Supersonic air inlet channel wind tunnel test model and related parameter calculation method thereof

Abstract

The invention belongs to the technical field of air inlet channel wind tunnel tests, and particularly relates to a supersonic air inlet channel wind tunnel test model and a related parameter calculation method thereof, a simulation machine body and an air inlet channel installed on the simulation machine body. A center cone is installed at an inlet of the air inlet channel and comprises a cone body at the front end and a straight pipe at the rear section, a hollow channel is formed in the straight pipe, a drainage groove for guiding airflow into the hollow channel is formed in the connecting position of the straight pipe and the cone body, the tail of the airflow channel is connected with a drainage pipeline, and a drainage flow measuring rake and a drainage flow control valve are installed in the drainage pipeline. An air inlet channel outlet total pressure measuring rake and a suction pipeline are installed at an air inlet channel outlet, a suction flow control valve is installed in the suction pipeline, and the flow of the air inlet channel is controlled through the suction flow control valve in the suction pipeline. And the air inlet channel aerodynamic performance such as the total pressure recovery coefficient and the distortion index of the air inlet channel under the matching of different air inlet flow rates and various discharge flow rates is obtained.

Description

Technical Field

[0001] This application belongs to the field of inlet wind tunnel testing technology, and specifically relates to a supersonic inlet wind tunnel test model and its related parameter calculation method. Background Technology

[0002] The aerodynamic performance of supersonic inlets needs to meet the requirements of airflow quality across the entire speed range, including low-speed, subsonic, transonic, and supersonic speeds. During supersonic flight, considering the rapid development of the boundary layer, a bleed-out technique is typically employed. This involves creating a bleed-out channel near the throat, which enhances the stability margin of the final shock wave under critical conditions and improves the airflow quality within the inlet. Inlet wind tunnel testing is a crucial technique for obtaining inlet aerodynamic performance data and serves as an important basis for evaluating inlet aerodynamic performance. Supersonic inlet wind tunnel tests considering the effects of bleed-out ducts present several technical challenges, including test model design, bleed-out drainage and flow control, and test data analysis. In terms of test model design, due to the significant difference between the size of the bleed channel and the size of the supersonic airframe, a small scaling ratio is typically used to meet the wind tunnel's requirements for test model size. If the bleed channel size is scaled down to the same ratio as the airframe, the bleed channel width becomes extremely small, potentially leading to a large discrepancy between the bleed effect and the actual flow, directly affecting the reliability of the test results. Similarly, the small model size presents challenges in bleed discharge channel design and flow measurement and control. Furthermore, due to the equivalent design of the model, a special pre-matched test data analysis method must be employed for data analysis. Therefore, developing a wind tunnel test method for supersonic inlets that considers the effects of bleed is of significant practical importance. Summary of the Invention

[0003] To address the aforementioned issues, this application provides a supersonic inlet wind tunnel test model that considers the effects of leakage, comprising:

[0004] The simulator (8) and the air intake (3) installed on the simulator (8);

[0005] A central cone (1) is installed at the inlet of the air intake (3). The central cone (1) includes a cone at the front end and a straight pipe at the rear end. The straight pipe has a hollow channel inside. The connection between the straight pipe and the cone has a venting groove (2) that introduces airflow into the hollow channel. The tail end of the airflow channel is connected to a venting pipe (5). A venting flow measuring rake (6) and a venting flow control valve (7) are installed in the venting pipe (5).

[0006] An intake outlet total pressure measuring rake (4) and a suction pipe (10) are installed at the outlet of the intake duct (3). A suction flow control valve (11) is installed in the suction pipe (10). The intake flow is controlled by the suction flow control valve (11) in the suction pipe (10) to simulate the intake flow of the aircraft under different flight conditions. The steady-state total pressure, dynamic total pressure and static pressure of the airflow at the intake outlet section are measured by the intake outlet total pressure measuring rake (4). Based on this, the intake flow, total pressure recovery coefficient and distortion index are calculated.

[0007] Preferably, the method for calculating the intake airflow is as follows:

[0008] ;

[0009] In the formula, k is the specific heat ratio of air; G is the flow rate at the intake outlet; T0 is the total temperature at the intake outlet; P0 is the total pressure at the intake outlet; and P is the static pressure at the intake outlet.

[0010] Preferably, the discharge pipeline is equipped with a total pressure measuring rake and a wall static pressure measuring point for calculating the flow rate of the discharge pipeline.

