Wind tunnel test method and apparatus for simulating exhaust of boundary layer from an inlet duct using a tail nozzle

Abstract

This invention discloses a wind tunnel testing method and apparatus for simulating the discharge of boundary layer from an air intake via a tail nozzle, belonging to the field of aircraft simulation technology. It solves the problems of existing traditional wind tunnel testing methods and apparatus, which struggle to simulate actual boundary layer airflow discharge and analyze the impact of the boundary layer on air intake performance and distortion. This invention utilizes an air intake model, measurement section, flow meter, throttling device, and tail nozzle jet flow simulation technology, combined with the use of dynamic sensors. The boundary layer pipeline is connected to the tail nozzle slot, simulating the jet flow generated at the tail nozzle outlet. This jet flow is then guided through the tail nozzle slot, and the boundary layer, after entering the boundary layer pipeline, is influenced by the jet flow from the tail nozzle and discharged through the tail nozzle slot. By studying the boundary layer flow rate changes within a scaled-down model, the impact of the boundary layer on air intake performance and distortion is analyzed. This invention provides effective technical support for the stability and safety design of aircraft air intake systems and can be applied to wind tunnel testing.

Description

Technical Field

[0001] This invention relates to wind tunnel testing methods and apparatus, and more particularly to wind tunnel testing methods and apparatus for simulating the discharge of the boundary layer from the air intake through the tail nozzle, belonging to the field of aircraft simulation technology. Background Technology

[0002] Future aircraft will face more complex flight environments, placing higher demands on the overall performance of the propulsion system. This requires the fuselage, air intake, and engine to achieve good aerodynamic matching. There are strong interactions between the various parts of the propulsion system, and unsteady aerodynamic problems will directly affect the stability and dynamic performance of the system. In terms of the air intake / engine system, unsteady aerodynamic problems in the air intake not only affect the working stability of the engine, but also increase the airflow loss in the air intake, leading to instability in the air intake and, in extreme cases, even damage to the air intake structure.

[0003] During flight, air first flows over the fuselage or leading edge of the wing of the aircraft, forming a boundary layer. When this air reaches the inlet of the air intake, there is already a developing boundary layer at the inlet. If this low-energy, turbulent boundary layer air is allowed to directly enter the engine, it will cause a series of serious problems as follows: (1) The boundary layer air pressure is low, which will lead to a decrease in the total pressure of the airflow entering the engine compression components, thereby reducing the thrust and efficiency of the engine; (2) The airflow in the boundary layer is unstable and uneven. When this unstable and uneven airflow enters the engine fan and compressor, the compressor blades cannot work under the distorted airflow, which may cause stall or even surge. This is a very dangerous engine operating condition, which may lead to engine shutdown or structural damage; (3) The uneven airflow will cause the blades to bear periodic asymmetric loads, causing high-frequency vibration, which may lead to fatigue fracture; (4) The low-energy boundary layer air accumulates on the inner wall of the air intake, thickening the separation zone and increasing internal resistance.

[0004] In summary, a wind tunnel testing method and apparatus are needed to simulate the use of the tail nozzle to expel the boundary layer from the air intake. Summary of the Invention

[0005] A brief overview of the invention is given below to provide a basic understanding of certain aspects of it. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit the scope of the invention. Its purpose is merely to present certain concepts in a simplified form as a prelude to the more detailed description that follows.

[0006] In view of this, in order to solve the problem of simultaneously simulating the ejection and removal of boundary layer by the tail nozzle jet in traditional wind tunnel tests, and analyzing the impact of the boundary layer on the performance and distortion of the inlet, the present invention provides a wind tunnel test method and apparatus for simulating the removal of boundary layer from the inlet by the tail nozzle.

[0007] Technical Solution 1 is as follows: A wind tunnel test method and apparatus for simulating the discharge of the boundary layer from the air intake through the tailpipe, comprising the following steps:

[0008] S1. Install and set up a wind tunnel test device at the wind tunnel test site to simulate the use of the tail nozzle to discharge the boundary layer of the air intake;

[0009] S2. Conduct preliminary debugging of the throttling device and tail nozzle to ensure that they meet the requirements of wind tunnel testing;

[0010] S3. Based on the settings in steps S1 and S2, start the wind tunnel test. Once the Mach number flow field of the wind tunnel is stable, readjust the tail nozzle and throttling device, and collect all the inlet performance and distortion data of the inlet boundary layer flow.

