CN117030182A - Variable Mach number wind tunnel experimental device based on jet flow and suction structure - Google Patents
Variable Mach number wind tunnel experimental device based on jet flow and suction structure Download PDFInfo
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- CN117030182A CN117030182A CN202311023810.4A CN202311023810A CN117030182A CN 117030182 A CN117030182 A CN 117030182A CN 202311023810 A CN202311023810 A CN 202311023810A CN 117030182 A CN117030182 A CN 117030182A
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- 230000008602 contraction Effects 0.000 claims abstract description 29
- 239000007921 spray Substances 0.000 claims description 57
- 238000002474 experimental method Methods 0.000 claims description 22
- 238000007789 sealing Methods 0.000 claims description 15
- 230000003068 static effect Effects 0.000 claims description 13
- 238000010586 diagram Methods 0.000 description 12
- 230000008859 change Effects 0.000 description 9
- 238000005507 spraying Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- 230000001105 regulatory effect Effects 0.000 description 5
- 230000035939 shock Effects 0.000 description 5
- 230000007246 mechanism Effects 0.000 description 4
- 238000005086 pumping Methods 0.000 description 4
- 238000010276 construction Methods 0.000 description 3
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009530 blood pressure measurement Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000013011 mating Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
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- 238000004088 simulation Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M9/00—Aerodynamic testing; Arrangements in or on wind tunnels
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M9/00—Aerodynamic testing; Arrangements in or on wind tunnels
- G01M9/02—Wind tunnels
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M9/00—Aerodynamic testing; Arrangements in or on wind tunnels
- G01M9/02—Wind tunnels
- G01M9/04—Details
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M9/00—Aerodynamic testing; Arrangements in or on wind tunnels
- G01M9/06—Measuring arrangements specially adapted for aerodynamic testing
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract
The invention relates to a Mach number variable wind tunnel experimental device based on a jet flow and suction structure, which comprises an air source device, a vacuum device, a gas tank, a wind tunnel formed by sequentially connecting a contraction section, an air inlet section, a jet pipe section and an experimental section, wherein the jet pipe section is formed by surrounding a symmetrically arranged left side plate, a symmetrically arranged right side plate, an upper section and a lower section, an inner flow passage of the jet pipe section comprises a jet pipe contraction section, a throat and a jet pipe expansion section which are sequentially arranged, circular air holes which are respectively arranged in a determinant way are respectively arranged on cambered surfaces of the upper section and the lower section corresponding to the throat, the circular air holes are connected with the jet flow suction device, the jet flow suction device comprises an air collecting cavity, a pipeline connected with the air collecting cavity and an electromagnetic valve connected with the tail end of the pipeline, a pneumatic throat can be formed in the jet pipe section through on-off cutting of the electromagnetic valve hole site, and Mach number variable in the inner flow passage of the experimental section is realized through changing the ratio of the throat area to the outlet area of the jet pipe expansion section.
Description
Technical Field
The invention relates to the field of aerodynamic experiment devices, in particular to a Mach number variable wind tunnel experiment device based on jet flow and suction structures.
Background
With the continuous development of high Mach number aircrafts, wide-speed-domain flight is a necessary capability of novel aircrafts, flight Mach number changes, flight performance changes accordingly, and to accurately obtain experimental data, ground simulation equipment is required to have various flight Mach numbers. In a supersonic nozzle, different mach numbers correspond to different expansion ratios, i.e., the ratio of nozzle exit area to throat area. At present, the research of a variable Mach number wind tunnel scheme in a jet pipe section mainly comprises flexible wall type and symmetrical open-close type. The flexible wall type Mach number changing wind tunnel scheme adopts a series of pistons to move up and down so as to drive the wall surface of the spray pipe to controllably deform, thereby changing the Mach number of the spray pipe flow field. The symmetrical open-close type Mach number variable wind tunnel scheme adopts an up-and-down symmetrical wall fixing spray pipe, the spray pipe profile takes one end of the spray pipe as a rotating shaft, and the other end of the spray pipe moves up and down to change the shrinkage ratio of the spray pipe, so that the Mach number of the flow field of the spray pipe is changed.
The existing Mach number variable wind tunnel scheme mainly has the following defects: (1) the mechanical mechanism is complex to operate: if the spray pipe adopts a flexible wall surface, the flexible wall surface multipoint actuating mechanism and the control method are very complex, so that the flow field of the spray pipe is difficult to continuously and accurately control; (2) line changes lead to flow field distortions: if the jet pipe adopts a rigid body to rotate the wall surface, the selected profile change can lead to flow field distortion, so that the single jet pipe Mach range is difficult to break through 2 Mach numbers and difficult to cross high Mach numbers. (3) The actual mechanism is limited by time when running, the process of changing the Mach number is longer, and the Mach number is difficult to realize in a shorter time.
Disclosure of Invention
The invention aims to overcome the defects and provide a variable Mach number wind tunnel experimental device based on a jet flow and suction structure.