[0011] A method for calculating relevant parameters of a supersonic inlet wind tunnel test model, employing the aforementioned supersonic inlet wind tunnel test model considering the influence of leakage, and a method for calculating the steady-state circumferential distortion index, including:

[0012] The average total pressure at the intake duct outlet section is obtained by arithmetic averaging or flow averaging of the steady-state total pressure measurement values ​​obtained from the intake duct outlet total pressure measurement rake (4). ;

[0013] Get the total incoming pressure ;

[0014] Average total pressure at the inlet outlet section With the total pressure of the incoming flow Calculate the total pressure recovery coefficient σ at the intake duct outlet section;

[0015] The intake duct outlet section is divided into multiple sector regions, and the average total pressure recovery coefficient of each sector region is calculated one by one. ;

[0016] The angle corresponding to the j-th measuring rake The x-axis represents the average total pressure recovery coefficient of the sector region. Use the ordinate as the constructor. ;

[0017] Based on functions The minimum average total pressure recovery coefficient is obtained by solving the average total pressure recovery coefficient for each low-pressure zone at the intake outlet section. ;

[0018] Based on the minimum average total pressure recovery coefficient The steady-state circumferential distortion index is calculated using the total pressure recovery coefficient σ at the inlet outlet section. .

[0019] Preferably, the average total pressure at the intake duct outlet section is calculated using an arithmetic mean. The formula is:

[0020] ;

[0021] The number of rake walls for measuring the total pressure at the intake outlet (4) The number of steady-state total pressure measuring tubes for each rake wall.

[0022] Preferably, the average total pressure at the intake duct outlet section is calculated by averaging the flow rate. The formula is:

[0023] ;

[0024] ;

[0025] For flow function, To measure the area of ​​a single surface element in a cross-section.

[0026] Preferably, the mean total pressure recovery coefficient is... The calculation formula is:

[0027] ;

[0028] is the total pressure recovery coefficient at the i-th measurement point in the j-th sector.

[0029] Preferably, the minimum average total pressure recovery coefficient is... The calculation formula is:

[0030] ;

[0031] In the formula, and The starting and ending angles of the low-pressure zone corresponding to the smallest average total pressure recovery coefficient.

[0032] Preferably, the steady-state circumferential distortion index is... The calculation formula is:

[0033] .

[0034] Preferably, turbulence intensity The calculation formula is:

[0035] ;

[0036] in: Let J be the turbulence intensity of the j-th sector.

[0037] ;

[0038] ;

[0039] in, This is the average dynamic total pressure. The dynamic total pressure is the j-th dynamic measurement point at the intake duct outlet section.

[0040] Preferably, the formula for calculating the total pressure distortion index W is:

[0041] The advantages of this application include: under supersonic inflow conditions, this application obtains the intake aerodynamic performance such as the total pressure recovery coefficient and distortion index of the intake under different intake flow rates and various discharge flow rate matches. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of a supersonic inlet wind tunnel test model considering the effect of leakage in a preferred embodiment of this application. Detailed Implementation

[0043] To make the technical solution and advantages of this application clearer, the technical solution of this application will be described in a clearer and more complete manner below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of this application, and are only used to explain this application, not to limit this application. It should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings. Other related parts can be referred to the general design. In the absence of conflict, the embodiments and technical features in the embodiments of this application can be combined with each other to obtain new embodiments.

[0044] Furthermore, it should be noted that, unless otherwise explicitly specified and limited, terms such as “installation,” “connection,” and “linkage” used in the description of this application should be interpreted broadly. For example, a connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; or it can be a connection within two components. Those skilled in the art can understand its specific meaning in this application according to the specific circumstances.

[0045] a) such as Figure 1 As shown, a wind tunnel test model of a supersonic inlet affected by leakage is presented.

[0046] This application provides a supersonic inlet wind tunnel test model that considers the effect of leakage, including:

[0047] The simulator (8) and the air intake (3) installed on the simulator (8);

[0048] A central cone (1) is installed at the inlet of the air intake (3). The central cone (1) includes a cone at the front end and a straight pipe at the rear end. The straight pipe has a hollow channel inside. The connection between the straight pipe and the cone has a venting groove (2) that introduces airflow into the hollow channel. The tail end of the airflow channel is connected to a venting pipe (5). A venting flow measuring rake (6) and a venting flow control valve (7) are installed in the venting pipe (5).

