A small discontinuous airflow flow control measuring device and measuring method

Abstract

The application provides a small-sized discontinuous airflow flow control measuring device and a measuring method, and belongs to the technical field of aviation aerodynamics. The purpose is to solve the problem that the traditional inlet duct wind tunnel test technology cannot meet the small flow measurement requirement of a secondary flow system, and the airflow flow control measuring device relying on a driving motor cannot be miniaturized due to the size limitation. In the application, the tail end of the top of an inlet duct model is connected with a supporting rod, the inlet duct model is connected with a wind tunnel wall through the supporting rod, a secondary flow collecting and rectifying device, an ultrathin flow measuring device and a linear flow control device are installed on the inlet duct model, the length of a screw sleeve in the linear flow control device is adjusted, the throttling area of a throttling cone and a cone barrel outlet is changed, and different aircraft secondary flow data are obtained. The application solves the problem that the traditional inlet duct wind tunnel test technology cannot meet the small flow measurement requirement of a secondary flow system, and the airflow flow control measuring device relying on a driving motor cannot be miniaturized due to the size limitation.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of aviation aerodynamics, and particularly relates to a small non-continuous airflow flow control measuring device and a measuring method. BACKGROUND

[0002] The secondary flow system of an aircraft inlet plays an important role in fully improving the aerodynamic performance of the inlet and ensuring its stable operation. The secondary flow of an aircraft in a wind tunnel test is often very small, and in special cases only accounts for about 1% of the main flow. The traditional inlet wind tunnel test technology cannot meet the test requirements of the secondary flow system. Due to the limitations of the measured pressure rake volume, a flowmeter cannot be formed into a small flow control measuring device by simply scaling down the model. Micro-flow measurement requires a very small flow measuring device. When the flow measuring device is scaled down to a certain extent, it will not be able to arrange the actuator motor. Therefore, the airflow flow control measuring device relying on the actuator motor cannot be applied to micro-flow measurement, and a new flow control measuring device needs to be developed.

[0003] In view of the above, there is an urgent need to design a small non-continuous airflow flow control measuring device and a measuring method to solve the problem that the traditional inlet wind tunnel test technology cannot meet the micro-flow measurement requirements of the secondary flow system, and the airflow flow control measuring device relying on the actuator motor cannot be miniaturized due to size limitations. SUMMARY

[0004] In the following, a brief summary of the application is given to provide a basic understanding of some aspects of the application. It should be understood that this summary is not an exhaustive overview of the application. It is not intended to identify key or important parts of the application, nor is it intended to limit the scope of the application. Its purpose is merely to give some concepts in a simplified form as a prelude to the more detailed description discussed later.

[0005] In view of the above, there is an urgent need to design a small non-continuous airflow flow control measuring device and a measuring method to solve the problem that the traditional inlet wind tunnel test technology cannot meet the micro-flow measurement requirements of the secondary flow system, and the airflow flow control measuring device relying on the actuator motor cannot be miniaturized due to size limitations.

[0006] Scheme one: a small non-continuous airflow flow control measuring device, comprising a wind tunnel wall, an inlet model, a secondary flow collection and rectification device, an ultra-thin flow measuring device, a linear flow control device and a support rod.

[0007] The top tail end of the inlet model is connected with the support rod, and the inlet model is connected with the wind tunnel wall through the support rod.

[0008] The bottom of the air inlet channel model is provided with a secondary flow inlet and a main flow inlet, and the air inlet channel model is internally provided with a secondary flow collection and rectification device and an air inlet channel; the secondary flow collection and rectification device comprises a secondary flow collection section and a honeycomb, the secondary flow collection section comprises a secondary flow collection cavity and a secondary flow collection pipe, one end of the secondary flow collection cavity is connected with the secondary flow inlet, the other end is connected with the outer wall of the cone barrel above the air inlet channel model through the secondary flow collection pipe, and the honeycomb is installed in the cone barrel;

[0009] The ultrathin flow measurement device is arranged in the middle part of the cone barrel and comprises a total pressure probe pipe, a static pressure hole, a static pressure pipe, a total pressure pipe and an ultrathin total pressure rake, the ultrathin total pressure rake is installed in the middle part of the cone barrel through the inner wall and the outer wall of the cone barrel, total pressure probe pipes are arranged in equal areas in a ring shape on each rake of the ultrathin total pressure rake, the total pressure probe pipes extend to the total pressure pipe along the grooves on the ultrathin total pressure rake and are connected with the total pressure pipe through the outer wall of the cone barrel, and the total pressure probe pipes are uniformly distributed with a plurality of static pressure holes in the circumferential direction of the wall surface of the cone barrel at the same station cross section, and the static pressure pipe is installed in the static pressure hole;

[0010] The linear flow control device is installed at the outlet of the cone barrel and comprises an adjusting screw, a screw sleeve and a throttling cone, the outlet of the cone barrel is uniformly distributed with screw holes in the circumferential direction, the outer wall of the throttling cone is provided with a throttling cone base, the throttling cone base is provided with a throttling cone base through hole, and the adjusting screw is sequentially screwed into the screw hole through the throttling cone base through hole and the screw sleeve and is fixed.