In order to achieve the above purpose, the present invention adopts the following technical scheme: the device comprises a wind tunnel formed by sequentially connecting a contraction section, an air inlet section, a spray pipe section and an experimental section, wherein the central axes of the contraction section, the air inlet section, the spray pipe section and the experimental section are identical, and the internal flow channels of the contraction section, the air inlet section, the spray pipe section and the experimental section are sequentially communicated to form a gas flow channel of the wind tunnel; the jet pipe section is formed by surrounding a left side plate, a right side plate and an upper section and a lower section which are symmetrically arranged, the end surfaces of the upper section and the lower section, which are close to each other, are outwards convex cambered surfaces, the inner flow passage of the jet pipe section comprises a jet pipe contraction section, a throat and a jet pipe expansion section which are sequentially arranged, circular air holes which are arranged in a determinant manner are respectively arranged on the cambered surfaces of the upper section and the lower section corresponding to the throat, the circular air holes are connected with a jet flow suction device, the jet flow suction device comprises an air collecting cavity, a pipeline connected with the air collecting cavity and an electromagnetic valve connected with the tail end of the pipeline, a pneumatic throat can be formed in the jet pipe section through on-off cutting of the electromagnetic valve hole site, and the Mach number change of the flow passage inside the experimental section is realized through changing the ratio of the area of the throat to the area of the outlet of the jet pipe expansion section;
the air source device comprises an air compressor, a first pressure air storage tank, a first air pipe connected with the air compressor and the first pressure air storage tank, a second air pipe connected with the first pressure air storage tank and the air collection cavity, a one-way valve arranged on the first air pipe and a pressure reducing valve arranged on the second air pipe, wherein the second air pipe is a hard pipeline;
the vacuum device comprises a vacuum pump, a second pressure air storage tank, a third air pipe for communicating the vacuum pump with the second pressure air storage tank, a vacuum valve arranged on the third air pipe and a fourth air pipe for communicating the second pressure air storage tank with an internal flow channel of the spray pipe section;
the air tank is communicated with the contraction section through a fifth air pipe, and a one-way ball valve is arranged on the fifth air pipe.
The experimental section comprises a pitot tube, one end of the pitot tube, which is provided with a pressure measuring hole, is positioned in an internal flow channel of the experimental section, pressure sensors are respectively arranged on a static pressure pipe and a total pressure pipe of the pitot tube, and the pressure sensors are connected with a feedback control system.
The whole experimental section is square, a groove is formed in the upper surface of the experimental section downwards, a notch communicated with a flow channel in the experimental section is formed in the bottom of the groove, and the notch is sealed inside and outside the experimental section through a sealing plate and a sealing ring; the pitot tube penetrates through the sealing plate, the pitot tube forms sealing with the sealing plate through the O-shaped ring, and the pressure sensor is connected with the feedback control system through a wire.
The upper section bar and the lower section bar respectively include the first section bar corresponding with spray tube shrink section, the second section bar corresponding with the throat and the third section bar corresponding with spray tube expansion section, the second section bar include the first fixed part of being connected with first section bar, the second fixed part of being connected with third section bar, connect the arc of first fixed part and second fixed part bottom and connect the apron at first fixed part and second fixed part top, the gas collecting chamber pass through the lower face of first fixed cardboard and second fixed cardboard connection at the apron, and be equipped with the inlet port with the inside intercommunication of gas collecting chamber on the apron.
The pipeline include from last first order busbar, second level busbar and the tertiary busbar of arranging down in proper order, first order busbar pass through hose and gas collection chamber intercommunication, first order busbar and second level busbar between, all pass through hard tube connection between second level busbar and the tertiary busbar.
The solenoid valve be two three-way valve, the solenoid valve include first through-hole at top, second through-hole and third through-hole, fourth through-hole, the fifth through-hole of bottom, wherein: the first through hole is connected with the outlet of the third-stage busbar through a hard pipe, and the diameter of each through hole on the electromagnetic valve is larger than that of the circular wind hole.
The electromagnetic valves are arranged in parallel in a plurality of rows, blind grooves for installing the electromagnetic valves are formed in the arc-shaped plates, any two rows of electromagnetic valves are selected for spraying and sucking to the throat, and the circular air holes are formed in the bottoms of the blind grooves.
The internal flow passage of the contraction section is a horn-shaped flow passage with a large opening and a small outlet, the internal flow passage of the air inlet section is a rectangular flow passage, the internal flow passage of the spray pipe section is a contraction-expansion flow passage, and the internal flow passage of the experiment section is a rectangular flow passage; the air inlet section is connected with the contraction section through a first flange, the air inlet section is connected with the spray pipe section through a second flange, the spray pipe section is connected with the experiment section through a third flange, and the wind tunnel is arranged on the experiment supporting table.
The beneficial effects of the invention are as follows:
1. according to the invention, the air is injected through the circular air holes at the two ends, so that the inner flow channel of the spray pipe section forms a pneumatic throat, the ratio of the outlet area of the spray pipe section to the throat area is changed, and the Mach number change of the experimental section is realized. Compared with a spray pipe section structure adopting a flexible wall surface, the device has no complex actuating mechanism; compared with a jet pipe section structure adopting a rigid rotary wall surface, the flow field flow is uniform; and the jet speed is faster, the time response is shorter, and the time history of Mach number change is correspondingly shortened.
