Temperature-controllable open-type low-Reynolds-number intelligent wind tunnel

Abstract

The invention discloses a temperature-controllable open-type low-Reynolds-number intelligent wind tunnel, and relates to the field of cascade wind tunnel tests applied to the turbomachinery field. The problems that an existing low-Reynolds-number wind tunnel test bed can only conduct simulation at the normal temperature, and a heated low-Reynolds-number test cannot be conducted are solved. An air inlet device (A-11) is connected with an air inlet heater (A-14) through a main air inlet adjusting valve (A-12) and an auxiliary air inlet adjusting valve (A-13) which are arranged in parallel, air flow sucked by the air inlet device (A-11) from the atmosphere is heated by the air inlet heater (A-14), then enters a first expansion joint (A-15) and is connected with a wind tunnel body (B), and a secondary flow system (C) is connected with an experiment module (B-23) in the wind tunnel body (B). And the exhaust system (D) is connected with the exhaust side of the experiment module (B-23). The device and the method are used for aerothermal performance experiments of key components of turbomachinery and high-altitude aircraft simulation tests in a low Reynolds number environment.

Description

Technical Field

[0001] The present invention relates to an aerodynamic performance test technology for key impeller machinery components of high-altitude aircraft, aeroengines and gas turbines, and in particular to a temperature-controllable open low-Reynolds number intelligent wind tunnel. Background Art

[0002] When an aircraft is operating at high altitude (above 10,000 meters), the density of the atmosphere is greatly reduced compared to that on the ground, so the key aerodynamic parameter that affects the flow, the Reynolds number, becomes very low, which will bring about the problem of low Reynolds number flow. This is a problem that must be solved in the design of high-altitude aircraft and aircraft engines. At the same time, the demand for high-altitude aircraft and aircraft engines at home and abroad is on the rise; the lack of a low Reynolds number database for engines restricts engine development; and the number of test benches in China that have low Reynolds number wind tunnels that simulate high altitudes is limited, resulting in high test costs and cannot meet the large demands of various research and development units. A survey of domestic low Reynolds number test benches found that domestic low Reynolds number wind tunnel test benches only simulate at room temperature and do not have the ability to conduct heated low Reynolds number tests.

[0003] For example: the authorization announcement number is: CN108254130B, the patent name is continuous high temperature sealing performance test wind tunnel device, including air compressor, gas cylinder, normal temperature pressure gauge, stop valve a, pressure reducing valve, air flow meter a, pipeline air heater, stop valve b, high temperature thermometer a, high temperature pressure gauge, test section, air flow meter b, high temperature thermometer b, the device is pressurized by the air compressor and stored in the gas cylinder, then the pressure is adjusted by the pressure reducing valve, then heated by the pipeline air heater, and finally passed through the test section, the test piece is fixed in the specific groove of the test section, and the distance between the upper cover plate and the base of the test section is changed by replacing the adjustment gaskets of different sizes to change the compression of the test piece, and the sealing and thermal insulation parameters of the test piece under different compression, different pressure difference conditions and different temperatures can be obtained by installing high temperature thermometer a, high temperature pressure gauge, air flow meter b, and high temperature thermometer b before and after the sealing device. Although it can realize wind tunnel test, it is a test for sealing performance. It is not applicable to blade performance tests of aircraft engines under low Reynolds number conditions and at different temperatures.

[0004] Among them, when aircraft engines operate under low Reynolds number conditions, the flow in the blade grooves is often in a laminar or laminar-turbulent mixed flow state, which can easily cause flow separation on the blade suction surface. In severe cases, it can cause flow blockage, which in turn affects the matching between the compressor and turbine blade rows, resulting in reduced efficiency and performance of engine components, and ultimately causing a decrease in engine thrust, increased fuel consumption, and poor working stability and reliability, which has a huge impact on the completion of flight missions.

[0005] In summary, the existing low Reynolds number wind tunnel test bench can only perform simulations at room temperature, and there is a problem that low Reynolds number tests cannot be performed with heating. Summary of the invention

[0006] The purpose of the present invention is to solve the problem that the existing low Reynolds number wind tunnel test bench can only simulate at room temperature and cannot perform low Reynolds number tests with heating, and further provide a temperature-controllable open low Reynolds number intelligent wind tunnel.

[0007] The technical solution of the present invention is:

[0008] A temperature-controllable open low-Reynolds number intelligent wind tunnel comprises an air intake system, a wind tunnel body, a secondary flow system and an exhaust system. The air intake system comprises an air intake device, a main air intake regulating valve, an auxiliary air intake regulating valve, an air intake heater and a first expansion joint. The air intake device is connected to the air intake heater through the main air intake regulating valve and the auxiliary air intake regulating valve arranged in parallel, and the airflow drawn from the atmosphere by the air intake device enters the first expansion joint after being heated by the air intake heater; the first expansion joint is connected to the wind tunnel body, the secondary flow system is connected to an experimental cabin in the wind tunnel body, and the exhaust system is connected to the exhaust side of the experimental cabin.

[0009] Furthermore, the air intake system also includes a guide device and an air intake duct, which are installed between the air intake device and the main air intake regulating valve; the guide device includes a conical shell and a metal mesh, the conical shell is connected to the air intake duct in sequence, and the metal mesh is installed at the large end of the conical shell, wherein the metal mesh includes an outer metal mesh and an inner metal mesh, and the outer metal mesh and the inner metal mesh are installed in sequence at the large end of the conical shell.

[0010] Furthermore, the wind tunnel body includes a diffuser section, a stabilizer section and a test chamber, which are connected sequentially from left to right, wherein the test chamber includes a convergence section, a nozzle section and a test chamber, which are connected sequentially from left to right.