[0011] S4. Repeat the above steps multiple times according to different working conditions. By analyzing the intake performance and distortion data under different conditions, obtain the influence of the hammer wave on the intake flow path load and complete the wind tunnel test simulating the discharge of the intake boundary layer using the tail nozzle.

[0012] Furthermore, in S1, a measurement section is installed at the outlet of the intake duct model. The measurement section contains steady-state total and static pressure measurement rakes and dynamic sensor total pressure measurement rakes, which are used for total pressure and static pressure recovery data and dynamic distortion data acquisition, respectively.

[0013] The air intake model is fixed on the wind tunnel support rod, the rear end of the measuring section is connected to a flow meter, and the rear end of the flow meter is connected to a throttling device.

[0014] A total and static pressure measuring rake is installed in the boundary layer pipeline, which is used to measure the flow rate in the entire boundary layer pipeline.

[0015] The flow meter is equipped with total and static pressure measuring rakes for measuring flow throughout the entire pipeline.

[0016] A flow stabilizing orifice plate and its total and static pressure measuring rakes are installed at the front end of the tail nozzle, which are used to measure the flow rate, total pressure, static pressure and pressure ratio in the entire tail nozzle pipeline.

[0017] Furthermore, in S2, the throttling device is adjusted to ensure that the intake duct is adjusted to achieve the corresponding flow rate according to the test requirements during wind tunnel testing, and the jet pressure ratio of the tail nozzle is adjusted so that an ejector is generated at the boundary layer outlet position of the intake duct and the required flow rate is achieved.

[0018] Furthermore, in step S3, the jet pressure ratio of the tail nozzle is adjusted and kept constant to generate a stable ejection at the boundary layer outlet of the inlet and achieve the required flow rate. After the entire flow field from the boundary layer inlet to the outlet of the inlet stabilizes, the throttling device is adjusted to throttle the flow so that the inlet flow rate reaches the required flow rate for the test. After the entire flow field from the inlet to the outlet of the inlet stabilizes, test data is collected, and the next inlet flow rate is entered. The above process is repeated until all inlet performance and distortion data of the inlet boundary layer flow rate are obtained.

[0019] Furthermore, in step S4, the influence of the hammer wave on the inlet flow path load, i.e., the influence of the overall flow rate change in the boundary layer on the inlet performance and distortion, is analyzed, including the following steps:

[0020] S41. The total pressure recovery data collected by the steady-state total pressure measuring rake in the measurement section is processed to be dimensionless to obtain the total pressure recovery variation law with flow rate under different inlet flow rates;

[0021] In step S41, total pressure recovery... Represented as:

[0022]

[0023]

[0024] in, For total pressure recovery, To measure the average total pressure on the surface, The free-flow steady-state total pressure is expressed in Pa. The total pressure at measurement point (i, j) in the measurement surface, where i is the number of measurement rings in the measurement section, and j is the number of measurement points per ring in the measurement section;

[0025] Based on the data collected from the measurement section, according to the model throat area Calculate the flow coefficient ;

[0026] Flow coefficient Represented as:

[0027]

[0028] in, The steady-state total pressure at pressure measuring point j on ring i of the pressure measuring rake is expressed in Pa. The area of ​​the surface element represented by the measurement point. For stream functions, , The static pressure at the outlet section is the arithmetic mean.

[0029] Based on the above parameters, the curves of total pressure recovery at each flow point in the intake duct as a function of flow rate were plotted, and the law of total pressure recovery as a function of flow rate under different intake duct flow rates was analyzed.

[0030] S42. The dynamic distortion data collected by the dynamic sensor total pressure measuring rake in the measurement section is processed into dimensionless form to obtain the dynamic distortion variation law with flow rate under different intake flow rates.