2. The circular wind holes are small in diameter and densely distributed, the grooves are separated by the baffle, and the number of round holes controlled by each groove is only 4; meanwhile, the three-stage confluence valves are uniformly arranged, so that the problem of uneven air flow and the problem of different times during injection/suction can be avoided.
3. The number of the pitot tubes is 1, the pressure measuring holes are arranged in the center of the experimental section, only the pressure intensity of the gas in the center of the experimental section is measured, and the number of the pitot tubes can be changed according to specific conditions so as to measure the pressure intensity in different vertical directions.
4. The invention has strong applicability, key parts can be quickly disassembled, and damaged parts can be quickly replaced by a modularized assembly process.
Drawings
FIG. 1 is a schematic diagram of the structure of the present invention;
FIG. 2 is a schematic view of the external structure of the wind tunnel of the present invention;
FIG. 3 is a schematic view of the internal structure of the wind tunnel of the present invention;
FIG. 4 is a schematic exploded view of a spray section of the present invention;
FIG. 5 is a schematic view of the structure of the arcuate plate of the present invention;
fig. 6 is an enlarged view of a portion a of fig. 5;
FIG. 7 is a schematic diagram of a second embodiment of an arcuate plate of the present invention;
FIG. 8 is a cross-sectional view of a nozzle segment of the present invention;
FIG. 9 is a schematic view of the structure of the profile on the nozzle segment of the present invention;
FIG. 10 is a schematic view of the exploded construction of the profile on the nozzle segment of the present invention;
FIG. 11 is a schematic view of the jet pumping device of the present invention;
FIG. 12 is a schematic view of the structure of the pipe of the present invention;
FIG. 13 is a schematic view of the structure of the solenoid valve of the present invention;
FIG. 14 is a schematic view of the bottom structure of the solenoid valve of the present invention;
FIG. 15 is a mating installation view of the solenoid valve and the plate of the present invention;
FIG. 16 is a schematic view of the structure of the experimental section of the present invention;
FIG. 17 is a schematic view of an exploded construction of an experimental section of the present invention;
FIG. 18 is a partial schematic view of an experimental section of the invention;
FIG. 19 is a partial schematic diagram II of an experimental section of the invention;
FIG. 20 is a schematic view of a partially exploded construction of an experimental section of the present invention;
FIG. 21 is a flow field cloud and X-Ma of a jet section without a jet suction apparatus according to the present invention;
FIG. 22 is a flow field cloud and X-Ma plot of a nozzle segment and an experimental segment in accordance with an embodiment of the present invention;
FIG. 23 is a flow field cloud and X-Ma diagram of a nozzle segment and an experimental segment in accordance with a second embodiment of the present invention;
FIG. 24 is a flow field cloud and X-Ma plot of a nozzle segment and an experimental segment in accordance with a third embodiment of the present invention;
FIG. 25 is a flow field cloud and X-Ma plot of a fourth embodiment of the present invention.
The reference numerals in the above figures are: the air intake section 1, the air intake section 2, the nozzle section 3, the left side plate 31, the right side plate 32, the upper section 33, the first section 331, the second section 332, the first fixing section 3321, the second fixing section 3322, the arc plate 3323, the cover plate 3324, the first fixing clamping plate 3325, the second fixing clamping plate 3326, the air intake hole 3327, the blind slot 3328, the circular air hole 3329, the third section 333, the lower section 34, the nozzle contraction section 35, the throat 36, the nozzle expansion section 37, the electromagnetic valve 38, the first through hole 381, the second through hole 382, the third through hole 383, the fourth through hole 384, the fifth through hole 385, the flat plate 386, the air collection chamber 39, the first-stage bus 391, the second-stage bus 392, the third-stage bus 393, the experimental section 4, the pitot tube 41, the pressure measurement hole 42, the static pressure pipe 43, the total pressure pipe 44, the pressure sensor 45, the feedback control system 46, the groove 47, the sealing plate 471, the sealing ring 472, the O-ring 48, the 49, the air compressor 51, the first pressure air tank 52, the one-way valve 53, the pressure reducing valve 54, the pressure valve 54, the second pressure tank 61, the second pressure tank 62, the third pressure tank 63, the vacuum pump 81, the third air tank flange 81, the third vacuum pump flange 81, the third air tank support flange 81, the vacuum pump 81, the third air tank flange 81, the third through hole 83.
Detailed Description
The invention is further described below with reference to the accompanying drawings:
the variable Mach number wind tunnel experimental device based on jet flow and suction structure as shown in fig. 1, 2 and 3 comprises a wind tunnel formed by sequentially connecting a contraction section 1, an air inlet section 2, a jet pipe section 3 and an experimental section 4, wherein the wind tunnel is arranged on an experimental supporting table 84. The central axes of the contraction section 1, the air inlet section 2, the spray pipe section 3 and the experiment section 4 are identical, and the internal flow passages of the contraction section 1, the air inlet section 2, the spray pipe section 3 and the experiment section 4 are sequentially communicated to form a gas flow passage of the wind tunnel. Specifically, the internal flow passage of the contraction section 1 is a trumpet-shaped flow passage with a large opening and a small outlet, the internal flow passage of the air inlet section 2 is a rectangular flow passage, the internal flow passage of the spray pipe section 3 is a contraction-expansion flow passage, and the internal flow passage of the experiment section 4 is a rectangular flow passage; the air inlet section 2 is connected with the contraction section 1 through a first flange 81, the air inlet section 2 is connected with the spray pipe section 3 through a second flange 82, and the spray pipe section 3 is connected with the experiment section 4 through a third flange 83.
