Aircraft model head shock tunnel wall reflected wave blocking device and method

Abstract

The invention discloses an aircraft model head shock tunnel wall reflected wave blocking device and method, and relates to the field of aircraft force measurement wind tunnel tests. A reflected shock wave blocking plate is installed at the downstream position of a flow field near a reflection point, a reflection path of head shock waves is cut off, reflected waves of the head shock waves can be effectively restrained and dissipated between the reflected shock wave blocking plate and a wind tunnel wall, and the risk that the reflected waves of the head shock waves hit the tail of a model is eliminated; reflected waves of head shock waves can be suppressed without interfering a wind tunnel flow field, accuracy of test results is guaranteed, the reflected shock wave arresting device has a position adjusting function in the up-down direction and the front-back direction, most test requirements can be met, an original tunnel test scheme does not need to be changed during use, and the test efficiency is improved. The device is simple, easy to design, machine and implement, easy to operate, suitable for multiple scenes and high in economical efficiency.

Description

Technical Field

[0001] The invention relates to the field of aircraft force measurement wind tunnel tests, and in particular to an aircraft model head shock wave tunnel wall reflection wave arresting device and method. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0003] Wind tunnel tests are an important and reliable source of data for obtaining aerodynamic characteristics of aerodynamic shapes. When conducting wind tunnel tests on the aerodynamic characteristics of aircraft in a supersonic wind tunnel, the airflow at the head of the model is strongly compressed to produce a head shock wave. The head shock wave has a certain inclination angle. When the inclined head shock wave develops to the upper and lower walls of the wind tunnel, a reflection phenomenon similar to the reflection of light will occur. If the test Mach number (M number) is low supersonic, the inclination angle of the head shock wave is large, and the reflected shock wave may hit the rear fuselage or tail rudder of the model, seriously interfering with the test results. Therefore, the model must be kept away from the influence of the reflected wave of the head shock wave in order to obtain reliable low supersonic test results.

[0004] In traditional supersonic wind tunnel tests, the length of the model is generally restricted to a certain extent, so that the reflected head shock wave hits the outside of the tail of the model, so as to obtain test results without shock wave interference. However, due to the limitation of model size, this method leads to a small internal space, and it is difficult to arrange the test balance and various sensor modules inside the model, which limits the expansion of the test content, especially for models with high slenderness, such as missiles, rockets, and supersonic passenger aircraft. On the other hand, for tests with a large range of test M numbers, interference from the reflected head shock wave will only occur in low supersonic tests. If the model size is limited for this reason, it will limit the content of all subsequent high M number tests, and the cost will be unbearable.

[0005] Therefore, it is necessary to propose a simple, easy-to-operate and widely applicable reflected wave arresting method and device to address the interference problem of shock wave reflected waves in low supersonic wind tunnel test heads. Summary of the invention

[0006] The purpose of the present invention is to provide a device and method for arresting the reflected wave of the shock wave of the aircraft model head on the tunnel wall, so as to solve the problem that during the current low supersonic wind tunnel test of the aircraft, the shock wave angle is relatively large, and the oblique shock wave of the head of the test model is easily reflected by the upper and lower walls of the wind tunnel and hits the tail of the model, thereby affecting the model force measurement test results.

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

[0008] A device for arresting reflected waves from the head shock wave wall of an aircraft model comprises: a reflected shock wave arrester, an arrester support blade and a support blade position adjustment device; one end of the arrester support blade is connected to the reflected shock wave arrester, and the other end passes through the wind tunnel wall and is fixedly connected to the wind tunnel wall through the support blade position adjustment device; the support blade position adjustment device can adjust the position of the arrester support blade, thereby adjusting the position of the reflected shock wave arrester, ensuring that the head shock wave reflected wave can be reflected back and forth in the channel between the reflected shock wave arrester and the wind tunnel wall until the energy is exhausted.

[0009] Furthermore, in the top view of the reflective shock wave arrester, the leading edge is elliptical and the trailing edge is square.