[0031] In step S42, the turbulence intensity is calculated based on the results measured at the dynamic total pressure measurement point and the static pressure measurement point on the wall. Set the effective measurement time T seconds for dynamic total pressure measurement;

[0032]

[0033]

[0034]

[0035] in, This represents the standard root mean square value of the pulsating pressure. Let k be the turbulence intensity of the channel. This is the sensor coefficient, expressed in Pa / μV. For amplifiers and filters, A / D represents the system calibration coefficients. The AC component of the dynamic signal is expressed in μV. This indicates the number of data collected by the k-th channel. Each pulsed pressure, v=1,2...60000, The sampling frequency;

[0036] Based on the above parameters, the curves of dynamic distortion at the intake outlet as a function of flow coefficient under different flow rates were plotted, and the dynamic distortion as a function of flow rate under different intake flow rates were analyzed.

[0037] S43. Under the same conditions, determine whether the total pressure recovery data and intake duct distortion data meet the design specifications;

[0038] S44. Based on the working requirements of the intake duct, determine the impact of boundary layer flow rate under different nozzle pressure ratios on total pressure recovery data and intake duct distortion data;

[0039] In step S43, the pressure ratio data is dimensionless, and the boundary layer flow data is processed to obtain the measured flow rate. ;

[0040] The process of dimensionless processing of pressure ratio data is expressed as follows:

[0041]

[0042] in, The total pressure at the tail nozzle. For wind tunnel static pressure;

[0043] Actual flow rate Represented as:

[0044]

[0045] in, The free-flow total temperature is expressed in Kelvin (K), and n is a constant, n = 0.040414196.

[0046] S45. By measuring the changes in total pressure recovery data and dynamic distortion data of the inlet based on different Mach numbers, inlet flow rate, and boundary layer flow rate, determine whether the overall design data of the inlet and boundary layer are within the design specifications.

[0047] Technical Solution 2: A wind tunnel test device simulating the discharge of the boundary layer from the intake duct using the tail nozzle, including an intake duct model, a measurement section, a flow meter, a throttling device, wind tunnel support rods, boundary layer, total and static pressure measuring rakes, high-pressure pipelines, flow stabilizing orifice plates, and a tail nozzle;

[0048] The intake duct model is fixed on the wind tunnel support rod. The outlet of the intake duct model is connected to the measurement section. The measurement section is equipped with steady-state total and static pressure measuring rakes and dynamic sensor total pressure measuring rakes. The rear end of the measurement section is connected to a flow meter. The rear end of the flow meter is connected to a throttling device. The boundary layer total and static pressure measuring rakes are installed in the boundary layer pipeline. The front end of the tail nozzle is connected to a high-pressure pipeline. The high-pressure pipeline is equipped with a flow stabilizing orifice plate and its total and static pressure measuring rakes.

[0049] The beneficial effects of this invention are as follows: This invention proposes a wind tunnel test method suitable for studying the working conditions of scaled-down aircraft inlets under different Mach numbers and mass flow rates, simulating the discharge of the boundary layer from the inlet via the tail nozzle; This invention utilizes an inlet model, measurement section, flow meter, throttling device, and tail nozzle jet simulation technology, combined with the use of dynamic sensors, to connect the boundary layer pipeline to the tail nozzle slot, simulating the generation of jet flow at the tail nozzle outlet, which guides the boundary layer through the tail nozzle slot. After entering the boundary layer pipeline, the boundary layer is influenced by the jet flow from the tail nozzle and discharged through the tail nozzle slot. The experimental results are used to study the changes in boundary layer flow rate within the scaled-down model and analyze the impact of the boundary layer on inlet performance and distortion; This invention can provide technical support for evaluating the impact of different boundary layer flow rates discharged from the tail nozzle on the stability and safety design of aircraft inlet systems through experimental techniques. Attached Figure Description

[0050] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0051] Figure 1 A schematic diagram of a wind tunnel test method for simulating the discharge of the boundary layer from the intake duct using the tail nozzle;

[0052] Figure 2 A schematic diagram of a wind tunnel test device for simulating the discharge of the boundary layer from the intake duct using the tail nozzle.

