of the electric motor 33, and the nut 3 fixed to the nut holder 35 is rotated by the rotation of the electric motor 33.
The force generated by 6 moves the supersonic diffuser 10 back and forth. here. 37 is a bearing that absorbs the rotation of the screw 34, and 38 is a fixing member that fixes the bearing. Another mechanism for moving a supersonic diffuser using a rotating body such as an electric motor is a method of combining a rack and a pinion. As an example, the rack is mounted and fixed on the supersonic diffuser side, the pinion is connected to the electric motor, and the pinion is fixed on a fixed base or the like at a position where it meshes with the rack. When the pinion is driven by an electric motor, the rack receives force from the pinion and is moved, so the supersonic diffuser also moves. In this method, the same effect can be obtained even if the pinion and motor are fixed to the supersonic diffuser and the rack is fixed to a fixed stand. Another method using a rotating body such as an electric motor is the 10th method.
There is one that uses a pulley 39 and a belt 40 as shown in the figure. Two pulleys 39 are installed at a distance greater than the moving range of the supersonic diffuser 10, and the two pulleys 39 are connected by a belt 40. Also, belt 40
A connecting member 41 connecting the supersonic diffuser 10 and the belt 40 is provided. In this state, by driving one of the pulleys 39 with the electric motor 33, the pulley 39
The belt 40 is moved due to the rotation of the belt 40. Therefore, the connecting member 41 connected to the belt 40 and the supersonic diffuser 10 can be moved. Here, 42 is a guide for the sliding bearing 17 to move in the front and back direction, 43 is a guide holder, 44 is a frame for fixing the pulley and the electric motor, 45 is a support member that supports the shaft of the pulley, and 46 is a supersonic diffuser 10. This is a connecting member that connects the bearings 17. According to this embodiment, there is an effect that the moving distance of the supersonic diffuser can be increased. Next, another embodiment of the means for moving the supersonic diffuser 10 is shown in FIG. In the present invention, in the mechanism for moving the supersonic diffuser 10 back and forth, the spring holder 47 and the connecting member 49 are connected by the spring 50. Further, to prevent the spring 50 from slackening, the spring support rod 51 is passed through the spring 50, and the negative end is passed through the spring 50 so as not to come into contact with the connecting member 49, and is fixed in the measurement chamber, and the other end is fixed to the spring holder. First, the jack 15 is operated to move the supersonic diffuser 10 to a predetermined position. There is a stopper 52 at that position, and by fixing the connecting member 49 with the stopper 52, the supersonic diffuser 10 is fixed. After that, the jacket 15 is contracted. Next, high enthalpy gas is introduced from the high pressure gas supply source to the supersonic nozzle, and after the supersonic diffuser 10 is started, the stopper 52 is removed. Stopper 5
By removing 2, the spring 5 that had been stretched
0 contracts, the supersonic diffuser 10 moves in the downstream direction of the airflow and stops at the position of the spring holder 47 as the connecting member 49 hits the spring holder 47. A damper 53 is attached to the tip of the spring holder 47 to absorb shock when the vehicle stops. After stopping, supersonic diffuser 10
The connecting member 49 is fixed by a fixing stopper 54 to prevent it from rebounding. The stopper 54 is at the position indicated by the solid line before the supersonic diffuser 10 moves in the downstream direction of the airflow, and moves counterclockwise in conjunction with the movement of the supersonic diffuser 10 in the downstream direction of the airflow. When the diffuser 10 is stopped, it moves to the position shown by the dotted line. Further, the spring 50 is housed within the spring holder 47. According to this embodiment, there is an effect that the moving time of the supersonic diffuser can be shortened. The operating methods of the first to eighth embodiments of the present invention are described in the first embodiment.
This embodiment, which will be explained with reference to FIG.