Specifically, as shown in fig. 4, 8, 9 and 10, the nozzle section 3 is formed by surrounding a left side plate 31, a right side plate 32 which are symmetrically arranged, and an upper section bar 33 and a lower section bar 34 which are symmetrically arranged, wherein the end surfaces of the upper section bar 33 and the lower section bar 34 which are close to each other are convex cambered surfaces, i.e. the convex directions of the cambered surfaces point to the central axis of the nozzle section. The inner flow passage of the nozzle section 3 comprises a nozzle contraction section 35, a throat 36 and a nozzle expansion section 37 which are sequentially arranged, and the upper section 33 and the lower section 34 respectively comprise a first section 331 corresponding to the nozzle contraction section 35, a second section 332 corresponding to the throat 36 and a third section 333 corresponding to the nozzle expansion section 37. More specifically, the second profile 332 includes a first fixing portion 3321 connected to the first profile 331, a second fixing portion 3322 connected to the third profile 333, an arc plate 3323 connected to bottom ends of the first fixing portion 3321 and the second fixing portion 3322, and a cover plate 3324 connected to top portions of the first fixing portion 3321 and the second fixing portion 3322, the air collecting chamber 39 is connected to a lower plate surface of the cover plate 3324 through a first fixing clamping plate 3325 and a second fixing clamping plate 3326, and an air inlet hole 3327 communicating with the air collecting chamber 39 is formed in the cover plate 3324.
Further, as shown in fig. 5, 6 and 7, circular air holes 3329 are respectively provided on the cambered surfaces of the upper and lower profiles 33 and 34 corresponding to the throat 36, and the circular air holes 3329 are connected with a jet suction device. Specifically, a plurality of blind slots 3328 for installing electromagnetic valves 38 are distributed on an arc-shaped plate 3323 of the second section bar along a determinant, and circular air holes 3329 are formed at the bottoms of the blind slots 3328.
As shown in FIG. 11, the jet suction device comprises an air collecting cavity 39, a pipeline connected with the air collecting cavity 39 and an electromagnetic valve 38 connected with the tail end of the pipeline, a pneumatic throat can be formed in the spray pipe section 3 through on-off cutting of a hole site of the electromagnetic valve 38, and when the jet suction device is used, the Mach number of an internal flow passage of the experimental section 4 is realized by changing the ratio of the area of the throat 36 to the area of the outlet of the spray pipe expansion section 37.
Specifically, as shown in fig. 12, the pipe includes a first-stage bus bar 391, a second-stage bus bar 392 and a third-stage bus bar 393 which are sequentially arranged from top to bottom, the first-stage bus bar 391 is communicated with the air collecting cavity 39 through a hose, and the first-stage bus bar 391 and the second-stage bus bar 392 and the third-stage bus bar 393 are all connected through a hard pipe. In addition, as shown in fig. 13, 14 and 15, the electromagnetic valve 38 is a two-position three-way valve, the model is 3V320-10, the electromagnetic valve 38 includes a first through hole 381 at the top, a second through hole 382, a third through hole 383 at the bottom, a fourth through hole 384, and a fifth through hole 385, wherein: the first through hole 381 is connected to the outlet of the third stage bus bar 393 through a hard pipe. The electromagnetic valve 38 is fixed on the upper part of the blind groove 3328 through a flat plate 386, and through holes which are matched with the positions of the third through hole 383, the fourth through hole 384 and the fifth through hole 385 are arranged on the flat plate.
The solenoid valves 38 are arranged in parallel in a plurality of rows, and blind slots 3328 for installing the solenoid valves 38 are arranged on the arc-shaped plate 3323. Preferably, in the present invention, 25 rows of electromagnetic valves 38 are provided, 10 electromagnetic valves 38 are provided in each row, 25 rows of corresponding blind slots 3328 are provided, 10 blind slots 3328 are provided in each row, each row is perpendicular to the axial direction of the nozzle section 3, 4 circular air holes 3329 with diameters of 1.2mm are provided at the bottom of each blind slot 3328, and each blind slot 3328 controls 4 circular air holes 3329. In practical use, the number of the blind slots 3328 and the number of the circular air holes 3329 controlled by the blind slots 3328 can be set according to specific working conditions, and the invention only shows one setting method which is determined according to the surface area of the bottom of the spray pipe.