[0053] Figure descriptions: 1. Wind tunnel inlet flow; 2. Test wind tunnel; 3. Inlet model; 4. Measurement section; 5. Flow meter; 6. Throttling device; 7. Wind tunnel support rod; 8. Boundary layer; 9. Boundary layer total and static pressure measuring rake; 10. High-pressure pipeline; 11. Flow stabilizing orifice plate and its total and static pressure measuring rake; 12. Tail nozzle; 13. Tail nozzle slot. Detailed Implementation

[0054] To make the technical solutions and advantages of the embodiments of the present invention clearer, the exemplary embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not an exhaustive list of all embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0055] Example 1: Reference Figure 1 and Figure 2 This embodiment describes a wind tunnel test method that simulates the discharge of the boundary layer from the air intake using a tailpipe, specifically including the following steps:

[0056] S1. Install and set up a wind tunnel test device at the wind tunnel test site to simulate the use of the tail nozzle to discharge the boundary layer of the air intake;

[0057] S2. Conduct preliminary debugging of the throttling device and tail nozzle to ensure that they meet the requirements of wind tunnel testing;

[0058] S3. Based on the settings in steps S1 and S2, start the wind tunnel test. Once the Mach number flow field of the wind tunnel is stable, readjust the tail nozzle and throttling device, and collect all the inlet performance and distortion data of the inlet boundary layer flow.

[0059] S4. Repeat the above steps multiple times according to different working conditions. By analyzing the intake performance and distortion data under different conditions, obtain the influence of the hammer wave on the intake flow path load and complete the wind tunnel test simulating the discharge of the intake boundary layer using the tail nozzle.

[0060] Furthermore, in S1, a measurement section is installed at the outlet of the intake duct model. The measurement section contains steady-state total and static pressure measurement rakes and dynamic sensor total pressure measurement rakes, which are used for total pressure and static pressure recovery data and dynamic distortion data acquisition, respectively.

[0061] The air intake model is fixed on the wind tunnel support rod, the rear end of the measuring section is connected to a flow meter, and the rear end of the flow meter is connected to a throttling device.

[0062] A total and static pressure measuring rake is installed in the boundary layer pipeline, which is used to measure the flow rate in the entire boundary layer pipeline.

[0063] The flow meter is equipped with total and static pressure measuring rakes for measuring flow throughout the entire pipeline.

[0064] A flow stabilizing orifice plate and its total and static pressure measuring rakes are installed at the front end of the tail nozzle, which are used to measure the flow rate, total pressure, static pressure and pressure ratio in the entire tail nozzle pipeline.

[0065] Furthermore, in S2, the throttling device is adjusted to ensure that the intake duct is adjusted to achieve the corresponding flow rate according to the test requirements during wind tunnel testing, and the jet pressure ratio of the tail nozzle is adjusted so that an ejector is generated at the boundary layer outlet position of the intake duct and the required flow rate is achieved.

[0066] Furthermore, in step S3, the jet pressure ratio of the tail nozzle is adjusted and kept constant to generate a stable ejection at the boundary layer outlet of the inlet and achieve the required flow rate. After the entire flow field from the boundary layer inlet to the outlet of the inlet stabilizes, the throttling device is adjusted to throttle the flow so that the inlet flow rate reaches the required flow rate for the test. After the entire flow field from the inlet to the outlet of the inlet stabilizes, test data is collected, and the next inlet flow rate is entered. The above process is repeated until all inlet performance and distortion data of the inlet boundary layer flow rate are obtained.

[0067] Furthermore, in step S4, the influence of the hammer wave on the inlet flow path load, i.e., the influence of the overall flow rate change in the boundary layer on the inlet performance and distortion, is analyzed, including the following steps:

[0068] S41. The total pressure recovery data collected by the steady-state total pressure measuring rake in the measurement section is processed to be dimensionless to obtain the total pressure recovery variation law with flow rate under different inlet flow rates;

[0069] In S41, Represented as:

[0070]

[0071]

[0072] in, For total pressure recovery, To measure the average total pressure on the surface, The free-flow steady-state total pressure is expressed in Pa. The total pressure at measurement point (i, j) in the measurement surface, where i is the number of measurement rings in the measurement section, and j is the number of measurement points per ring in the measurement section;

[0073] Based on the data collected from the measurement section, according to the model throat area Calculate the flow coefficient ;

[0074] Flow coefficient Represented as:

[0075]

[0076] in, The steady-state total pressure at pressure measuring point j on ring i of the pressure measuring rake is expressed in Pa. The area of ​​the surface element represented by the measurement point. For stream functions, , The static pressure at the outlet section is the arithmetic mean.

[0077] Based on the above parameters, the curves of total pressure recovery at each flow point in the intake duct as a function of flow rate were plotted, and the law of total pressure recovery as a function of flow rate under different intake duct flow rates was analyzed.