This relates to the operating method of the embodiment. Before supplying gas from a high pressure gas source, first, the supersonic diffuser 1
0 in the upstream direction of the airflow, the computer 5
9 sends a control signal to the drive control device 19. Drive control device! ! 19 receives this signal and operates the drive device 15 to move the supersonic diffuser 10 in the upstream direction of the flow,
It moves to a position where the free jet space between the supersonic nozzle 5 and the supersonic diffuser 10 is eliminated and automatically stops. After moving the supersonic diffuser 10, gas is supplied from a high pressure gas supply source. A plurality of pressure sensors 58 are installed in advance in the supersonic diffuser 10 or the measurement chamber 6, and the output values of these pressure sensors 58 are sent to a computer 59.
A previously known supersonic diffuser 10
The starting of the supersonic diffuser 10 is determined by comparing it with the static pressure distribution data when the supersonic diffuser 10 is started. If it is determined that the supersonic diffuser 10 has started, the computer 59 sends a control signal to the drive control device 19 that moves the supersonic diffuser 10. The drive control device 19 operates the drive device 15 in response to this signal, moves the supersonic diffuser 10 to a predetermined position in the downstream direction of the flow, and automatically stops it. After starting supersonic diffuser 10,
The time required to separate the supersonic nozzle 5 and the supersonic diffuser 10 in the direction of the airflow is determined by the pressure loss that occurs when they are separated to create a free jet space, and the area of the space blown out from the exit of the supersonic nozzle 5. Since the pressure balance in the supersonic wind tunnel may be disrupted due to a sudden increase in the value of In the first to eighth embodiments of the present invention, except for the sixth embodiment, all others relate to free jet type wind tunnels, but in the case of a free jet type wind tunnel, the test specimen was inserted into the free jet part and tested. Often investigates the aerodynamic properties of the body. The following is an example in which a test specimen is inserted into the free jet section. First, before supplying gas from the high-pressure gas supply source, the test specimen 55 is installed in a place where the airflow ejected from the supersonic nozzle 5 does not directly touch the test specimen, for example, under the supersonic diffuser 10. Set it lower than the wall. Here, the test specimen 55 has a structure that allows it to be moved in the vertical direction by a jack 56 using hydraulic pressure, compressed air, or the like. One end of the cylinder of the jack 56 is fixed to the inner surface of the lower wall of the measurement chamber 6, and the tip of the moving part is connected to a fixed base 57 on which the test specimen 55 is set in advance. Further, a plurality of pressure sensors 58 for detecting pressure data are installed in the reduced flow path 7, constant cross-sectional area flow path 8, enlarged flow path 9, or measurement chamber 6 of the supersonic diffuser 10. Next, in order to move to a position where there is no free jet space between the supersonic nozzle 5 and the supersonic diffuser 10, the computer 59 sends a control signal for the supersonic diffuser IO to move in the upstream direction of the airflow to the drive control device! Send to 19. The drive control device 19 receives this signal and controls the drive bag! (e.g. jack). The supersonic diffuser 10 is moved in the upstream direction of the flow to a position where the free jet space between the supersonic nozzle 5 and the upper part of the supersonic diffuser is eliminated, and then automatically stopped. After moving the supersonic diffuser 10, gas is supplied from the high pressure gas supply source to the supersonic nozzle 5. The gas expanded by the supersonic nozzle 5 is ejected into the measurement chamber 6 and exhausted through the supersonic diffuser 10 located downstream of the measurement chamber 6. Here, starting of the supersonic diffuser 10 can be determined by examining static pressure distribution data of the supersonic diffuser 10 or the measurement chamber 6. Supersonic diffuser 1
Alternatively, the output values of the plurality of pressure sensors 58 installed in the measurement chamber 6 are input into the computer 59, and data of the static pressure distribution at the time of starting the supersonic diffuser 10, which is known in advance, is stored in the computer. The data and the static pressure distribution data are automatically compared and evaluated by the computer 59, and when it is determined that the supersonic diffuser 10 is in the starting state, the computer 59 controls the drive device 15 that moves the supersonic diffuser 10. A control signal is sent to the drive control bag W19, and the drive control device 19 receives this signal and operates the drive device 15 to move the supersonic diffuser 10 to a predetermined position in the downstream direction of the flow and automatically stop it. Thereafter, the test object moving jack 56 is automatically operated to set the test object 55 in a predetermined position in the supersonic flow. Further, if it is determined that the supersonic diffuser 10 is not in the starting state, the supersonic diffuser 1
Do not move 0. All these operations can now be performed automatically. According to this embodiment, since all operations can be performed automatically, it is possible to save labor in operating the wind tunnel. In the above embodiment, the supersonic nozzle 5 is fixed and the supersonic diffuser 10 is moved back and forth in the flow direction of the airflow. The operating method of moving the tube back and forth in the flow direction is shown below. Before supplying gas from the high-pressure gas supply source, the computer 59 first sends a control signal to the drive control device 19 in order to move the supersonic nozzle 5 in the downstream direction of the airflow. Upon receiving this signal, the drive control device 19 operates the drive device 15 to move the supersonic nozzle 5 in the downstream direction of the airflow.