[0011] Further, the total pressure probe pipe and the static pressure pipe are stainless steel hollow capillary pipes with an outer diameter of 1 mm.

[0012] Further, the static pressure hole is a “T” shape.

[0013] Further, the rear end of the total pressure probe pipe is connected with a pressure acquisition system through a pressure measuring hose, and the pressure acquisition system is in communication connection with a computer.

[0014] Further, the ultrathin total pressure rake is provided with grooves on the surface.

[0015] Scheme two: a measurement method of a small non-continuous air flow control and measurement device, specifically comprising the following steps:

[0016] S1. Install the secondary flow collection and rectification device and the ultrathin flow measurement device: the honeycomb can effectively rectify the air flow, and the total and static pressures of the rectified air flow meet the requirements of the air inlet channel test flow measurement, and after the installation of the ultrathin flow measurement device, the whole cone barrel is air-tight and meets the requirements of the measurement test;

[0017] S2. Install the linear flow control device: by selecting different lengths of the screw sleeve, the throttling area of the throttling cone and the outlet of the cone barrel is adjusted, linear subdivision of flow regulation is realized, the throttling area is determined according to the initial estimated secondary flow, and the corresponding screw sleeve length is selected;

[0018] S3. A total of stainless steel hollow capillary tubes are connected to the rear end of the cone-shaped tubes. All pressure measuring hoses are connected to the pressure acquisition system. The pressure acquisition system converts the pressure value into a digital signal and transmits it to the data processing computer. During the test, after the wind tunnel establishes a stable flow field, the main flow rate of the inlet is adjusted to the position and held for 3 seconds. Then, the pressure acquisition system collects the pressure sensed by the total pressure probe and the static pressure orifice. The main flow rate of the inlet continues to be adjusted and held for 3 seconds. Then, the pressure acquisition system collects the pressure sensed by the total pressure probe and the static pressure orifice again. The above steps are repeated according to the test requirements. After all the data collection is completed, the secondary flow rate is calculated through data processing.

[0019] S4. Adjust the length of the screw sleeve in S2 to change the throttling area of ​​the throttling cone and the cone outlet. Repeat S3 to obtain the aircraft secondary flow rate data under different main and secondary flow operating conditions.

[0020] The present invention has the following advantages over the prior art:

[0021] 1. This invention can measure minute flow rates that current flow meters cannot measure, and can measure the secondary flow rate of 1% or less of the secondary / mainstream flow in the intake duct in a wind tunnel;

[0022] 2. This invention eliminates the risk of the electric actuator's connection line being blown off or becoming loose during wind tunnel blowing tests, as well as the inability to adjust the flow rate by moving the cone due to high aerodynamic resistance;

[0023] 3. This invention establishes a test procedure standard for small-scale discontinuous airflow control and measurement devices in wind tunnel tests. Attached Figure Description

[0024] 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:

[0025] Figure 1 This is a schematic diagram of a small, discontinuous airflow control and measurement device, with the arrow pointing in the direction of the incoming flow.

[0026] Figure 2 for Figure 1 Top view;

[0027] Figure 3 This is a longitudinal symmetrical cross-sectional view of the present invention, excluding the secondary flow gas collection pipe;

[0028] Figure 4 This is a transverse symmetrical cross-sectional view of the present invention, excluding the secondary flow gas collection pipe;

[0029] Figure 5A rear view of the present application except the secondary flow collector.