[0011] Furthermore, the test section includes an inner shell, an outer shell, a positioning block assembly, a plurality of connecting limit members, an inner disc, an outer disc, an angle of attack adjustment drive, an upper baffle assembly and a lower baffle assembly; the inner shell and the outer shell are connected by a plurality of connecting limit members, the positioning block assembly is installed on the air intake side of the inner shell and the outer shell, one end of the upper baffle assembly is rotatably connected to the positioning block assembly, and is used to clamp on the blade of the upper part of the blade to be tested, and the lower baffle assembly is slidably matched with the side of the positioning block assembly and moves up and down, and is used to resist the lower part of the blade to be tested; the inner disc and the outer disc are rotatably installed on the inner shell and the outer shell respectively, and rectangular holes are respectively opened on the inner disc and the outer disc, wherein the blade to be tested is installed in the rectangular hole, scales are engraved on the outer side of the inner shell, and the rotation angles of the inner disc and the outer disc are measured, the angle of attack adjustment drive is installed on the outer side of the inner disc, and the angle of attack adjustment drive drives the inner disc and the outer disc to rotate simultaneously, so as to realize the change of the angle of attack of the blade to be tested.

[0012] Preferably, the positioning block assembly comprises an upper positioning block and a lower positioning block, the upper positioning block and the lower positioning block are fixedly mounted on the air inlet side of the inner shell and the outer shell, and the upper positioning block and the lower positioning block are arranged in parallel.

[0013] Preferably, the end of the lower positioning block is provided with a 45° bevel.

[0014] Preferably, the connection limiter comprises a distance sleeve and a bolt. The bolt passes through the outer shell, is inserted into the distance sleeve between the inner shell and the outer shell, extends out of the inner shell, and is then installed on the inner shell through a nut.

[0015] Furthermore, the secondary flow system includes an air compressor, a dryer, a gas tank, a first switch valve, a first regulating valve and a flow meter, and the air compressor, the dryer, the gas tank, the first switch valve, the first regulating valve and the flow meter are connected in sequence.

[0016] Furthermore, it also includes an electrical system, a test system, a video monitoring system, auxiliary process equipment and a cooling water system. The electrical system, the test system, the video monitoring system and the auxiliary process equipment are electrically connected to the intake system, the wind tunnel body and the secondary flow system respectively, and the cooling water system is connected to the exhaust system.

[0017] Furthermore, the exhaust system includes a second expansion joint, a heat exchanger, multiple second switch valves and multiple vacuum pumps. The multiple second switch valves are connected in parallel, each second switch valve is connected to a vacuum pump, and the second expansion joint and the heat exchanger are connected to the multiple second switch valves arranged in parallel.

[0018] Compared with the prior art, the present invention has the following effects:

[0019] 1. Compared with the existing low Reynolds number wind tunnel, the suction unit (referring to the vacuum pump D-44) of the present invention adopts variable frequency control, and the main and auxiliary regulating valves at the inlet of the intake system A can effectively adjust the low Reynolds number range; the intake heater A-14 in the intake system A can control the inlet air flow temperature to meet the test requirements; at the same time, according to the test requirements, the nozzle section and the test section in the test cabin can be installed or removed, and then the fan, compressor, turbine blade performance test or the three-dimensional high-altitude aircraft modeling test can be carried out. In summary, a temperature-controllable open low-Reynolds number intelligent wind tunnel can test high-altitude aircraft, aircraft engine fans, compressors and turbine blades respectively, which can meet the needs of temperature control and measurement within a relatively low Reynolds number range.

[0020] 2 The wind tunnel of the present invention can provide a test environment for high-altitude aircraft and aircraft engines under low Reynolds number conditions, and the inlet temperature of the wind tunnel is controllable. Among them, blade profile research is the basic and key work in the development of aircraft engines. In order to improve the overall performance of the engine, the blade profile optimization and improvement of components such as fans, compressors, and turbines is a long-term, iterative process. Plane blade cascade tests are relatively conventional and are carried out with a higher frequency. The test bench can meet the test and testing needs of high-altitude aircraft and aircraft engines under low Reynolds number conditions. Specific tests that can be carried out include: low Reynolds number blade cascade performance test, low Reynolds number blade cascade cooling effect test, low Reynolds number flow display test, digital twin technology for blade cascade test, and modeling test of high-altitude aircraft.

[0021] 3. The test section B-26 of the present invention is to install the blade to be tested on the rectangular holes of the inner disk and the outer disk, and fix it on the rectangular holes of the inner disk and the outer disk under the action of multiple bolts. When the blade to be tested is installed, the upper nut screw pair first drives the upper contraction wall plate to be lifted through the upper lifting connection piece. After the blade to be tested is fixed, the end of the upper contraction wall plate is placed on the top of the uppermost blade, and the lower contraction wall plate is pushed by the lower nut screw pair to move upward along the inclined surface of the lower positioning block to drag the lower end of the blade to be tested. When it is necessary to adjust the angle of attack for the blade test, turn the handle, after the steering assembly turns, drive the worm to rotate, the worm drives the worm wheel to rotate, and the worm wheel drives the inner disk and the outer disk to rotate at the same time. Since the blade to be tested is installed on the inner disk and the outer disk, the angle of attack of the blade to be tested is changed by rotating the worm wheel and the worm under the condition that the direction of the inlet airflow remains unchanged, and the blade wind tunnel test of various angles of attack can be realized.