[0078] S42. The dynamic distortion data collected by the dynamic sensor total pressure measuring rake in the measurement section is processed into dimensionless form to obtain the dynamic distortion variation law with flow rate under different intake flow rates.

[0079] In step S42, the turbulence intensity is calculated based on the results measured at the dynamic total pressure measurement point and the static pressure measurement point on the wall. Set the effective measurement time for dynamic total pressure measurement to T=3 seconds;

[0080]

[0081]

[0082]

[0083] in, This represents the standard root mean square value of the pulsating pressure. Let k be the turbulence intensity of the channel. This is the sensor coefficient, expressed in Pa / μV. For amplifiers and filters, A / D represents the system calibration coefficients. The AC component of the dynamic signal is expressed in μV. This indicates the number of data collected by the k-th channel. Each pulsed pressure, v=1,2...60000, This is the sampling frequency; in this embodiment, it is set to 20kHz.

[0084] Based on the above parameters, the curves of dynamic distortion at the intake outlet as a function of flow coefficient under different flow rates were plotted, and the dynamic distortion as a function of flow rate under different intake flow rates were analyzed.

[0085] S43. Under the same conditions, determine whether the total pressure recovery data and intake duct distortion data meet the design specifications;

[0086] S44. Based on the working requirements of the intake duct, determine the impact of boundary layer flow rate under different nozzle pressure ratios on total pressure recovery data and intake duct distortion data;

[0087] In step S43, the pressure ratio data is dimensionless, and the boundary layer flow data is processed to obtain the measured flow rate. ;

[0088] The process of dimensionless processing of pressure ratio data is expressed as follows:

[0089]

[0090] in, The total pressure at the tail nozzle. For wind tunnel static pressure;

[0091] Actual flow rate Represented as:

[0092]

[0093] in, The free-flow total temperature is expressed in Kelvin (K), and n is a constant, n = 0.040414196.

[0094] S45. By measuring the changes in total pressure recovery data and dynamic distortion data of the inlet based on the different Mach numbers, inlet flow rate, and boundary layer flow rate obtained, determine whether the overall design of the inlet and boundary layer meets the design specifications.

[0095] Specifically, at a Mach number of 0.5, with an inlet flow rate of 100 kg / s and a boundary layer flow rate of 10 kg / s, the design parameters for total pressure recovery data and dynamic distortion data were greater than 0.9 and less than 0.05, respectively. The final measured total pressure recovery data and dynamic distortion data were 0.91 and 0.045, respectively, which met the design requirements.

[0096] Example 2: Reference Figure 2This embodiment describes a wind tunnel test apparatus that simulates the discharge of the boundary layer from the inlet using a tail nozzle. It is used to perform the wind tunnel test method described in Embodiment 1 that simulates the discharge of the boundary layer from the inlet using a tail nozzle. The apparatus includes an inlet model 3, a measuring section 4, a flow meter 5, a throttling device 6, a wind tunnel support rod 7, a boundary layer 8, a boundary layer total and static pressure measuring rake 9, a high-pressure pipeline 10, a flow stabilizing orifice plate and its total and static pressure measuring rake 11, and a tail nozzle 12.

[0097] The intake duct model 3 is fixed on the wind tunnel support rod 7. The outlet of the intake duct model 3 is connected to the measurement section 4. The measurement section 4 is equipped with a steady-state total and static pressure measuring rake and a dynamic sensor total pressure measuring rake. The rear end of the measurement section 4 is connected to the flow meter 5. The rear end of the flow meter 5 is connected to the throttling device 6. The boundary layer total and static pressure measuring rake 9 is installed in the boundary layer 8 pipeline. The front end of the tail nozzle 12 is connected to the high pressure pipeline 10. The high pressure pipeline 10 is equipped with a flow stabilizing orifice plate and its total and static pressure measuring rake 11.