[0010] Furthermore, the reflected shock wave arrester is a flat plate in the shape of a supersonic airfoil in the flow direction section, and its front and rear edges are both wedge-shaped, wherein the leading edge wedge angle is smaller than the model head wedge angle.

[0011] Furthermore, the baffle supporting blade is rectangular as a whole, one end of which is connected to the reflected shock wave baffle, and the other end passes through the inner side of the wind tunnel wall to the outside of the wall. The cross-section is a supersonic airfoil shape, and the leading and trailing edges are both wedge-shaped.

[0012] Furthermore, the cross-sectional length of the barrier plate supporting blade is less than 1 / 2 times the length of the reflected shock wave barrier plate.

[0013] Furthermore, the supporting blade position adjusting device can adjust the position of the blocking plate supporting blade in both the front-rear and upper-lower directions.

[0014] Furthermore, it also includes: a rectifying filler, which is used to fill the gap between the baffle supporting blades and the wind tunnel wall.

[0015] A method for arresting reflected waves from shock waves of a model aircraft head and a hole wall, based on the above-mentioned device for arresting reflected waves from shock waves of a model aircraft head and a hole wall, comprises:

[0016] Step S1: Conduct a low supersonic wind tunnel test to blow air to determine whether the reflected wave of the head shock wave hits the tail of the model within the test angle of attack range; if so, proceed to step S2; if not, continue the test;

[0017] Step S2: Determine the reflection points of the head shock wave on the upper and lower walls of the actual wind tunnel, and mark them on the walls of the wind tunnel;

[0018] Step S3: installing a reflected wave arresting device at a position downstream of the mark, and adjusting the position of the reflected shock wave arresting plate by the supporting blade position adjusting device to ensure that the head shock wave reflected wave can be reflected back and forth in the channel between the reflected shock wave arresting plate and the wind tunnel wall until the energy is exhausted;

[0019] Step S4: Repeat step S1 to determine again whether the reflected wave of the head shock wave hits the tail of the model within the test angle of attack range; if so, return to step S1 based on the test data of this test, and adjust the position of the reflected wave arrester until the phenomenon no longer occurs; if not, the test data of this test can be used directly, and the low supersonic test content is carried out in this state.

[0020] Furthermore, the step S1 comprises:

[0021] Use the flow display method to observe whether the reflected wave of the head shock wave hits the tail of the model within the test angle of attack range. If it is not possible to observe through the flow display method, you can also check the model pitch moment test results to see whether there is a sudden jump in the small angle of attack range. If this phenomenon occurs, it can be inferred that the reflected wave of the head shock wave has hit the tail of the model in the test.

[0022] Furthermore, the step S2 comprises:

[0023] The image of the head shock wave or the reflected wave of the head shock wave is observed by the schlieren method, the angle of the shock wave line is measured in the image, and the reflection points on the upper and lower walls of the actual wind tunnel are inferred according to the position of the nose point, and marked on the wind tunnel wall;

[0024] If the head shock wave cannot be directly observed in the test in step S1, and the head of the model is a regular wedge-shaped wedge shape, the shock wave angle can be calculated by iterative calculation according to the theoretical formula or table lookup method, and the position of the reflection point can be marked.

[0025] If the shock wave cannot be directly observed in the test in step S1, and the model head has an irregular shape, find the center position between the tip of the nose and the farthest point of the tail in the length direction of the model, and project it vertically on the upper and lower walls of the wind tunnel. The projection position is the position of the reflection point and mark it.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention installs a reflected shock wave arrester at a downstream position of the flow field near the reflection point to cut off the reflection path of the head shock wave, which can effectively constrain and dissipate the reflected wave of the head shock wave between the reflected shock wave arrester and the wind tunnel wall, eliminating the risk of the reflected wave of the head shock wave hitting the tail of the model; the reflected shock wave arrester in the present invention has position adjustment functions in both the up and down and front and back directions, and can adapt to most test requirements; the method and device in the present invention do not need to change the original wind tunnel test plan when used, the device is simple, easy to design, process and realize, easy to operate, applicable to many scenarios, and highly economical. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a diagram showing the principle and installation location of a device for arresting reflected waves from the shock wave tunnel wall of an aircraft model head;

[0029] Figure 2 It is a front view of a device for arresting reflected waves from the shock wave tunnel wall of an aircraft model head;

[0030] Figure 3 It is a top view of a device for arresting reflected waves from the shock wave tunnel wall of an aircraft model head;

[0031] Figure 4 The present invention is a flow chart of a method for arresting reflected waves from the shock wave tunnel wall of an aircraft model head.