[0022] 4. The upper and lower contraction panels of the present invention can be rotated and moved, so they can be applied to wind tunnel tests of blade cascades of different models. At the same time, for wind tunnel tests of turbine and compressor blade cascades of different designs, only the test blades themselves need to be replaced, and other component structures can still be installed and used, thus saving the test cost to the greatest extent.

[0023] 5. The present invention adopts manually controlled worm gear to realize effective and high-precision adjustment of the test blade angle, avoiding the failure and adverse problems caused by the use of electric control structure in high temperature environment.

[0024] 6. The test section disc structure of the present invention can change the rotation angle of the adjustable blade cascade. During the blade cascade test, the monitoring and adjustment functions of the blade angle of attack of the test blade cascade can be realized, thereby optimizing the adjustable rotation angle blade cascade test process. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0026] Figure 2 It is a schematic diagram of the structure of the guide device A-16 and the intake duct A-17.

[0027] Figure 3 It is a schematic diagram of the structure of the stable segment B-22.

[0028] Figure 4 This is an axonometric view of test section B-26.

[0029] Figure 5 yes Figure 4 Schematic diagram of the structure after removing the four-degree-of-freedom displacement mechanism 23.

[0030] Figure 6 yes Figure 5 Exploded diagram.

[0031] Figure 7 yes Figure 4 Bottom view of .

[0032] Figure 8 It is a structural schematic diagram of the air flow channel.

[0033] Fig. 9 It is a schematic diagram of the overall framework of the video surveillance system G.

[0034] Fig.10 This is the relationship between the inlet Mach number and mass flow rate of the test piece under the throttling and heating conditions at the blade inlet (pressure 10000Pa, temperature 800K).

[0035] Fig.11This is the relationship between the inlet Mach number and mass flow rate of the test piece under the throttling and heating conditions at the blade inlet (pressure 10000Pa, temperature 800K).

[0036] in:

[0037] A, air intake system, A-11, air intake device, A-12, main air intake regulating valve, A-13, auxiliary air intake regulating valve, A-14, air intake heater, A-15, first expansion joint, A-16, flow guide device, A-17, air intake pipe;

[0038] B, wind tunnel body, B-21, diffuser section, B-22, stabilization section, B-23, test chamber, B-24, contraction section, B-25, nozzle section, B-26, test section;

[0039] C, secondary flow system, C-31, air compressor, C-32, dryer, C-33, gas tank, C-34, first switch valve, C-35, first regulating valve, C-36, flow meter,

[0040] D, exhaust system, D-41, second expansion joint, D-42, heat exchanger, D-43, second switch valve, D-44, vacuum pump,

[0041] 1. Inner shell, 2. Outer shell, 3. Inner disc, 4. Outer disc, 5. Rectangular hole, 6. Upper positioning block, 7. Lower positioning block, 8. Distance sleeve, 9. Bolt, 10. Worm gear, 11. Worm, 12. Handle, 13. Steering assembly, 14. Worm mounting seat, 15. Upper retractable wall plate, 16. Rotating connecting piece, 17. Upper lifting connecting piece, 18. Upper nut screw pair, 19. Lower retractable wall plate, 20. Lifting support, 21. Lower lifting connecting piece, 22. Lower nut screw pair, 23. Four-degree-of-freedom displacement mechanism, 20-1. Bracket, 20-2. Slide rail, 20-3. Sliding block;

[0042] E. Electrical system, F. Test system, G. Video surveillance system, H. Auxiliary process equipment, I. Cooling water system,. DETAILED DESCRIPTION

[0043] Specific implementation method 1: Combination Figures 1 to 11The present embodiment is described. The present embodiment includes an air intake system A, a wind tunnel body B, a secondary flow system C and an exhaust system D. The air intake system A includes an air intake device A-11, a main air intake regulating valve A-12, an auxiliary air intake regulating valve A-13, an air intake heater A-14 and a first expansion joint A-15. The air intake device A-11 is connected to the air intake heater A-14 through the main air intake regulating valve A-12 and the auxiliary air intake regulating valve A-13 arranged in parallel, and the airflow drawn from the atmosphere by the air intake device A-11 is heated by the air intake heater A-14 and then enters the first expansion joint A-15; the first expansion joint A-15 is connected to the wind tunnel body B, the secondary flow system C is connected to the experimental cabin B-23 in the wind tunnel body B, and the exhaust system D is connected to the exhaust side of the experimental cabin B-23.

[0044] This embodiment adopts an open wind tunnel system, which works in a suction mode under the suction action of the exhaust unit (referring to the vacuum pump D-44) (the exhaust unit adopts variable frequency control, which can reduce the energy consumption in the test project and improve the efficiency of test parameter adjustment); its inlet condition is the atmospheric environment, and the air flow at the outlet of the test section is connected to the exhaust unit (referring to the vacuum pump D-44) after passing through the heat exchanger, and finally discharged into the atmosphere; after the test is started, the exhaust unit (referring to the vacuum pump D-44) forms a low back pressure at the outlet of the test section to meet the low Reynolds number requirement, and the air passes through the intake pipe and is heated by the heater (can be Oil, electric heating, the highest temperature is heated to 800K), the main and auxiliary pressure regulating valves are adjusted, the diffuser section enters the pressure regulating box for rectification, and then enters the binary nozzle through the convergent section (when simulating high-altitude aircraft, the nozzle section and the test section in the test chamber can be removed, and then the high-altitude aircraft can be tested under the low-altitude Reynolds number state in three-dimensional space), forming a certain speed of airflow into the test section to carry out a blowing test on the model test piece; according to the needs, the cooling effect test research of the relevant secondary flow can be carried out to simulate the blade cooling; among them, under the heating and throttling state, when the Mach number is 0.7, the maximum Reynolds number is 1.6953×10 4 .