[0098] Specifically, the intake model 3 is arranged in the test wind tunnel 2. After the test begins, the test wind tunnel 2 introduces the wind tunnel flow 1. There is a tail nozzle gap 13 connecting the boundary layer 8 pipeline and the tail nozzle 12. The tail nozzle 12 adopts an active and controllable adjustment method. The inlet of the tail nozzle 12 is connected to the high pressure pipeline 10 and the flow stabilizing orifice plate and its total and static pressure measuring rakes 11 to make the high pressure airflow reaching the tail nozzle 12 uniform. The high pressure airflow is ejected through the tail nozzle 12 and produces an ejection effect on the tail nozzle 12 and the tail nozzle gap 13 at the tail of the model. Thus, by adjusting the pressure ratio of the tail nozzle 12, the flow rate of the boundary layer 8 can be adjusted.

[0099] Although the invention has been described with reference to a limited number of embodiments, those skilled in the art will understand from the foregoing description that other embodiments are conceivable within the scope of the invention described herein. Furthermore, it should be noted that the language used in this specification has been chosen primarily for readability and instructional purposes, and not for the purpose of interpreting or limiting the subject matter of the invention. Therefore, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the invention is illustrative and not restrictive, and the scope of the invention is defined by the appended claims.

Claims

1. A wind tunnel test method for simulating the discharge of the boundary layer from the air intake through the tailpipe, characterized in that, Includes the following steps: S1. Install and set up a wind tunnel test device at the wind tunnel test site to simulate the use of the tail nozzle to discharge the boundary layer of the air intake; In S1, the boundary layer pipeline of the air intake model is connected to the tail nozzle gap to simulate the jet flow generated at the tail nozzle outlet and to guide the tail nozzle gap. S2. Conduct preliminary debugging of the throttling device and tail nozzle to ensure that they meet the requirements of wind tunnel testing; In S2, the throttling device is adjusted to ensure that the intake duct is adjusted to the required flow rate during wind tunnel testing, and the jet pressure ratio of the tail nozzle is adjusted to generate an ejector at the boundary layer outlet of the intake duct and achieve the required flow rate. S3. Based on the settings in steps S1 and S2, start the wind tunnel test. Once the Mach number flow field of the wind tunnel is stable, readjust the tail nozzle and throttling device, and collect all the inlet performance and distortion data of the inlet boundary layer flow. In S3, the jet pressure ratio of the tail nozzle is adjusted and kept constant, so that a stable ejection is generated at the boundary layer outlet position of the inlet and the required flow rate is achieved, and the boundary layer is discharged through the tail nozzle gap. S4. Repeat the above steps multiple times according to different working conditions. By analyzing the intake performance and distortion data under different conditions, obtain the influence of the hammer wave on the intake flow path load and complete the wind tunnel test simulating the discharge of the intake boundary layer using the tail nozzle.

2. The wind tunnel test method for simulating the discharge of the boundary layer from the inlet using the tailpipe as described in claim 1, characterized in that, In S1, a measurement section is installed at the outlet of the air intake model. The measurement section contains steady-state total and static pressure measurement rakes and dynamic sensor total pressure measurement rakes, which are used for total pressure and static pressure recovery data and dynamic distortion data acquisition, respectively. The air intake model is fixed on the wind tunnel support rod, the rear end of the measuring section is connected to a flow meter, and the rear end of the flow meter is connected to a throttling device. A total and static pressure measuring rake is installed in the boundary layer pipeline, which is used to measure the flow rate in the entire boundary layer pipeline. The flow meter is equipped with total and static pressure measuring rakes for measuring flow throughout the entire pipeline. A total and static pressure measuring rake is installed at the front end of the tailpipe, which is used to measure the flow rate, total pressure, static pressure and pressure ratio in the entire tailpipe pipeline.

3. The wind tunnel test method for simulating the discharge of the boundary layer from the inlet using the tail nozzle as described in claim 2, characterized in that, In step S3, after the entire flow field from the inlet to the outlet of the inlet boundary layer stabilizes, the throttling device is adjusted to throttle the flow so that the inlet flow rate reaches the required flow rate for the test. After the entire flow field from the inlet to the outlet of the inlet stabilizes, test data is collected, and the next inlet flow rate is entered. The above process is repeated until all inlet performance and distortion data of the inlet boundary layer flow rate are obtained.