It moves to a position where the free jet space between the supersonic nozzle 5 and the supersonic diffuser 10 is eliminated and automatically stops. After moving the supersonic nozzle 5, gas is supplied from a high pressure gas supply source. The supersonic diffuser 10 or the measurement chamber 6 includes:
A plurality of pressure sensors 58 are installed in advance, and the output values of these pressure sensors 58 are imported into a computer 59 and compared with previously known static pressure distribution data when the supersonic diffuser 10 is started. It is determined whether the supersonic diffuser 10 is started. If it is determined that the supersonic diffuser 10 has started, the computer 5
9 sends a control signal to a drive control device 19 that moves the supersonic nozzle 5. The drive control device 19 operates the drive device 15 in response to this signal, moves the supersonic nozzle 5 to a predetermined position in the upstream direction of the flow, and automatically stops it. After starting the supersonic diffuser 10, the time required to separate the supersonic nozzle 5 and the supersonic diffuser 10 in the direction of the airflow is determined by the pressure loss that occurs when the free jet space is created by separating them, and the pressure loss between the supersonic nozzle 5 and the supersonic nozzle 5. Since the pressure balance in the supersonic wind tunnel may collapse due to the sudden increase in the area of the space emitted from the exit, the shock wave that has moved upstream of the supersonic nozzle 5 is gradually released so that it does not return to the measurement chamber. . In the first to eighth embodiments of the present invention, except for the sixth embodiment, all others relate to free jet type wind tunnels, but in the case of a free jet type wind tunnel, the test specimen was inserted into the free jet part and tested. Often investigates the aerodynamic properties of the body. The following is an example in which a test specimen is inserted into the free jet section. First, before supplying gas from the high-pressure gas supply source, the test object 55 is installed in a place where the air flow ejected from the supersonic nozzle 5 does not directly touch the test object 55, for example, under the supersonic diffuser 10. Set it lower than the wall. Here, the test specimen 55 has a structure that allows it to be moved in the vertical direction by a jack 56 using hydraulic pressure, compressed air, or the like. One end of the cylinder of the jack 56 is fixed to the inner surface of the lower wall of the measurement chamber 6, and the tip of the moving part is connected to a fixed base 57 on which the test specimen 55 is set in advance. In addition, the reduction flow path 7 of the supersonic diffuser lO
, a plurality of pressure sensors 58 for detecting pressure data are installed in the constant cross-sectional area flow path 8, the enlarged flow path 9, or the measurement chamber 6. Next, in order to move to a position where there is no free jet space between the supersonic nozzle 5 and the supersonic diffuser 10, the computer 59 sends a control signal to the drive control device 19 to cause the supersonic nozzle 5 to move in the downstream direction of the airflow. The drive control device 19 receives this signal and controls the drive device 15.