[0045] like Figure 1 As shown, by jointly controlling the vacuum pump in the exhaust system, the unit is frequency-controlled to change the speed of the vacuum pump to adjust the power of the unit, and at the same time, the main air intake regulating valve and the auxiliary air intake regulating valve are adjusted to achieve the control of the Mach number and Reynolds number at the cascade inlet. When the vacuum exhaust unit achieves the Mach number at the cascade inlet at a specific speed, the pressure is regulated by controlling the test piece inlet valve, and then the inlet Reynolds number is controlled. Because the unit is jointly sucked, the pressure at the fan outlet must be higher than the atmospheric pressure to achieve normal exhaust of the unit.

[0046] Specific implementation method 2: Combination Figure 1To illustrate this embodiment, the air intake system A of this embodiment further includes a flow guide device A-16 and an air intake duct A-17, and the flow guide device A-16 and the air intake duct A-17 are installed between the air intake device A-11 and the main air intake regulating valve A-12;

[0047] The guide device A-6 includes a conical shell and a metal mesh. The conical shell is connected in sequence with the air intake pipe A-17. The metal mesh is installed at the large end of the conical shell. The metal mesh includes an outer metal mesh and an inner metal mesh. The outer metal mesh and the inner metal mesh are installed in sequence at the large end of the conical shell.

[0048] The present invention adopts an open cycle, that is, the airflow of the intake system comes from the atmospheric environment, flows into the guide device and the intake duct (such as Figure 2 As shown in the figure, the guide device is in a cone shape, and two layers of metal mesh are added at its entrance, one coarse mesh and one fine mesh. Following the direction of the airflow, the airflow first passes through the fine mesh and then the coarse mesh. The coarse mesh is used to provide support and prevent birds and other larger objects from entering. The fine mesh is used to filter out some dust and impurities to protect the heater, test piece, heat exchanger and vacuum pump unit. Then, after being adjusted by the main regulating valve and the auxiliary regulating valve, the airflow enters the heater for heating. The heater can use oil or electricity to heat the airflow to reach the temperature required by the test conditions (taking aviation kerosene heating as an example, its calorific value is 43.5×106J / kg, assuming that the maximum flow rate of the intake system is 5.5kg / s, the airflow temperature from the atmosphere is 288.15K, assuming that the combustion efficiency is 0.9, and the isentropic index of the fuel gas is 1.33, the heated airflow reaches 800K, and the maximum supply of the fuel system is 323kg / h); the heated fluid enters the wind tunnel body 2 through the expansion joint 15.

[0049] Specific implementation method three: Combination Figure 1 To illustrate this embodiment, the wind tunnel body B of this embodiment includes a diffusion section B-21, a stabilization section B-22 and a test chamber B-23, which are connected in sequence from left to right, wherein the test chamber B-23 includes a contraction section B-24, a nozzle section B-25 and a test section B-26, which are connected in sequence from left to right.

[0050] The airflow entering the wind tunnel body of the present invention first enters the diffuser section, and the outlet of the diffuser section is the stabilization section. The structure of the stabilization section is as follows: Figure 3 As shown in the figure, the length of the stabilization section is usually 2 to 3 times of the direct section, which is composed of a shell, a perforated plate, a damping mesh and a honeycomb. The purpose of the stabilization section is to make the airflow entering the nozzle uniform and reduce the turbulence to ensure the quality of the airflow at the inlet of the convergent section and the nozzle section, and then ensure the quality of the airflow field at the nozzle outlet entering the test section.

[0051] The airflow out of the stable section enters the experimental cabin, which includes a contraction section, a nozzle section and a test section. The test cabin provides stable low pressure and sealing conditions for its test section; the airflow entering the experimental cabin first reaches the contraction section, where the function of the contraction section is to accelerate the airflow and at the same time make it reach the speed required for the test, and should meet the following requirements: when the airflow flows along the convergence section, there is no separation on the cave wall; the airflow at the outlet of the convergence section is required to be uniform, straight and stable; the airflow out of the contraction section enters the nozzle section, and the function of the nozzle is to ensure that the test section entrance obtains a uniform airflow of the designed Mach number to ensure the quality of the test flow field; finally, the airflow enters the test section.

[0052] Specific implementation method four: Combination Figures 4 to 8 The present embodiment is described, and the present embodiment comprises an inner shell 1, an outer shell 2, a positioning block assembly, a plurality of connection limiters, an inner disc 3, an outer disc 4, an angle measuring ruler, an attack angle adjustment driving member, an upper baffle assembly and a lower baffle assembly; the inner shell 1 and the outer shell 2 are connected by a plurality of connection limiters, the positioning block assembly is installed on the air inlet side of the inner shell 1 and the outer shell 2, one end of the upper baffle assembly is rotatably connected to the positioning block assembly to be clamped on the upper part of the cascade to be tested, and the lower baffle assembly is slidably matched with the side of the positioning block assembly. The combined lifting movement is used to support the lower part of the blade test piece; the inner disk 3 and the outer disk 4 are rotatably mounted on the inner shell 1 and the outer shell 2 respectively, and rectangular holes 5 are respectively opened on the inner disk 3 and the outer disk 4, wherein the blade test piece is installed in the rectangular hole 5, the angle measuring ruler is installed on the outer side of the inner shell 1 to measure the rotation angle of the inner disk 3 and the outer disk 4, the attack angle adjustment drive is installed on the outer side of the inner disk 3, and the attack angle adjustment drive drives the inner disk 3 and the outer disk 4 to rotate simultaneously, so as to realize the change of the attack angle of the blade test piece.