[0049] An intake outlet total pressure measuring rake (4) and a suction pipe (10) are installed at the outlet of the intake duct (3). A suction flow control valve (11) is installed in the suction pipe (10). The intake flow is controlled by the suction flow control valve (11) in the suction pipe (10) to simulate the intake flow of the aircraft under different flight conditions. The steady-state total pressure, dynamic total pressure and static pressure of the airflow at the intake outlet section are measured by the intake outlet total pressure measuring rake (4). Based on this, the intake flow, total pressure recovery coefficient and distortion index are calculated.

[0050] The air intake model is connected to the aircraft body via a pylon. The entire test model is fixed in the wind tunnel test section, and the wind tunnel angle of attack / sideslip angle adjustment structure can be used to adjust the test model to different angles of attack and sideslip angles.

[0051] b) Experimental model

[0052] The scale of the test model is determined based on the dimensions of the test section of the wind tunnel and the air intake capacity. It needs to meet constraints such as blockage requirements, model length and span, and air intake flow requirements. The test model needs to include the fuselage and wings before the air intake, and the air intake lip and internal ducts need to be strictly simulated.

[0053] c) Intake Flow Control and Measurement

[0054] By adjusting the position of the intake flow control valve, the cross-sectional area of ​​the airflow channel in the suction pipeline is changed, thereby controlling the airflow entering the intake duct. A total pressure measuring rake and a wall static pressure measuring point are installed at the intake duct outlet. The intake airflow is calculated using the following formula:

[0055] (1)

[0056] In the formula, k is the specific heat ratio of air; G, T0, P0, and P are the flow rate, total temperature, total pressure, and static pressure at the air intake outlet, respectively.

[0057] d) Discharge flow control and measurement

[0058] By adjusting the position of the flow control valve in the venting pipeline, the cross-sectional area of ​​the airflow channel in the venting pipeline is changed, thereby controlling the flow rate entering the venting pipeline. A total pressure measuring rake and a static pressure measuring point on the wall are set in the venting pipeline, and the venting flow rate is calculated using formula (1). In the calculation, T0, P0, and P are taken as the total temperature, total pressure, and static pressure at the measuring section position in the venting pipeline, respectively.

[0059] e) Experimental data processing methods

[0060] The total pressure recovery coefficient σ of the inlet outlet section is defined as the average total pressure of the inlet outlet section. With free flow total pressure The ratio, i.e.

[0061] (2)

[0062] In the formula, It is obtained by arithmetic average or flow rate average of the steady-state total pressure measured by the measuring rake at the intake outlet.

[0063] The intake manifold outlet total pressure measuring rake (4) includes... Each rake wall is equipped with [various items]. A steady-state total pressure measuring tube, then

[0064] The formula for calculating the arithmetic mean is:

[0065] (3)

[0066] The formula for calculating average flow rate is:

[0067] (4)

[0068] In the formula, For flow function, To measure the area of ​​a single surface element in a cross-section. The calculation formula is:

[0069]

[0070] Steady-state circumferential distortion index The calculation is based on the steady-state total pressure data of the inlet outlet section, and the inlet outlet section is divided into... For each sector, the average total pressure recovery coefficient is calculated sequentially. The calculation formula is as follows:

[0071] (5)

[0072] To measure the angle corresponding to the rake The x-axis represents the average total pressure recovery coefficient of the sector region. Use the ordinate as the constructor. The average total pressure recovery coefficient of each low-pressure zone at the intake duct outlet section is calculated one by one, and the minimum value is taken:

[0073] (6)

[0074] In the formula, and The starting and ending angles of the low-pressure zone corresponding to the minimum average total pressure recovery coefficient. Then, the steady-state circumferential distortion index. The calculation formula is:

[0075] (7)

[0076] Turbulence The calculation is based on dynamic total pressure data from the intake duct outlet section. The number of dynamic total pressure measurement points is generally the same as the number of pressure gauges. Similarly, the intake duct outlet section is divided into... For each sector, the turbulence intensity is calculated sequentially. Finally, the turbulence intensity of all sectors was calculated. Find the arithmetic mean.

[0077] (8)

[0078] in:

[0079]

[0080]

[0081] The total pressure distortion index W is defined as the turbulence intensity. and steady-state circumferential distortion index The sum of, i.e.