(for example, a jack) to move the supersonic nozzle 5 in the downstream direction of the flow, move to a position where the free jet space between the supersonic nozzle 5 and the supersonic diffuser 10 is eliminated, and automatically stop. After moving the supersonic nozzle 5, gas is supplied to the supersonic nozzle 5 from a high pressure gas supply source. The gas expanded by the supersonic nozzle 5 is ejected into the measurement chamber 6. The air is exhausted through a supersonic diffuser 10 located downstream of the measurement chamber 6. Here, starting of the supersonic diffuser 10 can be determined by examining static pressure distribution data of the supersonic diffuser 10 or the measurement chamber 6. The output values of the supersonic diffuser 10 or the plurality of pressure sensors 58 installed in the measurement chamber 6 are input into the computer 59, and the data of the static pressure distribution at the time of starting the supersonic diffuser 10, which is known in advance, is stored in the computer. Then, the computer 59 automatically compares and evaluates this data with the static pressure distribution data, and when it is determined that the supersonic diffuser 10 is in the starting state, the computer 59 moves the supersonic nozzle 5! 15
A control signal is sent to the drive control device 19 that controls the flow, and the canter control device engineer 9 receives this signal and operates the drive device 15 to move the supersonic nozzle 5 to a predetermined position in the upstream direction of the flow. Stop at. Thereafter, the test object moving jack 56 is automatically operated to set the test object 55 in a predetermined position in the supersonic flow. Further, if it is determined that the supersonic diffuser 10 is not in the starting state, the supersonic nozzle 5 is not moved. All these operations can now be performed automatically. [Effects of the Invention] According to the present invention, when starting a supersonic wind cylinder, a means for reducing the distance between the supersonic nozzle and the supersonic diffuser is provided to significantly reduce the free jet region, and the gas flows in a free jet. Since the pressure loss that sometimes occurs can be reduced and the starting pressure of the supersonic diffuser can be lowered, the cost of equipment and power for supplying high enthalpy gas can be reduced.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a supersonic wind tunnel apparatus showing a first embodiment of the present invention, FIG. 2 is a longitudinal cross-sectional view of a supersonic wind tunnel apparatus showing a second embodiment of the present invention, and FIG. 3 is a longitudinal cross-sectional view of a supersonic wind tunnel apparatus showing a second embodiment of the present invention. FIG. 4 is a longitudinal cross-sectional view of a supersonic wind tunnel apparatus showing a third embodiment of the present invention, FIG. 5 is a longitudinal cross-sectional view of a supersonic wind tunnel apparatus showing a fourth embodiment of the present invention, and FIG. FIG. 6 is a longitudinal cross-sectional view of a supersonic wind tunnel apparatus showing a sixth embodiment of the present invention, and FIG. 7 is a longitudinal cross-sectional view of a supersonic wind tunnel apparatus showing a seventh embodiment of the present invention. FIG. 9 is a front view of another moving mechanism of the supersonic diffuser of the present invention, and FIG. FIG. 11 is a front view of another moving mechanism of the supersonic diffuser of the present invention, and FIG. 12 is a front view of another moving mechanism of the supersonic diffuser of the present invention. FIG. 13 is a longitudinal cross-sectional view of a conventional free jet type supersonic wind tunnel device; FIG. 14 is a diagram showing the relationship between the startup and operation of the supersonic diffuser and the total pressure upstream of the supersonic nozzle;
FIG. 15 is a diagram showing the relationship between the distance between the supersonic nozzle and the supersonic diffuser and the total pressure upstream of the supersonic nozzle at the time of starting the supersonic diffuser. Explanation of symbols 2... High pressure gas supply pipe, 4... Nozzle throat, 5
. . . Supersonic nozzle, 6. Measurement chamber, 7. Reduction flow path, 8. Constant cross-sectional area flow path, 9. Expansion flow path. 10...Supersonic diffuser, 11...Exhaust pipe, 1
2... Shielding pipe, 13... Seal member, 14... Bellows, 15... Jacket, support material 16° 17...