[0053] The test section of this embodiment is the core part of the wind tunnel, and its function is to install and fix the test piece. The blade test section must also have the function of adjusting the blade inlet angle of attack. The adjustment range of the angle between the test piece's frontal line and the incoming airflow is -20° to 70° (the angle between the blade frontal line and the vertical line), and the adjustment accuracy is not less than 0.10°. The main parameters of the test are also collected in the test section; Figure 4 The disc mechanism of the test section is shown, and its function is to achieve adjustable blade inlet angle of attack, adjustable upper and lower single plate heights, and manual adjustment.

[0054] The rectangular holes 5 opened on the inner disk 3 and the outer disk 4 in this embodiment are of different sizes, forming stepped rectangular holes, and multiple threaded holes are opened around the inner disk 3 and the outer disk 4. Since the distance between the inner disk 3 and the outer disk 4 is relatively limited during actual use, there are two ways to install the cascade test piece: one is to make the cascade test piece into a whole and embed it in the stepped rectangular hole, and the other is to first install the upper mounting plate on the inner disk 3 by multiple bolts, then install multiple cascades on the upper mounting plate, and then install the lower mounting plate on the multiple cascades and on the outer disk 4 at the same time. The entire installation process takes into account that different cascade test pieces are suitable for different installation methods, and the test is more flexible.

[0055] In actual use, the inner disc 3 and the outer disc 4 are positioned and connected by multiple latches, which ensures the reliability of the connection between the inner disc 3 and the outer disc 4 and the consistency of the angle during the rotation. In addition, the latches between the inner disc 3 and the outer disc 4 are easy and quick to insert.

[0056] Specific implementation method five: Combination Figure 6 and Figure 8 To explain this embodiment, the positioning block assembly of this embodiment includes an upper positioning block 6 and a lower positioning block 7, which are fixedly mounted on the air inlet side of the inner shell 1 and the outer shell 2, and are arranged in parallel with each other. Other components and connection relationships are the same as those of the first embodiment.

[0057] The upper positioning block 6 and the lower positioning block 7 of this embodiment play a role in connecting the inner shell 1 and the outer shell 2, and also play a role in the airflow inlet, providing the largest diameter part in the air inlet channel. During the installation process, the upper positioning block 6 and the lower positioning block 7 as well as the inner shell 1 and the outer shell 2 are connected by bolts. Under the action of the bolts, the lower positioning block 7 also plays a fixing role, preventing the lower shrinkage wall plate from changing its position during the movement process.

[0058] Specific implementation method six: Combination Figure 6 and Figure 8 To explain this embodiment, the end of the lower positioning block 7 of this embodiment is provided with a 45° bevel.

[0059] Such arrangement ensures that the lower shrinkage wall plate moves along its bevel during movement, with smooth transition and high movement precision of the lower shrinkage wall plate. Other components and connection relationships are the same as those of the first or second specific implementation.

[0060] Specific implementation method seven: Combination Figure 6To illustrate this embodiment, the connection limiter of this embodiment includes a distance sleeve 8 and a bolt 9. The bolt 9 passes through the outer shell 2 and is inserted into the distance sleeve 8 between the inner shell 1 and the outer shell 2, and extends out of the inner shell 1, and is then installed on the inner shell 1 through a nut.

[0061] In this way, in the connection mode between the inner shell 1 and the outer shell 2, the present embodiment does not directly use bolts for connection, but a distance sleeve 8 is mounted on the bolt, which can not only realize the positioning function, but also play a connecting role. The other components and connection relationships are the same as any one of the specific embodiments 1 to 3.

[0062] This embodiment also has the function of convenient disassembly and assembly, which is mainly reflected in that when testing different blade grid test pieces, different lengths of the distance sleeves 8 can be selected, which has a wide range of applications and is more flexible. One test machine can be used to test blade grids of various models.

[0063] Specific implementation method eight: Combination Figure 1 To illustrate this embodiment, the attack angle adjustment drive component of this embodiment includes a worm wheel 10, a worm 11, a handle 12, a steering assembly 13, and a worm mounting seat 14. The worm wheel 10 is fixedly mounted on the circumferential wall of the outer side of the inner disk 3, the worm mounting seat 14 is mounted on the inner housing 1, the worm 11 is rotatably mounted on the worm mounting seat 14, the steering assembly 13 is mounted on one end of the worm 11, the handle 12 is connected to the steering assembly 13, and the handle 12 drives the worm 11 to rotate after being turned by the steering assembly 13, and the worm 11 is meshed with the worm wheel 10.

[0064] In this way, the angle of attack adjustment drive is mainly used to realize the rotation drive of the inner disk 3 and the outer disk 4. Since the air intake channel is fixed, when the rotation angle of the inner disk 3 and the outer disk 4 changes, the airflow impacts the position on the blade cascade at different positions, thereby realizing the test of different angles of attack. The other structures and components are the same as any one of the specific embodiments 1 to 4.

[0065] The worm wheel 10 in this embodiment uses one-third or one-half of the worm wheel strip, and the worm wheel 10 is installed on the inner casing 1 close to the air intake side, that is, the rotation angle of the cascade test piece is preferably 30°-90°. This angle can meet most angle of attack tests.

[0066] The steering assembly 13 of this embodiment preferably adopts a bevel gear set to achieve steering, which has a simple structure and stable steering, and is more suitable for high temperature environments.