[0032] Figure numerals: 1-wind tunnel wall, 2-supersonic wind tunnel test section flow field, 3-model, 4-test support, 5-blocking plate supporting blade, 6-support blade position adjustment device, 7-reflected shock wave blocker, 8-channel, 9-head shock wave reflected wave, 10-model head shock wave, 11-reflection point, 12-shock wave blocker interference wave. DETAILED DESCRIPTION

[0033] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0034] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0035] Embodiment 1

[0036] See also Figure 1-3 , an aircraft model head shock wave tunnel wall reflection wave arresting device, specifically comprising the following structure:

[0037] A reflected shock wave arrester, an arrester support blade and a support blade position adjustment device; one end of the arrester support blade is connected to the reflected shock wave arrester, and the other end passes through the wind tunnel wall and is fixedly connected to the wind tunnel wall through the support blade position adjustment device; the support blade position adjustment device can adjust the position of the arrester support blade, thereby adjusting the position of the reflected shock wave arrester to ensure that the head shock wave reflected wave can be reflected back and forth in the channel between the reflected shock wave arrester and the wind tunnel wall until the energy is exhausted;

[0038] Among them, the supersonic wind tunnel is a large-scale device for generating high-speed airflow for conducting aerodynamic characteristic tests on aircraft;

[0039] The wind tunnel wall is the wall surface of the constrained flow field area that is closed up, down, left, and right at the model installation location.

[0040] In this embodiment, specifically, in the top view of the reflected shock arrester, the leading edge is elliptical and the trailing edge is square; the reflected shock arrester is a flat plate in the shape of a supersonic airfoil along the flow direction section, and the leading and trailing edges of the cross section are both wedge-shaped, wherein the leading edge wedge angle is smaller than the model head wedge angle; it should be noted that the width of the reflected shock arrester is roughly equivalent to the width of the rear body of the model, and the length of the reflected shock arrester is equivalent to 1 / 4 of the length of the model; in order to ensure that the oblique shock wave at the head of the reflected shock arrester does not hit the model, the leading edge wedge angle of the flat plate cross section should be as small as possible, and especially should be smaller than the model head wedge angle.

[0041] In the present embodiment, specifically, the barrier plate supporting blade is rectangular as a whole, one end of which is connected to the reflected shock wave arrester, and the other end of which passes through the inner side of the wind tunnel wall (the test flow field side) to the outside of the tunnel wall, and the cross-section is a supersonic airfoil shape, and the leading and trailing edges are both wedge-shaped; the cross-sectional length of the barrier plate supporting blade is less than 1 / 2 times the length of the reflected shock wave arrester; it should be noted that, depending on the structural strength requirements of the reflected wave arrester device, the barrier plate supporting blade may be one piece or may be several pieces.

[0042] In this embodiment, specifically, the supporting blade position adjusting device can adjust the position of the blocking plate supporting blade in two directions, front and rear and up and down.

[0043] In this embodiment, specifically, it also includes: a rectifying filler, which is used to fill the gap between the baffle supporting blades and the wind tunnel wall and ensure the sealing of the tunnel wall; preferably, the rectifying filler is a tunnel wall gap compensation putty.