Any two of the rows of solenoid valves are selected for use in spraying and pumping to the throat 36, i.e. of the 25 rows of solenoid valves 38, only two of the rows are active, one for spraying and the other for pumping, the remaining 23 for regulating the position of spraying and pumping. Such as: the electromagnetic valves of the row which are originally used for jet flow are closed, and the electromagnetic valves of the different rows are opened for jet flow, so that the position of the jet flow is adjusted, and the suction is the same. When the operation is started, the first port 381, the fourth port 384 and the fifth port 385 of the array of solenoid valves for the jet flow are opened, and the second port 382 and the third port 383 are closed; the second port 382, the third port 383, and the fourth port 384 of the solenoid valve of the row for suction are opened, and the first port 381 and the fifth port 385 are closed. When the position of the jet flow or the suction circular air hole needs to be regulated, the electromagnetic valve 38 controls the opening and closing of the air ports according to the feedback signal, and the two air ports are selected at the bottom to jet flow or suction, so that the gas flow distribution is more uniform when each row of electromagnetic valves perform suction or jet flow.
Preferably, in the invention, the diameter of the circular air holes 3329 is 1.2mm, the circular air holes are small in diameter and densely distributed, and the flow is uniform when the circular air holes are sprayed to the inner flow channel of the spray pipe section 3; the diameter of each through hole on the electromagnetic valve 38 is 3.15mm, and the diameter of each through hole on the electromagnetic valve 38 is larger than the diameter of the circular air hole 3329, so that when the electromagnetic valve 38 is opened, high-pressure gas is injected into the internal flow passage of the spray pipe section 3, and the high-pressure gas tends to shrink.
As shown in fig. 16, 17, 18, 19 and 20, specifically, the experimental section 4 includes a pitot tube 41, one end of the pitot tube 41 provided with a pressure measuring hole 42 is located in an internal flow channel of the experimental section 4, a static pressure pipe 43 and a total pressure pipe 44 of the pitot tube 41 are respectively provided with a pressure sensor 45, the pressure sensor 45 is connected with a feedback control system 46, and a central axis of one end of the pitot tube 41 placed in the internal flow channel of the experimental section 4 is identical with a central axis of the internal flow channel of the experimental section 4. The pressure sensor 45 in the invention is a small pressure sensor, and an Shanghai-Tianmu NS-2 sensor is adopted, and the range of measurement is-100 kPa-35000 kPa. The static pressure pipe 43 is used for measuring the static pressure of gas, the total pressure pipe 44 is used for measuring the total pressure of gas, and the measured pressure is converted into an electric signal by the pressure sensor 45 and is input to the feedback control system 46.
The whole experimental section 4 is square, the upper surface of the experimental section 4 is provided with a groove 47 downwards, the bottom of the groove 47 is provided with a notch communicated with the flow channel inside the experimental section 4, and the notch is sealed inside and outside the experimental section 4 through a sealing plate 471 and a sealing ring 472; the pitot tube 41 is disposed through the sealing plate 471, and the pitot tube 41 forms a seal with the sealing plate 471 by the O-ring 48, so that the air tightness is ensured, and the pressure sensor 45 is connected with the feedback control system 46 by the electric wire 49.
Further, the invention also comprises an air source device, wherein the air source device comprises an air compressor 51, a first pressure air storage tank 52, a first air pipe connecting the air compressor 51 and the first pressure air storage tank 52, a second air pipe connecting the first pressure air storage tank 52 and the air collection cavity 39, a one-way valve 53 arranged on the first air pipe and a pressure reducing valve 54 arranged on the second air pipe, and the second air pipe is a hard pipeline. In the invention, the second air pipes are arranged in parallel, namely, the air from the first pressure air storage tank 52 is divided into two paths through the two second air pipes, one path is communicated with the air inlet holes 3327 on the upper section bar, and the other path is communicated with the air inlet holes 3327 on the lower section bar.
Further, the invention also comprises a vacuum device, wherein the vacuum device comprises a vacuum pump 61, a second pressure air storage tank 62, a third air pipe which is communicated with the vacuum pump 61 and the second pressure air storage tank 62, a vacuum valve 63 arranged on the third air pipe, and a fourth air pipe which is communicated with the second pressure air storage tank 62 and the internal flow passage of the spray pipe section 3.
Further, the invention also comprises a gas tank 7, the gas tank 7 is communicated with the contraction section 1 through a fifth gas pipe, and a one-way ball valve 71 is arranged on the fifth gas pipe.
The working principle and working process of the invention are as follows:
the invention relates to an air inlet section 2 and a contraction section 1 which are used for providing incoming flow for experiments, a jet pipe section 3 is provided with a jet flow suction device which enables the jet pipe to form a pneumatic throat channel so as to realize Mach number change, a pressure sensor and a feedback control system are arranged in the experiment section, the static pressure and the total pressure of air flow are measured through a pitot tube, the Mach number of the air flow in the experiment section is calculated, and the Mach number is fed back to a solenoid valve control unit so as to control the position and working pressure of the jet flow/suction port.