[0067] This embodiment uses a handle as the driving force, and does not use a motor or other forms. One reason is that the high temperature environment during the test process is taken into consideration. The motor working at high temperature is prone to adverse effects. The other reason is that manual control can adjust the rotation angle at any time.

[0068] Specific implementation method nine: Combination Figure 6 To illustrate this embodiment, the upper baffle assembly of this embodiment includes an upper retractable wall plate 15, a rotating connection 16, an upper lifting connection 17 and an upper nut screw pair 18. One end of the upper retractable wall plate 15 is rotatably mounted on the upper positioning block 6 via the rotating connection 16, the upper nut screw pair 18 is mounted on the inner shell 1, and the screw end of the upper nut screw pair 18 is connected to the other end of the upper retractable wall plate 15 via the upper lifting connection 17.

[0069] Such a configuration mainly serves to lift and lower the upper shrinkage panel 15. When the upper shrinkage panel 15 is lifted, it is suitable for preventing the upper shrinkage panel 15 from interfering when installing the cascade test piece. When the upper shrinkage panel 15 is lowered, it is suitable for abutting the upper part of the cascade test piece after installing the cascade test piece, thereby further fixing the cascade. Other components and connection relationships are the same as any one of the specific embodiments 1 to 3.

[0070] This embodiment uses an upper nut screw pair 18 to connect the end of the upper contraction wall plate 15, so that the blade can maintain its posture state unchanged during the impact of airflow and achieve self-locking.

[0071] Specific implementation method ten: Combination Figure 6 To illustrate this embodiment, the lower baffle assembly of this embodiment includes a lower shrinkage wall plate 19, two lifting supports 20, a lower lifting connection member 21 and a lower nut screw pair 22. The curved portion of the lower shrinkage wall plate 19 is attached to the end of the lower positioning block 7 and installed on the inner shell 1, and the lower end of the horizontal portion of the lower shrinkage wall plate 19 is connected to the lower nut screw pair 22 installed on the inner shell 1 through the lower lifting connection member 21. The two lifting supports 20 are respectively installed at the curved portion and the lower end of the horizontal portion of the lower shrinkage wall plate 19.

[0072] Such arrangement facilitates the lower retractable wall plate 19 to move up and down and drag the blade cascade test piece. Other components and connection relationships are the same as any one of the specific embodiments 1 to 6.

[0073] Specific implementation method eleven: Combination Figure 6 and Figure 8 To explain this embodiment, in this embodiment, the channel aperture formed between the upper shrink wall plate 15 and the lower shrink wall plate 19 gradually decreases from the air intake side.

[0074] In this way, by contracting the intake airflow, it is ensured and simulated that the airflow entering the cascade test piece conforms to the actual situation of the model. The other components are the same as any one of the specific implementation modes 1 to 7.

[0075] As a preferred manner, the air flow channel in this embodiment has a constant diameter near the cascade test piece, that is, the upper contraction wall plate 15 and the lower contraction wall plate 19 are arranged in parallel.

[0076] Specific implementation method 12: Combination Figure 8 To illustrate this embodiment, the lifting support member 20 of this embodiment includes a bracket 20-1, a slide rail 20-2 and a slider 20-3. The slide rail 20-2 is obliquely installed on the inner shell 1, and the slider 20-3 is slidably installed on the slide rail 20-2. One end of the bracket 20-1 is connected to the slider 20-3, and the other end of the bracket 20-1 is connected to the lower retractable wall panel 19.

[0077] Such arrangement facilitates the support of the lower shrinkage wall plate 19, and the lower shrinkage wall plate 19 is smooth and does not get stuck during the lifting and lowering process. The other components are the same as any one of the specific embodiments 1 to 8.

[0078] Furthermore, the slide rail 20 - 2 in this embodiment is installed on the inner shell 1 at an angle of 45°, which matches the structural shape of the lower shrinkage wall panel 19 to ensure that no deviation occurs during the lifting and lowering process of the lower shrinkage wall panel 19.

[0079] Specific implementation method 13: Combination Figure 7 To explain this embodiment, this embodiment further includes a four-degree-of-freedom displacement mechanism 23 , which is installed on the outer side of the outer shell 2 .

[0080] Such arrangement facilitates the disk mechanism of the present invention to be accurately moved to the test position for air intake. The other components are the same as any one of the specific embodiments 1 to 9.

[0081] The structure in the test cabin of this embodiment can be disassembled according to the test requirements, and the nozzle section and the test section after the contraction section can be disassembled to provide a three-dimensional space for simulating high-altitude aircraft under low Reynolds number conditions; at the same time, the contraction section can also be designed into a plane and a fan-shaped structure according to the test requirements, thereby realizing a plane blade cascade test and a fan-shaped blade cascade test.

[0082] Specific implementation method 14: Combination Figure 4 To illustrate this embodiment, the secondary flow system C of this embodiment includes an air compressor C-31, a dryer C-32, a gas tank C-33, a first switch valve C-34, a first regulating valve C-35 and a flow meter C-36. The air compressor C-31, the dryer C-32, the gas tank C-33, the first switch valve C-34, the first regulating valve C-35 and the flow meter C-36 are connected in sequence.

[0083] Such arrangement facilitates the introduction of airflow into the test section. The other components are the same as any one of the specific implementation modes 1 to 9.

[0084] Specific implementation method 15: Combination Figure 4 To illustrate this embodiment, the secondary flow system C in this embodiment also includes an electrical system E, a test system F, a video monitoring system G, auxiliary process equipment H and a cooling water system I.

[0085] The electrical system E, the test system F, the video monitoring system G and the auxiliary process equipment H are electrically connected to the air intake system A, the wind tunnel body B and the secondary flow system C respectively, and the cooling water system I is connected to the exhaust system D.