[0044] See also Figure 4 A method for arresting reflected waves from shock wave tunnel wall of an aircraft model head. Based on the above-mentioned device for arresting reflected waves from shock wave tunnel wall of an aircraft model head, firstly, the original wind tunnel test plan prepares the test wind tunnel, model and other conditions; then the following steps are carried out:

[0045] Step S1: Conduct a low supersonic wind tunnel test to blow air to determine whether the reflected wave of the head shock wave hits the tail of the model within the test angle of attack range; if so, proceed to step S2; if not, continue the test;

[0046] Step S2: Determine the reflection points of the head shock wave on the upper and lower walls of the actual wind tunnel, and mark them on the walls of the wind tunnel;

[0047] Step S3: installing a reflected wave arresting device at a position downstream of the mark, and adjusting the position of the reflected shock wave arresting plate by the supporting blade position adjusting device to ensure that the head shock wave reflected wave can be reflected back and forth in the channel between the reflected shock wave arresting plate and the wind tunnel wall until the energy is exhausted;

[0048] It should be noted that in order to avoid air congestion, the position of the reflected shock wave arrester cannot be too close to the wind tunnel wall. The distance varies depending on the wind tunnel scale. It is safer when the distance is greater than the diameter of the test model support rod. When the test angle of attack changes, the shock wave angle and the position of the marking point will also change slightly. To ensure the applicability of this method, at least the minimum and maximum angles of attack of the test when the reflected wave hits the tail of the model should be selected for evaluation to determine the moving range of the marking point and the changing area of ​​the shock wave reflection path, and the final installation position of the arrester is determined accordingly.

[0049] Step S4: repeat step S1, and judge again whether the reflected wave of the head shock wave hits the tail of the model within the test angle of attack range; if so, return to step S1 and continue to execute based on the test data of this test, and adjust the position of the reflected wave arresting device accordingly until the phenomenon no longer occurs; if not, the test data of this test can be used directly, and the low supersonic test content is carried out in this state; it should be noted that in the case of higher M number tests, the reflected wave of the head shock wave generally does not hit the tail of the model, and the reflected wave arresting device installed in this method should be removed, and the installation interface of the device on the wind tunnel wall should be filled before the subsequent tests can be carried out normally.

[0050] In this embodiment, specifically, step S1 includes:

[0051] Use flow display methods such as schlieren to observe whether the reflected wave of the head shock wave hits the tail of the model within the test angle of attack range;

[0052] If it is not possible to observe by flow display method, you can also check the model pitch moment test results to see if there is a sudden jump in the small angle of attack range. If this phenomenon occurs, it can be inferred that the head shock wave reflection wave has hit the tail of the model in the test;

[0053] If the reflected wave of the head shock wave does not hit the tail of the model under the condition of the minimum supersonic speed M number required for the test, the test will continue as originally planned; if this phenomenon occurs, the angle of attack sequence of the model when the collision occurs will be recorded, and the method will continue to be implemented according to the following steps.

[0054] In this embodiment, specifically, step S2 includes:

[0055] The image of the head shock wave or the reflected wave of the head shock wave is observed by the schlieren method, the angle of the shock wave line is measured in the image, and the reflection points on the upper and lower walls of the actual wind tunnel are inferred according to the position of the nose point, and marked on the wind tunnel wall;

[0056] If the head shock wave cannot be directly observed in the test in step S1, and the head of the model is a regular wedge-shaped wedge shape, the shock wave angle can be calculated by iterative calculation according to the theoretical formula or table lookup method, and the position of the reflection point can be marked.

[0057] If the shock wave cannot be directly observed in the test in step S1, and the model head has an irregular shape, find the center position between the tip of the nose and the farthest point of the tail in the length direction of the model, and project it vertically on the upper and lower walls of the wind tunnel. The projection position is the position of the reflection point and mark it.

[0058] It should be noted that in the above method, if the upper and lower walls of the wind tunnel are convenient for installing shock wave arresters, the test can be carried out by rotating the model 90 degrees and installing reflected wave arresters on the left and right walls of the wind tunnel according to the above method.

[0059] It should be noted that in the above method, if the reflected waves of the model head shock wave on the left and right side walls of the wind tunnel hit the model side rear fuselage, affecting the lateral aerodynamic test results, the above method can also be imitated to install shock wave arresting devices on the left and right walls of the wind tunnel according to the above method.

[0060] It should be noted that the shock wave line for measuring the angle in step S2 can be the head shock wave or the reflected shock wave of the head shock wave. If the complete shock wave path cannot be observed, it can also be a partial shock wave. The angle of the head shock wave can be inferred based on the principle of incident wave and reflected wave.