[0030] In the figure: 1-wind tunnel wall, 2-inlet model, 3-secondary flow inlet, 4-primary flow inlet, 5-secondary flow collection cavity, 6-secondary flow collector, 7-inlet, 8-inlet outlet, 9-cone barrel outer wall, 10-supporting rod, 11-cone barrel inner wall, 12-honeycomb, 13-total pressure probe, 14-static pressure hole, 15-static pressure tube, 16-total pressure tube, 17-ultra-thin total pressure rake, 18-screw hole, 19-adjusting screw, 20-screw sleeve, 21-throttle cone base through hole, 22-throttle cone base, 23-throttle cone. DETAILED DESCRIPTION

[0031] In order to make the technical solutions and advantages in the embodiments of the present application clearer, the exemplary embodiments of the present application are 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 application, and not all the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0032] Embodiment 1, Reference Figures 1-5 This embodiment is a small non-continuous air flow control and measurement device, which comprises a wind tunnel wall 1, an inlet model 2, a secondary flow collection and rectification device, an ultra-thin flow measurement device, a linear flow control device and a supporting rod 10.

[0033] The top tail end of the inlet model 2 is connected with the supporting rod 10, and the inlet model 2 is connected with the wind tunnel wall 1 through the supporting rod 10.

[0034] The inlet model 2 is provided with a secondary flow collection and rectification device and an inlet 7, and the bottom of the inlet model 2 is provided with a secondary flow inlet 3 and a primary flow inlet 4. The secondary flow collection and rectification device comprises a secondary flow collection section and a honeycomb 12. The secondary flow collection section comprises a secondary flow collection cavity 5 and a secondary flow collector 6. One end of the secondary flow collection cavity 5 is connected with the secondary flow inlet 3, and the other end is connected with the cone barrel outer wall 9 above the inlet model 2 through the secondary flow collector 6. The honeycomb 12 is installed inside the cone barrel to rectify the airflow. One end of the inlet 7 is connected with the primary flow inlet 4, and the other end is connected with the inlet outlet 8 at the end of the inlet model 2.

[0035] The ultra-thin flow measurement device is located in the middle of the cone and includes a total pressure probe 13, static pressure holes 14, static pressure pipes 15, total pressure pipes 16, and an ultra-thin total pressure rake 17. The ultra-thin total pressure rake 17 passes through the inner wall 11 and the outer wall 9 of the cone and is installed in the middle of the cone. The total pressure probe 13 is arranged in a ring with equal area on each rake of the ultra-thin total pressure rake 17. The total pressure probe 13 extends along the groove on the ultra-thin total pressure rake 17 to the outer wall 9 of the cone and is connected to the total pressure pipe 16. Several static pressure holes 14 are evenly distributed around the circumference of the cone wall at the same station section of the inlet of the total pressure probe 13. Static pressure pipes 15 are installed in the static pressure holes 14.

[0036] The linear flow control device is installed at the outlet of the cone and includes an adjusting screw 19, a screw sleeve 20 and a throttling cone 23. Screw holes 18 are evenly distributed around the cone outlet. A throttling cone base 22 is provided on the outer wall of the throttling cone 23. A throttling cone base through hole 21 is provided on the throttling cone base 22. The adjusting screw 19 passes through the throttling cone base through hole 21 and the screw sleeve 20 in sequence and is screwed into the screw hole 18 for fixation.

[0037] Furthermore, the total pressure probe 13 and the static pressure probe 15 are stainless steel hollow capillary tubes with an outer diameter of 1 mm.

[0038] Furthermore, the static pressure hole 14 is T-shaped.

[0039] Furthermore, the rear end of the total pressure probe 13 is connected to the pressure acquisition system via a pressure measuring hose. The pressure acquisition system is connected to a computer and converts the pressure value into a digital signal, which is then transmitted to the data processing computer.

[0040] Furthermore, the surface of the ultra-thin total pressure rake 17 is provided with grooves.

[0041] Example 2, Reference Figures 1-5 This embodiment describes a measurement method for a small, discontinuous airflow control and measurement device, which specifically includes the following steps:

[0042] S1. Install secondary flow collection and rectification device and ultra-thin flow measurement device: the honeycomb unit 12 can effectively rectify the airflow. After rectification, the total and static pressure of the airflow meet the test flow measurement requirements of the air inlet 7. After the ultra-thin flow measurement device is installed, the cone does not leak air as a whole and meets the pressure test requirements.