[0086] Such arrangement facilitates the control of the entire wind tunnel test. The other components are the same as any one of the specific implementation modes 1 to 9.

[0087] Specific implementation method 16: Combination Figure 4 To explain this embodiment, the exhaust system D of this embodiment includes a second expansion joint D-41, a heat exchanger D-42, a plurality of second switch valves D-43 and a plurality of vacuum pumps D-44.

[0088] A plurality of second switch valves D-43 are connected in parallel, and each second switch valve D-43 is connected to a vacuum pump D-44. The second expansion joint D-41 and the heat exchanger D-42 are connected and then connected to the plurality of second switch valves D-43 arranged in parallel.

[0089] Such arrangement facilitates exhaust. The other components are the same as any one of the specific embodiments 1 to 9.

[0090] Combination Figures 1 to 11 To illustrate the working principle of the present invention:

[0091] According to the test requirements, the cascade test can consider the influence of secondary flow, that is, the mixing test of cooling air (secondary flow) and mainstream flow, and the cooling effect of cooling air flow on turbine blades. The layout of the secondary flow system is as follows: Figure 1 As shown, its structure includes an air compressor, a dryer, a pressure-stabilizing tank, a switch valve, a regulating valve and a flow meter.

[0092] The airflow passing through the experimental cabin is discharged into the exhaust system. If a high-temperature test is performed, the incoming air needs to be cooled by heat exchange to reach the working range of the vacuum pump. The vacuum pump can then be used for suction. The heat exchanger D-42 uses water cooling for heat exchange.

[0093] Test system F mainly includes conventional test system and special test system. Conventional test system mainly includes gas path pressure measurement and temperature measurement. The measured parameters provide test basis for wind tunnel test condition adjustment. Special test system is mainly determined according to the test requirements of the test section, such as related flow field test, heat exchange test, optical test, etc.

[0094] The control system of the wind tunnel test bench (video monitoring system G) is mainly composed of the blade performance analysis system, the suction unit control system, the valve control system, the displacement mechanism remote control system, the actuator (electrically controlled switch valve, electronically controlled regulating valve, motion controller, displacement mechanism, stepper motor), and measurement sensors (analog pressure sensor, grating ruler, etc.). The overall architecture of the control system is shown in the figure below. Fig. 9 shown.

[0095] The measurement signal sent by the measuring sensor is converted into an engineering value after being processed by the corresponding acquisition module or measuring instrument and displayed on the computer; at the same time, the test status value is output manually or automatically through the computer operation interface, and the output signal of the control board is used to drive the corresponding electrical actuator, so that the actuator completes the corresponding action to achieve the test requirement state.

[0096] The "suction unit control system" enables safe and smooth start and shutdown of the unit.

[0097] The "valve control system" automatically or manually controls the electronically controlled switch valve and electronically controlled regulating valve of the test equipment's air supply pipeline, air exhaust pipeline, bypass air intake pipeline according to the test status, so as to achieve the air pressure state required for the tester's suction test and air-cooled mixing test.

[0098] The "displacement mechanism proximal control system" completes the control of the four-degree-of-freedom displacement mechanism, controls the position and posture of the probe, and realizes the measurement of the test piece outlet flow field and the test piece inlet boundary layer. The four-degree-of-freedom displacement mechanism includes three linear degrees of freedom (X, Y, Z directions) and one α-angle degree of freedom around the Z direction.

[0099] When the inlet size of the test section is 90 mm × 300 mm, the inlet is throttled, the inlet pressure of the test piece is 10 kPa, the temperature is heated to 800 K, and the maximum mass flow rate is 3.3 kg / s, the relationship between the inlet flow rate of the test piece and the Mach number is as follows: Fig.10 As shown in the figure, when the inlet pressure is 10kPa and the temperature is 800K, the maximum mass flow rate is 0.33kg / s; when the blade cascade test aspect ratio is 2, the blade cascade chord length is 50mm, and the inlet temperature is 800K, the relationship between the incoming flow Mach number and the Reynolds number is as follows Fig.11 As shown in the figure, when the Mach number is 0.7, the maximum Reynolds number is 1.6953×10 4 .

[0100] Assembly of the cascade test piece:

[0101] Blade-shaped holes are opened on the upper mounting plate and the lower mounting plate, and a plurality of blade cascades are sequentially mounted in the blade-shaped holes on the upper mounting plate and the lower mounting plate from top to bottom to form a blade cascade to be tested.

[0102] Installation of the cascade test piece:

[0103] The blade test piece is installed in the rectangular holes of the inner disk and the outer disk by bolts.

[0104] Adjustment of the attack angle of the cascade test piece:

[0105] When the angle of attack needs to be adjusted for the cascade test, the handle is turned, and after the steering assembly is turned, the worm is driven to rotate, the worm drives the worm wheel to rotate, and the worm wheel drives the inner and outer discs to rotate at the same time. Since the cascade test piece is installed on the inner and outer discs, the angle of attack of the cascade test piece can be changed by rotating the worm wheel and worm when the direction of the inlet airflow remains unchanged.