Before the experiment, the air compressor 51 generates high-pressure gas, the high-pressure gas enters the first pressure gas storage tank 52 through the one-way valve 53, the vacuum pump 61 generates vacuum gas, and the vacuum gas enters the second pressure gas storage tank 62 through the vacuum valve 63; during experiments, the one-way ball valve 71 is opened, the air flow input by the air tank 7 enters the contraction section 1, mach number in the experiment section 4 reaches a stable value through the air inlet section 2 and the spray pipe section 3, the static pressure and the total pressure are measured through the pitot tube 41, the measured pressure is converted into an electric signal through the pressure sensor 45, the electric signal enters the feedback control system 46, and the feedback control system 46 converts the pressure signal into a Mach number signal according to a forward shock wave formed in front of the pitot tube 41, and the Mach number signal is fed back to a control unit of the electromagnetic valve 38 according to a forward-backward airflow relation of the laser, so that the electromagnetic valve 38 is controlled to be opened; at the same time, the second pressure air storage tank 62 is opened, so that the internal cavity of the spray pipe section 3 is vacuumized; then the first pressure air storage tank 52 is opened, high-pressure air enters the air collection cavity 39 from the second air pipe through the pressure reducing valve 54, the high-pressure air in the air collection cavity 39 is sprayed into the internal flow passage of the spray pipe section 3 after passing through the three-stage bus bar and the electromagnetic valve 38, at the moment, the row of electromagnetic valves 38 for spraying jet flow sprays the high-pressure air into the internal flow passage of the spray pipe section 3, and the row of electromagnetic valves 38 for sucking sucks the air outwards from the internal flow passage of the spray pipe section 3 to form a pneumatic throat, so that the ratio of the outlet area of the spray pipe section 3 to the throat area is changed, and the Mach number is changed; when the mach number reaches a stable value, the static pressure and the total pressure are measured through the pitot tube 41, the static pressure and the total pressure are converted into electric signals through the pressure sensor 45, the electric signals are converted into mach number signals through the feedback control system 46 and fed back to the control unit of the electromagnetic valve, the change of the injection position and the working pressure of the regulating electromagnetic valve 38 are controlled, and the operation is repeatedly continued.
The relation between the front and back air flows of the laser in the principle is as follows:
wherein: wherein p is t Is static pressure, p 1 Is the total voltage after forward shock wave, ma 1 Is the Mach number after forward shock wave, p ∞ Is the total wave front pressure of normal shock wave, ma ∞ And the wave front Mach number of the normal shock wave is obtained, gamma is the absolute pressure coefficient, and 1.4 is taken.
As shown in fig. 21, when the jet suction device is not used in the present invention, the mach number of the whole flow field is changed as shown in fig. 21 (a), the mach number cloud around the throat is shown in fig. 21 (b), the mach number of the experimental section is shown in fig. 21 (c), the mach number change curve is shown in fig. 21 (d), and the mach number of the main flow area is 2.8.
Embodiment one:
the air compressor 51 generates high-pressure gas, the high-pressure gas enters the first pressure gas storage tank 52 through the one-way valve 53, the vacuum pump 61 generates vacuum gas, and the vacuum gas enters the second pressure gas storage tank 62 through the vacuum valve 63; during experiments, the one-way ball valve 71 is opened, the air tank 7 inputs air flow of 1 atmosphere (atm for short) into the contraction section 1, mach number in the experiment section 4 reaches 2.8Ma through the air inlet section 2 and the spray pipe section 3, the static pressure and the total pressure are measured through the pitot tube 41, the measured pressure is converted into electric signals through the pressure sensor 45, the electric signals enter the feedback control system 46, the feedback control system 46 converts the pressure signals into Mach number signals according to a front-back air flow relation of the laser and feeds back the Mach number signals to the control unit of the electromagnetic valve 38, and the electromagnetic valve 38 is controlled to be opened; at the same time, the second pressure air storage tank 62 is opened, so that the internal cavity of the spray pipe section 3 is vacuumized; then the first pressure air storage tank 52 is opened, high-pressure air enters the air collection cavity 39 from the second air pipe through the pressure reducing valve 54, the high-pressure air in the air collection cavity 39 is sprayed into the internal flow passage of the spray pipe section 3 after passing through the three-stage bus and the electromagnetic valve 38, at the moment, the row of electromagnetic valves 38 for spraying jet flow sprays the high-pressure air into the internal flow passage of the spray pipe section 3, the sprayed high-pressure air is absolute pressure of 1.8atm, the row of electromagnetic valves 38 for sucking sucks air from the internal flow passage of the spray pipe section 3, the pressure of the sucked air is absolute pressure of 0.1atm, a pneumatic throat is formed, the ratio of the outlet area of the spray pipe section 3 to the throat area is changed, and the Mach number is changed; when the mach number reaches 3.5Ma, the magnitudes of the static pressure and the total pressure are measured through the pitot tube 41, and converted into electric signals by the pressure sensor 45, the electric signals are converted into mach number signals by the feedback control system 46 and fed back to the control unit of the electromagnetic valve, the change of the injection position and the working pressure of the regulating electromagnetic valve 38 are controlled, and the above operation is repeatedly continued.