[0043] The honeycomb device 12 is installed to the inlet of the conical barrel inner wall 11, and is fixed by screwing with glue-dipped screws; four ultra-thin total pressure rakes 17 are installed to the middle of the conical barrel interior to measure the total pressure of the airflow, five total pressure probes 13 are arranged on each rake according to equal area rings, totaling 20 total pressure probes 13, the static pressure of the airflow is measured through four static pressure holes 14 evenly distributed on the conical barrel wall surface at the same station as the inlets of the total pressure probes 13, the 20 total pressure probes extend from the conical barrel interior to the conical barrel outer wall surface through the grooves of the ultra-thin total pressure rakes 17, the grooves of the ultra-thin total pressure rakes 17 are leveled by smearing 302AB glue, the bases of the ultra-thin total pressure rakes 17 are fixed to the conical barrel outer wall 9 by screwing, the contact surface is sealed with rubber rings, four static pressure tubes 15 are inserted into the four static pressure holes 14 pre-drilled on the conical barrel wall surface, and are fixed by smearing 302AB glue; after the above steps are completed, blocking plates are installed at both ends of the conical barrel, high pressure is punched into the interior, and the conical barrel is confirmed to be qualified if the high pressure of 200 KPa in the barrel is maintained for 3 seconds without decreasing;

[0044] S2. Installing a linear flow control device: by selecting different lengths of the screw sleeve 20, the throttling area of the throttling cone 23 and the outlet of the conical barrel is adjusted, linear subdivision of flow regulation is achieved, the throttling area is determined according to the initial estimated secondary flow rate, and the corresponding length of the screw sleeve 20 is selected;

[0045] A number of groups of screw sleeves 20 need to be pre-processed according to actual test requirements before the test, each group of screw sleeves 20 has the same parameters, a group of screw sleeves 20 is selected, the adjusting screw 19 is passed through the through hole 21 of the throttling cone base, then is passed through the screw sleeve 20, and is screwed into the screw holes 18 evenly distributed on the outlet of the conical barrel to be fixed, thereby forming a flow passage cross section to control the airflow; the screw sleeve 20 has a linear relationship with the throttling area, the throttling area of the throttling cone 23 and the outlet of the conical barrel is adjusted by using different lengths of the screw sleeve 20, and subdivision of flow regulation is achieved;

[0046] S3. The rear ends of a total of 24 stainless steel hollow capillary tubes on the conical barrel outer wall 9 are connected to pressure measuring hoses, all the pressure measuring hoses are connected to a pressure acquisition system, the pressure acquisition system converts the pressure values into digital signals and transmits them to a data processing computer; during the test, after the wind tunnel establishes a stable flow field, the main flow of the inlet duct 7 is adjusted to the position and stays for 3 seconds, then the pressure acquisition system acquires the pressures sensed by the total pressure probes 13 and the static pressure holes 14, the main flow of the inlet duct 7 continues to be adjusted, stays at the position for 3 seconds, then the pressure acquisition system again acquires the pressures sensed by the total pressure probes 13 and the static pressure holes 14, the above steps are repeated according to test requirements, after all the acquisition is completed, the secondary flow rate is obtained through data processing and calculation;

[0047] S4. The length of the screw sleeve 20 in S2 is adjusted, the throttling area of the throttling cone 23 and the outlet of the conical barrel is changed, S3 is repeated, and the secondary flow rate data of the airplane under different main and secondary flow working conditions are obtained.

[0048] The present application can measure the tiny flow which cannot be measured by the current flow meter, and realize the measurement of the sub-flow flow ratio of 1% and below of the inlet duct sub-flow / main flow in the wind tunnel; meanwhile, the present application does not have the electric actuator device, and eliminates the risk that the electric actuator adjustment system connection line is blown off, virtually connected or cannot walk the cone to adjust the flow due to the large aerodynamic resistance in the process of the wind tunnel blowing test.

[0049] The present application formulates the test process standard of the small non-continuous air flow control and measurement device in the wind tunnel test.

[0050] Although the present application is described according to a limited number of embodiments, those skilled in the art, with the benefit of the above description, will appreciate that other embodiments are conceivable within the scope of the present application described herein. Furthermore, it should be noted that the language used in the specification is principally selected for readability and instructional purposes and can not have been selected to delineate or circumscribe the inventive subject matter. Accordingly, it is to be understood that numerous modifications and variations of the present application are possible in light of the above teachings and within the scope of the appended claims, which are to be interpreted in the broadest reasonable manner possible. The disclosure of the present application is illustrative and not restrictive, the scope of the present application being indicated by the appended claims.