[0106] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A temperature-controllable open low Reynolds number intelligent wind tunnel, characterized by: It includes the air intake system (A), the wind tunnel body (B), the secondary flow system (C) and the exhaust system (D). The air intake system (A) comprises an air intake device (A-11), a main air intake regulating valve (A-12), an auxiliary air intake regulating valve (A-13), an air intake heater (A-14) and a first expansion joint (A-15); the air intake device (A-11) is connected to the air intake heater (A-14) through the main air intake regulating valve (A-12) and the auxiliary air intake regulating valve (A-13) arranged in parallel, and the air flow drawn from the atmosphere by the air intake device (A-11) enters the first expansion joint (A-15) after being heated by the air intake heater (A-14); the first expansion joint (A-15) is connected to the wind tunnel body (B), the secondary flow system (C) is connected to the experimental cabin (B-23) in the wind tunnel body (B), and the exhaust system (D) is connected to the exhaust side of the experimental cabin (B-23).

2. A temperature-controllable open low Reynolds number intelligent wind tunnel according to claim 1, characterized in that: The air intake system (A) further comprises a flow guide device (A-16) and an air intake pipe (A-17), wherein the flow guide device (A-16) and the air intake pipe (A-17) are installed between the air intake device (A-11) and the main air intake regulating valve (A-12); The guide device (A-6) includes a conical shell and a metal mesh, the conical shell is connected in sequence with the air intake pipe (A-17), and the metal mesh is installed at the large end of the conical shell, wherein the metal mesh includes an outer metal mesh and an inner metal mesh, and the outer metal mesh and the inner metal mesh are installed in sequence at the large end of the conical shell.

3. A temperature-controllable open low Reynolds number intelligent wind tunnel according to claim 2, characterized in that: The wind tunnel body (B) includes a diffusion section (B-21), a stabilization section (B-22) and a test chamber (B-23), and the diffusion section (B-21), the stabilization section (B-22) and the test chamber (B-23) are connected in sequence from left to right, wherein the test chamber (B-23) includes a contraction section (B-24), a nozzle section (B-25) and a test section (B-26), and the contraction section (B-24), the nozzle section (B-25) and the test chamber (B-26) are connected in sequence from left to right.

4. The temperature-controllable open low Reynolds number intelligent wind tunnel according to claim 3, characterized in that: The test section (B-26) comprises an inner shell (1), an outer shell (2), a positioning block assembly, a plurality of connection limit members, an inner disc (3), an outer disc (4), an angle of attack adjustment drive member, an upper baffle assembly and a lower baffle assembly; the inner shell (1) and the outer shell (2) are connected via a plurality of connection limit members, the positioning block assembly is mounted on the air inlet side of the inner shell (1) and the outer shell (2), one end of the upper baffle assembly is rotatably connected to the positioning block assembly and is used to be clamped on the upper part of the blade of the blade to be tested, and the lower baffle assembly is slidably matched with the side of the positioning block assembly and moves up and down, so as to be used to The inner disc (3) and the outer disc (4) are respectively rotatably mounted on the inner shell (1) and the outer shell (2), and rectangular holes (5) are respectively opened on the inner disc (3) and the outer disc (4), wherein the blade to be tested is mounted in the rectangular hole (5), and scales are engraved on the outer side of the inner shell (1) to measure the rotation angles of the inner disc (3) and the outer disc (4), and an angle of attack adjustment driving member is mounted on the outer side of the inner disc (3), and the angle of attack adjustment driving member drives the inner disc (3) and the outer disc (4) to rotate simultaneously, so as to change the angle of attack of the blade to be tested.

5. The temperature-controllable open low Reynolds number intelligent wind tunnel according to claim 4, characterized in that: The positioning block assembly comprises an upper positioning block (6) and a lower positioning block (7), wherein the upper positioning block (6) and the lower positioning block (7) are fixedly mounted on the air inlet side of the inner shell (1) and the outer shell (2), and the upper positioning block (6) and the lower positioning block (7) are arranged in parallel.

6. The temperature-controllable open low Reynolds number intelligent wind tunnel according to claim 5, characterized in that: The end of the lower positioning block (7) is provided with a 45° bevel.

7. The temperature-controllable open low Reynolds number intelligent wind tunnel according to claim 6, characterized in that: The connection limiter comprises a distance sleeve (8) and a bolt (9). The bolt (9) passes through the outer shell (2) and is inserted into the distance sleeve (8) between the inner shell (1) and the outer shell (2), and extends out of the inner shell (1), and is then mounted on the inner shell (1) via a nut.

8. A temperature-controllable open low Reynolds number intelligent wind tunnel according to claim 1 or 7, characterized in that: The secondary flow system (C) includes an air compressor (C-31), a dryer (C-32), a gas tank (C-33), a first switch valve (C-34), a first regulating valve (C-35) and a flow meter (C-36). The air compressor (C-31), the dryer (C-32), the gas tank (C-33), the first switch valve (C-34), the first regulating valve (C-35) and the flow meter (C-36) are connected in sequence.

9. The temperature-controllable open low Reynolds number intelligent wind tunnel according to claim 8, characterized in that: It also includes electrical system (E), test system (F), video surveillance system (G), auxiliary process equipment (H) and cooling water system (I). The electrical system (E), test system (F), video monitoring system (G) and auxiliary process equipment (H) are electrically connected to the air intake system (A), wind tunnel body (B) and secondary flow system (C), respectively, and the cooling water system (I) is connected to the exhaust system (D).

10. A temperature-controllable open low Reynolds number intelligent wind tunnel according to claim 1 or 9, characterized in that: The exhaust system (D) includes a second expansion joint (D-41), a heat exchanger (D-42), a plurality of second switch valves (D-43) and a plurality of vacuum pumps (D-44). A plurality of second switch valves (D-43) are connected in parallel, each second switch valve (D-43) is connected to a vacuum pump (D-44), and the second expansion joint (D-41) and the heat exchanger (D-42) are connected to the plurality of second switch valves (D-43) arranged in parallel.

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