[0082] (9)

[0083] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A supersonic inlet wind tunnel test model considering the effect of leakage, characterized in that, include: The simulator (8) and the air intake (3) installed on the simulator (8); A central cone (1) is installed at the inlet of the air intake (3). The central cone (1) includes a cone at the front end and a straight pipe at the rear end. The straight pipe has a hollow channel inside. The connection between the straight pipe and the cone has a venting groove (2) that introduces airflow into the hollow channel. The tail end of the airflow channel is connected to a venting pipe (5). A venting flow measuring rake (6) and a venting flow control valve (7) are installed in the venting pipe (5). An intake outlet total pressure measuring rake (4) and a suction pipe (10) are installed at the outlet of the intake duct (3). A suction flow control valve (11) is installed in the suction pipe (10). The intake flow is controlled by the suction flow control valve (11) in the suction pipe (10) to simulate the intake flow of the aircraft under different flight conditions. The steady-state total pressure, dynamic total pressure and static pressure of the airflow at the intake outlet section are measured by the intake outlet total pressure measuring rake (4). Based on this, the intake flow, total pressure recovery coefficient and distortion index are calculated.

2. The supersonic inlet wind tunnel test model considering the effect of leakage as described in claim 1, characterized in that, The method for calculating the intake airflow is as follows: ； In the formula, k is the specific heat ratio of air; G is the flow rate at the intake outlet; T0 is the total temperature at the intake outlet; P0 is the total pressure at the intake outlet; and P is the static pressure at the intake outlet.

3. The supersonic inlet wind tunnel test model considering the effect of leakage as described in claim 1, characterized in that, The discharge pipeline is equipped with a total pressure measuring rake and a wall static pressure measuring point for calculating the flow rate of the discharge pipeline.

4. A method for calculating relevant parameters of a supersonic inlet wind tunnel test model, characterized in that, Using the supersonic inlet wind tunnel test model considering the effect of leakage as described in any one of claims 1-3, the steady-state circumferential distortion index calculation method includes: The average total pressure at the intake duct outlet section is obtained by arithmetic averaging or flow averaging of the steady-state total pressure measurement values ​​obtained from the intake duct outlet total pressure measurement rake (4). ; Get the total incoming pressure ; Average total pressure at the inlet outlet section With the total pressure of the incoming flow Calculate the total pressure recovery coefficient σ at the intake duct outlet section; The intake duct outlet section is divided into multiple sector regions, and the average total pressure recovery coefficient of each sector region is calculated one by one. ; The angle corresponding to the j-th measuring rake The x-axis represents the average total pressure recovery coefficient of the sector region. Use the ordinate as the constructor. ; Based on functions The minimum average total pressure recovery coefficient is obtained by solving the average total pressure recovery coefficient for each low-pressure zone at the intake outlet section. ; Based on the minimum average total pressure recovery coefficient The steady-state circumferential distortion index is calculated using the total pressure recovery coefficient σ at the inlet outlet section. .

5. The method for calculating the steady-state circumferential distortion index of the supersonic inlet wind tunnel test model as described in claim 4, characterized in that, The average total pressure at the inlet outlet section is calculated using the arithmetic mean. The formula is: ； The number of rake walls for measuring the total pressure at the intake outlet (4) The number of steady-state total pressure measuring tubes for each rake wall.

6. The method for calculating the steady-state circumferential distortion index of the supersonic inlet wind tunnel test model as described in claim 5, characterized in that, The average total pressure at the inlet outlet section is calculated by averaging the flow rate. The formula is: ； ； For flow function, To measure the area of ​​a single surface element in a cross-section.

7. The method for calculating the steady-state circumferential distortion index of the supersonic inlet wind tunnel test model as described in claim 6, characterized in that, Average total pressure recovery coefficient The calculation formula is: ； is the total pressure recovery coefficient at the i-th measurement point in the j-th sector.

8. The method for calculating the steady-state circumferential distortion index of the supersonic inlet wind tunnel test model as described in claim 7, characterized in that, Minimum average total pressure recovery coefficient The calculation formula is: ； In the formula, and The starting and ending angles of the low-pressure zone corresponding to the smallest average total pressure recovery coefficient.

9. The method for calculating the steady-state circumferential distortion index of the supersonic inlet wind tunnel test model as described in claim 8, characterized in that, Steady-state circumferential distortion index The calculation formula is: 。 10. The method for calculating the steady-state circumferential distortion index of the supersonic inlet wind tunnel test model as described in claim 9, characterized in that, Turbulence The calculation formula is: ； in: Let J be the turbulence intensity of the j-th sector. ； ； in, This is the average dynamic total pressure. The dynamic total pressure is the j-th dynamic measurement point at the intake duct outlet section.

11. The method for calculating the steady-state circumferential distortion index of the supersonic inlet wind tunnel test model as described in claim 10, characterized in that, The formula for calculating the total pressure distortion index W is: 。

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