Claims

1. A small, discontinuous airflow control and measurement device, characterized in that, It includes the wind tunnel wall (1), the air intake model (2), the secondary flow collection and rectification device, the ultra-thin flow measurement device, the linear flow control device, and the support rod (10). The top and tail end of the air intake model (2) are connected to the support rod (10), and the air intake model (2) is connected to the wind tunnel wall (1) through the support rod (10); The bottom of the intake model (2) is provided with a secondary flow inlet (3) and a main flow inlet (4). The intake model (2) is provided with a secondary flow collection and rectification device and an intake duct (7). The secondary flow collection and rectification device includes a secondary flow collection section and a honeycomb device (12). The secondary flow collection section includes a secondary flow collection chamber (5) and a secondary flow collection pipe (6). One end of the secondary flow collection chamber (5) is connected to the secondary flow inlet (3), and the other end is connected to the outer wall (9) of the cone above the intake model (2) through the secondary flow collection pipe (6). The honeycomb device (12) is installed inside the cone. One end of the intake duct (7) is connected to the main flow inlet (4), and the other end is connected to the intake duct outlet (8) at the end of the intake model (2). The ultra-thin flow measurement device is located in the middle of the cone and includes a total pressure probe (13), a static pressure hole (14), a static pressure pipe (15), a total pressure pipe (16), and an ultra-thin total pressure rake (17). The ultra-thin total pressure rake (17) passes through the inner wall (11) and the outer wall (9) of the cone and is installed in the middle of the cone. The total pressure probe (13) is arranged in a ring with equal area on each rake of the ultra-thin total pressure rake (17). The total pressure probe (13) extends along the groove on the ultra-thin total pressure rake (17) to the outer wall (9) of the cone and is connected to the total pressure pipe (16). Several static pressure holes (14) are evenly distributed around the cone wall at the same station section at the inlet of the total pressure probe (13). Static pressure pipes (15) are installed in the static pressure holes (14). The linear flow control device is installed at the outlet of the cone and includes an adjusting screw (19), a screw sleeve (20) and a throttling cone (23). Screw holes (18) are evenly distributed around the outlet of the cone. A throttling cone base (22) is provided on the outer wall of the throttling cone (23). A throttling cone base through hole (21) is provided on the throttling cone base (22). The adjusting screw (19) passes through the throttling cone base through hole (21) and the screw sleeve (20) in sequence and is screwed into the screw hole (18) for fixation.

2. The small discontinuous airflow control and measurement device according to claim 1, characterized in that, The total pressure probe (13) and static pressure probe (15) are stainless steel hollow capillary tubes with an outer diameter of 1 mm.

3. The small discontinuous airflow control and measurement device according to claim 2, characterized in that, The static pressure hole (14) is T-shaped.

4. The small discontinuous airflow flow control and measurement device according to claim 3, characterized in that, The rear end of the total pressure probe (13) is connected to the pressure acquisition system via a pressure measuring hose, and the pressure acquisition system is connected to a computer for communication.

5. The small discontinuous airflow control and measurement device according to claim 1, characterized in that, The surface of the ultra-thin total pressure rake (17) is provided with grooves.

6. The measurement method of the small discontinuous airflow control and measurement device according to claim 4 specifically includes the following steps: S1. Install secondary flow collection and rectification device and ultra-thin flow measurement device: the honeycomb unit (12) can effectively rectify the airflow. After rectification, the total and static pressure of the airflow meet the test flow measurement requirements of the air inlet (7). After the ultra-thin flow measurement device is installed, the cone does not leak air and meets the pressure test requirements. S2. Install a linear flow control device: By selecting different lengths of the screw sleeve (20), adjust the throttling area of ​​the throttling cone (23) and the cone outlet to achieve linear subdivision of flow regulation. Determine the throttling area based on the initial estimated secondary flow rate and select the corresponding screw sleeve (20) length. S3. A total of 24 stainless steel hollow capillary tubes on the outer wall (9) of the cone are connected to pressure measuring hoses at the rear end. All pressure measuring hoses are connected to the pressure acquisition system. The pressure acquisition system converts the pressure value into a digital signal and transmits it to the data processing computer. During the test, after the wind tunnel establishes a stable flow field, the main flow of the air inlet (7) is adjusted to the position and stays for 3 seconds. The pressure acquisition system collects the pressure felt by the total pressure probe (13) and the static pressure hole (14). The main flow of the air inlet (7) continues to be adjusted. After staying in the position for 3 seconds, the pressure acquisition system collects the pressure felt by the total pressure probe (13) and the static pressure hole (14) again. The above steps are repeated according to the test requirements. After all the collection is completed, the secondary flow rate is calculated by data processing. S4. Adjust the length of the screw sleeve (20) in S2 to change the throttling area of ​​the throttling cone (23) and the cone outlet. Repeat S3 to obtain the aircraft secondary flow data under different main and secondary flow working conditions.

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