Bearing, 19...Longitudinal motion control device, 21...Straight pipe section, 2
2... Diffuser moving part, 23... Diffuser fixing part, 24... Measuring chamber fixing part, 25... Measuring chamber fixing part, 26... Wheel, 27... Rail, 28...
Fixing material, 29... Measuring chamber bellows, 30... Slit, 31... Moving diffuser, 32... Jacket fixing base, 33... Electric motor, 34... Screw, 35...
・Nut holder, 36... Nut, 37... Bearing,
38...Fixing material, 39...Pulley, 40...Belt, 50...Spring, 55...Test specimen, 58...
Pressure sensor, 59...computer. Ba 2

Claims (1)

[Claims] 1. A gas supply source supplying a high enthalpy gas, a gas supply pipe connected at one end to the gas supply source, and one connected to the gas supply pipe and having a constriction on the inside; a supersonic nozzle having an open end and in which the high enthalpy gas expands and is ejected;
a supersonic diffuser having one opening end facing the opening end of the supersonic nozzle and comprising a contracting flow path, a constant cross-sectional area flow path, and an expanding flow path; and shielding the supersonic nozzle and the supersonic diffuser from outside air. In a high enthalpy supersonic wind tunnel apparatus having a measurement chamber made of a shield and an exhaust pipe connected to an expanded flow path of the supersonic diffuser, an open end of the supersonic nozzle and an open end of the supersonic diffuser that face each other, A high enthalpy supersonic wind tunnel device characterized by having a means for changing the distance between. 2. The means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser is means for causing the opening end of the supersonic nozzle and the opening end of the supersonic diffuser to face each other and approach or separate from each other. The high enthalpy supersonic wind tunnel apparatus according to claim 1, characterized in that: 3. The means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser is connected to a means for moving a reduction channel of the supersonic diffuser provided in the measurement chamber and the reduction channel. 2. The high enthalpy supersonic wind tunnel apparatus according to claim 1, further comprising a slidable double pipe provided in a constant cross-sectional area flow path. 4. The means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser includes means for moving the supersonic nozzle provided in the measurement chamber and gas supply upstream of the supersonic nozzle. The high enthalpy supersonic wind tunnel apparatus according to claim 1, further comprising a slidable double pipe provided in the pipe. 5. The means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser includes means for moving a constant cross-sectional area flow path of the supersonic diffuser, and a means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser. The high enthalpy device according to claim 1, further comprising a sliding portion provided between the channel and the measurement chamber wall, and a bellows provided between the enlarged flow channel of the supersonic diffuser and the exhaust pipe. Supersonic wind tunnel equipment. 6. The means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser includes means for moving the supersonic nozzle and a slide provided between the supersonic nozzle and the wall of the measurement chamber. The high enthalpy supersonic wind tunnel apparatus according to claim 1, further comprising a moving part and a bellows provided between the supersonic nozzle and the gas supply pipe. 7. In place of the bellows, a double-structured sliding section is provided, which is connected to a straight pipe section on the downstream side of the enlarged channel of the supersonic diffuser and connected to the exhaust pipe.