[0061] Embodiment 2

[0062] See also Figure 1-4 The test scheme of this embodiment is aimed at a wind tunnel test of a supersonic aircraft. When the model is at a low supersonic speed M=1.5, the reflected wave of the nose shock wave will hit the rudder surface at the tail of the model, causing a large jump in the pitch moment test results. It is necessary to suppress the reflection of the nose shock wave to obtain accurate test results. In view of the above problems, the specific operation process of this embodiment includes the following steps:

[0063] Step a: prepare the test supersonic wind tunnel test section flow field 2, model 3, experimental support 4 and other conditions according to the original wind tunnel test plan;

[0064] Step b: Conduct a low supersonic wind tunnel test and observe whether the head shock wave reflection wave 9 hits the tail of the model within the test angle of attack range by using flow display methods such as schlieren. In this example, the head shock wave 10 and the head shock wave reflection wave 9 of the model can be captured by flow display methods such as schlieren. Obviously, the head shock wave reflection wave 9 has hit the tail of the model;

[0065] Step c: If the image of the model head shock wave 10 or the head shock wave reflection wave 9 can be observed by the schlieren method in the experiment in step b, the angle of the shock wave line can be measured in the image, and the reflection points on the upper and lower walls of the actual wind tunnel can be inferred according to the position of the nose point, and marked on the wall. For example, in this example, marks are made at the reflection points 11 on the upper and lower walls of the inferred wind tunnel;

[0066] Step d: Install a reflected wave arresting device at a position downstream of the upper and lower wall mark points, and adjust the position of the arresting plate supporting blade 5 up, down, left and right through the supporting blade position adjusting device 6 according to the reflected wave path observed or inferred in step c, so as to adjust the position of the reflected shock wave arresting plate 7 to ensure that the head shock wave reflected wave 9 is reflected back and forth in the channel 8 between the reflected shock wave arresting plate 7 and the wind tunnel wall 1 until the energy is exhausted; in this example, the head shock wave reflected wave 9 is confined in the channel 8 after the reflected wave arresting device is installed.

[0067] Step e: Repeat the low supersonic test under the same conditions as in step b, and confirm whether the head shock wave reflection wave 9 within the test angle of attack range is blocked by the schlieren method or the test results, and whether the head shock wave generated by the reflected shock wave arresting device avoids the tail of the model;

[0068] If the reflected shock wave is not observed to hit the tail of the model, the test data can be used directly, and the low supersonic test content can be carried out in this state. In the case of higher M number tests, the head shock wave reflection wave 9 generally does not hit the tail of the model 3. The reflected shock wave arresting device installed in this method should be removed, and the installation interface of this device on the cave wall should be filled before the subsequent tests can be carried out normally.

[0069] If it is still found that the head shock wave reflected wave 9 hits the tail of the model 3, the result of this time should be used as a basis to return to step b and continue to adjust the position of the reflected shock wave arrester until the phenomenon no longer occurs.

[0070] The above-mentioned embodiments only express the specific implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the protection scope of the present application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the technical solution concept of the present application, and these all belong to the protection scope of the present application.

[0071] This background section is provided to generally present the context of the invention, and the work of the presently named inventors, the work to the extent described in this background section, and aspects of this section that did not constitute prior art at the time of application are neither explicitly nor implicitly admitted to be prior art to the present invention.

Claims

1. An aircraft model head shock wave tunnel wall reflection wave arresting device, characterized in that: include: Reflective shock wave arrester, arrester support blades and support blade position adjustment device; One end of the baffle support blade is connected to the reflected shock wave baffle, and the other end passes through the wind tunnel wall and is fixedly connected to the wind tunnel wall through a support blade position adjustment device; the support blade position adjustment device can adjust the position of the baffle support blade, thereby adjusting the position of the reflected shock wave baffle to ensure that the head shock wave reflected wave can be reflected back and forth in the channel between the reflected shock wave baffle and the wind tunnel wall until the energy is exhausted.