As shown in fig. 22, the overall flow field mach number variation is now shown in fig. 22 (a); the Mach number cloud diagram near the throat is shown in fig. 22 (b), double arrows in the diagram respectively indicate the formed pneumatic throat position and the original throat position, and it can be seen that the embodiment realizes the forward movement of the throat and changes the area ratio; the experimental section mach number is shown in fig. 22 (c), and the mach number variation range is larger than that in the case of no jet/suction, and the mach number variation curve is shown in fig. 22 (d), and the mach number in the main stream area is 3.5.
Embodiment two:
as shown in fig. 23, the operation of example 1 was repeated by changing the pressure of the air flow sucked by the solenoid valve to 0.4atm absolute pressure on the basis of the first example. At this time, the entire flow field Mach number variation is shown in FIG. 23 (a); the Mach number cloud diagram near the throat is shown in fig. 23 (b), two double arrows in the diagram respectively indicate the formed pneumatic throat position and the original throat position, and it can be seen that the embodiment realizes the forward movement of the throat and changes the area ratio; the experimental section mach number is shown in fig. 23 (c), and the mach number variation range is larger than that in the case of no jet/suction, and the mach number variation curve is shown in fig. 23 (d), and the mach number in the main stream area is 3.4.
Embodiment III:
as shown in fig. 24, on the basis of the first embodiment, the position of the circular wind hole for suction (before adjustment, at x-axis-0.004 m, see fig. 22 (b), after adjustment, at x-axis-0.005 m) was adjusted), and the operation of the first embodiment was repeated. At this time, the entire flow field mach number variation is shown in fig. 24 (a); the Mach number cloud diagram near the throat is shown in fig. 24 (b), and two double arrows in the diagram respectively represent the formed pneumatic throat position and the adjusted suction circular hole position, so that the embodiment realizes the forward movement of the throat and changes the area ratio; the mach number of the experimental section is shown in fig. 24 (c), and it can be seen that the mach number of the suction port is reduced in the opposite direction of the flow direction, and the mach number variation curve is shown in fig. 24 (d), and the mach number of the main stream area is 3.4, which is reduced by 0.1 compared with the mach number of the main stream area before the adjustment.
Embodiment four:
as shown in fig. 25, on the basis of the first embodiment, the position of the circular wind hole for jet flow (before adjustment, at x-axis-0.01 m, see fig. 22 (b), after adjustment, at x-axis-0.016 m) was adjusted, and the operation of the first embodiment was repeated. At this time, the entire flow field Mach number variation is shown in FIG. 25 (a); the Mach number cloud diagram near the throat is shown in fig. 25 (b), and two double arrows in the diagram respectively indicate the formed pneumatic throat position and the regulated jet flow circular hole position, so that the embodiment realizes the forward movement of the throat and changes the area ratio; the mach number of the experimental section is shown in fig. 25 (c), it can be seen that the jet orifice is adjusted in the opposite direction of the flow direction, the mach number is increased, the mach number variation curve is shown in fig. 25 (d), the mach number of the main stream area is 3.7, and the mach number of the main stream area is increased by 0.2 compared with the mach number of the main stream area before adjustment.
The above examples are only illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention, and various modifications and improvements made by those skilled in the art to the technical solution of the present invention should fall within the scope of protection defined by the claims of the present invention without departing from the spirit of the present invention.
Claims (8)
1. The utility model provides a variable Mach number wind tunnel experiment device based on jet and suction structure which characterized in that: the device comprises a wind tunnel formed by sequentially connecting a contraction section (1), an air inlet section (2), a spray pipe section (3) and an experimental section (4), wherein central axes of the contraction section (1), the air inlet section (2), the spray pipe section (3) and the experimental section (4) are identical, and internal flow passages of the contraction section (1), the air inlet section (2), the spray pipe section (3) and the experimental section (4) are sequentially communicated to form a gas flow passage of the wind tunnel; the jet pipe section (3) is formed by surrounding a left side plate (31), a right side plate (32) and an upper section (33) and a lower section (34) which are symmetrically arranged, the end surfaces of the upper section (33) and the lower section (34) which are close to each other are outwards convex cambered surfaces, the inner flow passage of the jet pipe section (3) comprises a jet pipe contraction section (35), a throat (36) and a jet pipe expansion section (37) which are sequentially arranged, circular air holes (3329) which are arranged in a determinant manner are respectively arranged on the cambered surfaces of the upper section (33) and the lower section (34) corresponding to the throat (36), the circular air holes (3329) are connected with a jet flow suction device, the jet flow suction device comprises an air collecting cavity (39), a pipeline connected with the air collecting cavity (39) and an electromagnetic valve (38) connected with the tail end of the pipeline, and a pneumatic throat can be formed in the jet pipe section (3) through on-off cutting of the electromagnetic valve (38), and the ratio of the area of the throat (36) to the area of the outlet of the jet pipe expansion section (37) is changed, so that the number of the inner flow passage of the experiment section (4) is changed;
the air source device comprises an air compressor (51), a first pressure air storage tank (52), a first air pipe connected with the air compressor (51) and the first pressure air storage tank (52), a second air pipe connected with the first pressure air storage tank (52) and the air collection cavity (39), a one-way valve (53) arranged on the first air pipe and a pressure reducing valve (54) arranged on the second air pipe, wherein the second air pipe is a hard pipeline;
the vacuum device comprises a vacuum pump (61), a second pressure air storage tank (62), a third air pipe communicated with the vacuum pump (61) and the second pressure air storage tank (62), a vacuum valve (63) arranged on the third air pipe and a fourth air pipe communicated with the second pressure air storage tank (62) and an internal flow channel of the spray pipe section (3);
the air cylinder (7) is communicated with the contraction section (1) through a fifth air pipe, and a one-way ball valve (71) is arranged on the fifth air pipe.