High enthalpy supersonic wind tunnel device described in. 8. In place of the bellows, a double-structured sliding section is provided, which is connected to the straight pipe section on the upstream side of the contracting flow path of the supersonic nozzle and connected to the gas supply pipe. High enthalpy supersonic wind tunnel device described in. 9. The means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser is configured to change the distance between the measurement chamber wall fixed to the supersonic nozzle and the measurement chamber wall fixed to the supersonic diffuser. A claim characterized by comprising a sliding part provided between, a means for moving the measurement chamber on the side of the supersonic diffuser, and a bellows provided between the enlarged flow path of the supersonic diffuser and the exhaust pipe. The high enthalpy supersonic wind tunnel apparatus according to item 1. 10. The means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser is configured to change the distance between the measurement chamber wall fixed to the supersonic nozzle and the measurement chamber wall fixed to the supersonic diffuser. 2. The method according to claim 1, further comprising: a sliding part provided between the gas supply tube, a means for moving the measurement chamber on the supersonic nozzle side, and a bellows provided between the supersonic nozzle and the gas supply pipe. High enthalpy supersonic wind tunnel apparatus described. 11. The high enthalpy supersonic wind tunnel apparatus according to claim 9, characterized in that a bellows is provided in place of the sliding part. 12. The high enthalpy supersonic wind tunnel apparatus according to claim 10, characterized in that a bellows is provided in place of the sliding part. 13. Claim 9, characterized in that, in place of the bellows, a sliding part with a double structure is provided, which is configured by connecting a straight pipe part to the downstream side of the enlarged flow path of the supersonic diffuser and connecting it to the exhaust pipe. The high enthalpy supersonic wind tunnel apparatus according to claim 11. 14. Claim 1 characterized in that, in place of the bellows, a double-structured sliding part is provided, which is configured by connecting a straight pipe part to the upstream side of the contracting flow path of the supersonic nozzle and connecting it to the gas supply pipe.
0. The high enthalpy supersonic wind tunnel apparatus according to claim 12. 15. The means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser includes a duct-shaped measurement chamber connected downstream of the supersonic nozzle, and a means for slidingly inserted into the measurement chamber. Claim 1, further comprising: a movable diffuser, means for moving the movable diffuser, and a sealing member provided on the inside of the duct-shaped measurement chamber.
High enthalpy supersonic wind tunnel device described in. 16. The means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser is such that one side is slidably inserted into the gas supply pipe and the other side is slidably inserted into the duct-shaped measurement chamber. 2. The measuring chamber according to claim 1, further comprising a movable nozzle to be inserted, a means for moving the movable nozzle, the gas supply pipe that slides on the movable nozzle, and a sealing member provided inside the measurement chamber. High enthalpy supersonic wind tunnel equipment. 17. The means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser includes a shielding pipe into which the supersonic nozzle and the supersonic diffuser are slidably inserted so as to face each other; The high enthalpy supersonic wind tunnel apparatus according to claim 1, further comprising means for moving the shielding tube in the direction of insertion of the supersonic nozzle or the supersonic diffuser. 18. The means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser is capable of freely rotating a reduced flow path consisting of a plurality of members and one constant cross-sectional area flow path of the supersonic diffuser. The high enthalpy supersonic wind tunnel apparatus according to claim 1, further comprising: a member connected to the plurality of members; and means for rotating the plurality of members. 19. The means for changing the distance between the opening end of the supersonic nozzle and the opening end of the supersonic diffuser includes a plurality of pressure sensors provided in the supersonic diffuser or the measurement chamber;
The static pressure distribution of the supersonic diffuser or the measurement chamber output by the plurality of pressure sensors is input and compared with a predetermined static pressure distribution at startup, and if it is determined that the supersonic nozzle or the measurement chamber has started. 19. The high enthalpy supersonic wind tunnel apparatus according to claim 1, further comprising a control means for moving the measurement chamber or the supersonic diffuser. 20. Perform a specified wind tunnel experiment by expanding high enthalpy gas using a supersonic nozzle and ejecting it into a measurement chamber at supersonic speed. In the method of operating an enthalpy supersonic wind tunnel, the high enthalpy gas is supplied to the supersonic nozzle so that a shock wave generated in the supersonic nozzle passes through a constant cross-sectional area flow path of the supersonic diffuser, and at the same time, the supersonic nozzle A method of operating a high-enthalpy supersonic wind tunnel characterized by changing the distance between the open end of the diffuser and the open end of the supersonic diffuser. 21. The method of operating a high enthalpy supersonic wind tunnel according to claim 20, wherein the passage of the shock wave is determined based on the static pressure distribution output from the supersonic diffuser or a plurality of pressure sensors provided in the measurement chamber.