2. The aircraft model head shock wave tunnel wall reflection wave arresting device according to claim 1, characterized in that: In the top view of the reflective shock wave arrester, the leading edge is elliptical and the trailing edge is square.

3. The aircraft model head shock wave tunnel wall reflection wave arresting device according to claim 2, characterized in that: The reflected shock wave arrester is a flat plate in the shape of a supersonic airfoil in the flow direction section, and its front and rear edges are both wedge-shaped, wherein the leading edge wedge angle is smaller than the model head wedge angle.

4. The aircraft model head shock wave tunnel wall reflection wave arresting device according to claim 1, characterized in that: The blocker support blade is rectangular as a whole, one end of which is connected to the reflected shock wave blocker, and the other end passes through the inner side of the wind tunnel wall to the outside of the wall. The cross-section is a supersonic airfoil shape, and the leading and trailing edges are both wedge-shaped.

5. The aircraft model head shock wave tunnel wall reflection wave arresting device according to claim 4, characterized in that: The cross-sectional length of the barrier plate supporting blade is less than 1 / 2 times the length of the reflected shock wave barrier plate.

6. The aircraft model head shock wave tunnel wall reflection wave arresting device according to claim 1, characterized in that: The support blade position adjustment device can adjust the position of the blocking plate support blade in two directions: front and rear and up and down.

7. The aircraft model head shock wave tunnel wall reflection wave arresting device according to claim 1, characterized in that: Also includes: A flow-rectifying filler is used to fill the gap between the baffle supporting blades and the wind tunnel wall.

8. A method for arresting reflected waves from the shock wave tunnel wall of an aircraft model head, characterized in that: An aircraft model head shock wave tunnel wall reflection wave arresting device according to any one of claims 1 to 7, comprising: Step S1: Conduct a low supersonic wind tunnel test to blow air to determine whether the reflected wave of the head shock wave hits the tail of the model within the test angle of attack range; if so, proceed to step S2; if not, continue the test; Step S2: Determine the reflection points of the head shock wave on the upper and lower walls of the actual wind tunnel, and mark them on the walls of the wind tunnel; Step S3: installing a reflected wave arresting device at a position downstream of the mark, and adjusting the position of the reflected shock wave arresting plate by the supporting blade position adjusting device to ensure that the head shock wave reflected wave can be reflected back and forth in the channel between the reflected shock wave arresting plate and the wind tunnel wall until the energy is exhausted; Step S4: Repeat step S1 to determine again whether the reflected wave of the head shock wave hits the tail of the model within the test angle of attack range; if so, return to step S1 based on the test data of this test, and adjust the position of the reflected wave arrester until the phenomenon no longer occurs; if not, the test data of this test can be used directly, and the low supersonic test content is carried out in this state.

9. A method for arresting reflected waves from a shock wave tunnel wall of an aircraft model head according to claim 8, characterized in that: The step S1 comprises: Use the flow display method to observe whether the reflected wave of the head shock wave hits the tail of the model within the test angle of attack range. If it is not possible to observe through the flow display method, you can also check the model pitch moment test results to see whether there is a sudden jump in the small angle of attack range. If this phenomenon occurs, it can be inferred that the reflected wave of the head shock wave has hit the tail of the model in the test.

10. The method for arresting reflected waves from the shock wave tunnel wall of an aircraft model head according to claim 8, characterized in that: The step S2 comprises: The image of the head shock wave or the reflected wave of the head shock wave is observed by the schlieren method, the angle of the shock wave line is measured in the image, and the reflection points on the upper and lower walls of the actual wind tunnel are inferred according to the position of the nose point, and marked on the wind tunnel wall; If the head shock wave cannot be directly observed in the test in step S1, and the head of the model is a regular wedge-shaped wedge shape, the shock wave angle can be calculated by iterative calculation according to the theoretical formula or table lookup method, and the position of the reflection point can be marked; If the shock wave cannot be directly observed in the test in step S1, and the model head has an irregular shape, find the center position between the tip of the nose and the farthest point of the tail in the length direction of the model, and project it vertically on the upper and lower walls of the wind tunnel. The projection position is the position of the reflection point and mark it.

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