4. The wind tunnel test method for simulating the discharge of the boundary layer from the inlet using the tail nozzle as described in claim 3, characterized in that, In step S4, the analysis of the impact of the hammer wave on the inlet flow path load, i.e., the overall flow rate change of the boundary layer, and its impact on inlet performance and distortion, includes the following steps: S41. The total pressure recovery data collected by the steady-state total pressure measuring rake in the measurement section is processed to be dimensionless to obtain the total pressure recovery variation law with flow rate under different inlet flow rates; In S41, Represented as: in, For total pressure recovery, To measure the average total pressure on the surface, The free-flow steady-state total pressure is expressed in Pa. The total pressure at measurement point (r, i) in the measurement surface, where i is the number of measurement points per ring of the measurement section, and r is the number of measurement rings in the measurement section; Based on the data collected from the measurement section, according to the model throat area Calculate the flow coefficient ; Flow coefficient Represented as: in, The steady-state total pressure at pressure measuring point j on ring i of the pressure measuring rake is expressed in Pa. The area of ​​the surface element represented by the measurement point. For stream functions, , The static pressure at the outlet section is the arithmetic mean. Based on the above parameters, the curves of total pressure recovery at each flow point in the intake duct as a function of flow rate were plotted, and the law of total pressure recovery as a function of flow rate under different intake duct flow rates was analyzed. S42. The dynamic distortion data collected by the dynamic sensor total pressure measuring rake in the measurement section is processed into dimensionless form to obtain the dynamic distortion variation law with flow rate under different intake flow rates. In step S42, the turbulence intensity is calculated based on the results measured at the dynamic total pressure measurement point and the static pressure measurement point on the wall. Set the effective measurement time T seconds for dynamic total pressure measurement; in, This represents the standard root mean square value of the pulsating pressure. Let k be the turbulence intensity of the channel. This is the sensor coefficient, expressed in Pa / μV. For amplifiers and filters, A / D represents the system calibration coefficients. The AC component of the dynamic signal is expressed in μV. This indicates the number of data collected by the k-th channel. Each pulsed pressure, v=1,2...60000, The sampling frequency; Based on the above parameters, the curves of dynamic distortion at the intake outlet as a function of flow coefficient under different flow rates were plotted, and the dynamic distortion as a function of flow rate under different intake flow rates were analyzed. S43. Under the same conditions, determine whether the total pressure recovery data and intake duct distortion data meet the design specifications; S44. Based on the working requirements of the intake duct, determine the impact of boundary layer flow rate under different nozzle pressure ratios on total pressure recovery data and intake duct distortion data; In step S43, the pressure ratio data is dimensionless, and the boundary layer flow data is processed to obtain the measured flow rate. ; The process of dimensionless processing of pressure ratio data is expressed as follows: in, The total pressure at the tail nozzle. For wind tunnel static pressure; Actual flow rate Represented as: in, The free-flow total temperature is expressed in Kelvin (K), and n is a constant, n = 0.040414196. S45. By obtaining the changes in the total pressure recovery data and dynamic distortion data of the inlet based on different Mach numbers, inlet flow rate, and boundary layer flow rate, determine whether the overall design of the inlet and boundary layer meets the design specifications, and complete the wind tunnel test simulating the discharge of the inlet boundary layer using the tail nozzle.

5. A wind tunnel test apparatus for simulating the discharge of the boundary layer from the air intake through the tailpipe, characterized in that, The wind tunnel test method for performing any one of claims 1-4, simulating the discharge of the boundary layer of the inlet using the tail nozzle, includes an inlet model (3), a measuring section (4), a flow meter (5), a throttling device (6), a wind tunnel support rod (7), a boundary layer (8), a boundary layer total and static pressure measuring rake (9), a high-pressure pipeline (10), a flow stabilizing orifice plate and its total and static pressure measuring rake (11), and a tail nozzle (12). The intake duct model (3) is fixed on the wind tunnel support rod (7). The outlet of the intake duct model (3) is connected to the measurement section (4). The measurement section (4) is equipped with a steady-state total and static pressure measuring rake and a dynamic sensor total pressure measuring rake. The rear end of the measurement section (4) is connected to the flow meter (5). The rear end of the flow meter (5) is connected to the throttling device (6). The boundary layer total and static pressure measuring rake (9) is installed in the boundary layer (8) pipeline. The front end of the tail nozzle (12) is connected to the high pressure pipeline (10). The high pressure pipeline (10) is equipped with a flow stabilizing orifice plate and its total and static pressure measuring rake (11) and boundary layer total and static pressure measuring rake (9).

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