2. The jet and suction structure based variable mach number wind tunnel experimental device of claim 1, wherein: the experimental section (4) comprises a pitot tube (41), one end of the pitot tube (41) provided with a pressure measuring hole (42) is located in an internal flow channel of the experimental section (4), a static pressure pipe (43) and a total pressure pipe (44) of the pitot tube (41) are respectively provided with a pressure sensor (45), and the pressure sensor (45) is connected with a feedback control system (46).
3. The jet and suction structure based variable mach number wind tunnel experimental device of claim 2, wherein: the experimental section (4) is square as a whole, a groove (47) is formed in the upper surface of the experimental section (4) downwards, a notch communicated with an internal flow channel of the experimental section (4) is formed in the bottom of the groove (47), and the notch is sealed inside and outside the experimental section (4) through a sealing plate (471) and a sealing ring (472); the pitot tube (41) penetrates through the sealing plate (471), the pitot tube (41) and the sealing plate (471) form a seal through the O-shaped ring (48), and the pressure sensor (45) is connected with the feedback control system (46) through the electric wire (49).
4. The jet and suction structure based variable mach number wind tunnel experimental device of claim 1, wherein: the upper section bar (33) and the lower section bar (34) respectively comprise a first section bar (331) corresponding to the spray pipe contraction section (35), a second section bar (332) corresponding to the throat (36) and a third section bar (333) corresponding to the spray pipe expansion section (37), the second section bar (332) comprises a first fixed part (3321) connected with the first section bar (331), a second fixed part (3322) connected with the third section bar (333), an arc-shaped plate (3323) connected at the bottom ends of the first fixed part (3321) and the second fixed part (3322) and a cover plate (3324) connected at the tops of the first fixed part (3321) and the second fixed part (3322), the air collecting cavity (39) is connected to the lower plate surface of the cover plate (3324) through a first fixed clamping plate (3325) and a second fixed clamping plate (3326), and an air inlet hole (3327) communicated with the inside of the air collecting cavity (39) is formed in the cover plate (3324).
5. The jet and suction structure based variable mach number wind tunnel experimental device of claim 1, wherein: the pipeline include from last first order busbar (391), second order busbar (392) and tertiary busbar (393) that arrange down in proper order, first order busbar (391) pass through hose and gas collection chamber (39) intercommunication, first order busbar (391) and second order busbar (392) between, all be connected through the hard tube between second order busbar (392) and the tertiary busbar (393).
6. The jet and suction structure based variable mach number wind tunnel experimental device of claim 1, wherein: the electromagnetic valve (38) is a two-position three-way valve, the electromagnetic valve (38) comprises a first through hole (381) at the top, a second through hole (382), a third through hole (383) at the bottom, a fourth through hole (384) and a fifth through hole (385), wherein: the first through hole (381) is connected with the outlet of the third-stage busbar (393) through a hard pipe, and the diameter of each through hole on the electromagnetic valve (38) is larger than the diameter of the circular air hole (3329).
7. The jet and suction structure based variable mach number wind tunnel experimental device of claim 4, wherein: the electromagnetic valves (38) are arranged in parallel, blind grooves (3328) for installing the electromagnetic valves (38) are formed in the arc-shaped plates (3323), any two rows of electromagnetic valves are selected for the multiple rows of electromagnetic valves to jet and suck towards the throat (36), and the circular air holes (3329) are formed in the bottoms of the blind grooves (3328).
8. The jet and suction structure based variable mach number wind tunnel experimental device of claim 1, wherein: the internal flow passage of the contraction section (1) is a horn-shaped flow passage with a large opening and a small outlet, the internal flow passage of the air inlet section (2) is a rectangular flow passage, the internal flow passage of the spray pipe section (3) is a contraction-expansion flow passage, and the internal flow passage of the experiment section (4) is a rectangular flow passage; the air inlet section (2) is connected with the contraction section (1) through the first flange (81), the air inlet section (2) is connected with the spray pipe section (3) through the second flange (82), the spray pipe section (3) is connected with the experiment section (4) through the third flange (83), and the wind tunnel is arranged on the experiment supporting table (84).
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117740321A (en) * | 2024-02-20 | 2024-03-22 | 中国科学技术大学 | Shock wave experiment system |
| CN117740321B (en) * | 2024-02-20 | 2024-05-17 | 中国科学技术大学 | Shock wave experiment system |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117740321A (en) * | 2024-02-20 | 2024-03-22 | 中国科学技术大学 | Shock wave experiment system |
| CN117740321B (en) * | 2024-02-20 | 2024-05-17 | 中国科学技术大学 | Shock wave experiment system |
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