Flexible Measuring Device for Strut Interference in the Open High Angle-of-Attack Test System

Abstract

A flexible measuring device for bracket interference in an open large angle of attack test system of the present invention belongs to the field of aircraft tests. It includes a balance, a main support unit, a mirror support unit and a flexible adjustment unit. The balance is located inside the aircraft model and is fixedly connected to the aircraft model through a balance sleeve. The center of the main support unit is connected to the balance sleeve through a back support rod. Both sides of the main support unit are respectively connected to the driving connectors on both sides of the open large angle of attack test system. The middle of the mirror support unit is connected to the balance sleeve through a mirror support rod and radial shock absorption / limiting structures at both ends thereof. Both sides of the mirror support unit are respectively connected to the driving connectors through angle adjustment seats. The flexible adjustment unit is respectively connected to the mirror support rod and the mirror support unit. The present invention can accurately deduct the aerodynamic interference amount of the bracket part of the open large angle of attack test system on the aircraft model, obtain accurate aerodynamic force loads, and provide necessary technical support for the wind tunnel test of the aircraft model.

Description

Technical Field

[0001] The present invention belongs to the field of wind tunnel tests, and particularly relates to a flexible measurement device for support interference in an open large angle of attack test system. Background Art

[0002] In wind tunnel tests, the influence of the model support on the flow field around the model and the measured values of aerodynamic forces is called support interference. Measuring and correcting support interference is an important part of wind tunnel test data correction. The main support and the mirror support are used to support the model in different combined states, and the aerodynamic loads of the model under different combined support states are processed with each other to obtain support interference. The commonly used measurement methods are divided into the two-step imaging method and the three-step imaging method. The open large angle of attack test system can realize large angle of attack and large sideslip wind tunnel tests of the model in the tail support state, and has the advantages of a large attitude angle range and a unified support method for positive and negative angle of attack ranges. However, due to its structural characteristics, there are problems in measuring the tail support interference. First, in order to minimize the entry of the main body frame of the test system into the wind tunnel flow field, the lateral span of the open large angle of attack test system is greater than the width of the wind tunnel test section, reaching more than 6 m. The commonly used method of suspending the tail strut into the model internally will cause the tail support mirror support to become a large-size cantilever structure, and there will be an end jitter problem under wind load, which is very likely to collide with the model and lead to incorrect measurement results. Second, in order to reduce the load on the driving device, the tail support mirror support needs to be designed with light weight, resulting in low structural stiffness and strength, and there are large changes in structural deformation and jitter under different attitude angles and wind loads, which is not conducive to the design of the system. Finally, if the main support is directly connected to the tail support mirror support, the jitter of the tail support mirror support will be directly transmitted to the balance and the model, which is not conducive to the measurement of the true load of the model. Summary of the Invention

[0003] Based on the above deficiencies, the present invention proposes a flexible measurement device for support interference in an open large angle of attack test system, which can effectively solve the problems of serious jitter of the mirror support due to large span and high wind speed and the collision of the front section of the mirror strut with the aircraft model during the wind tunnel test, and realize the measurement of the tail support interference in the open large angle of attack test system.

[0004] The technical solution of the present invention is: a flexible measurement device for support interference in an open large angle of attack test system, including a balance, a main support unit, a mirror support unit, and a flexible adjustment unit. The balance is located inside the aircraft model and is fixedly connected to the aircraft model through a balance sleeve. The center of the main support unit is connected to the balance sleeve through a back support rod. The two sides of the main support unit are respectively connected to the two-side drive connectors of the open large angle of attack test system. The middle of the mirror support unit is connected to the balance sleeve through a mirror support rod and the radial shock absorption / limiting structures at both ends thereof. The two sides of the mirror support unit are respectively connected to the two-side drive connectors of the open large angle of attack test system through mirror support angle adjustment seats. The flexible adjustment unit is respectively connected to the mirror support rod and the mirror support unit. This measurement device relies on the main support unit to bear the wind load during the wind tunnel test and simultaneously obtain the aerodynamic load. The mirror support unit has the same external dimensions as the main support unit and moves synchronously with the main support unit, and is used to simulate the interference amount of the tail support bracket during the wind tunnel test. The flexible adjustment unit effectively reduces the jitter of the mirror support unit due to the large span and high wind speed. When the support angle between the main support unit and the aircraft model changes, only the mirror support angle adjustment seats with different angles need to be replaced to complete the simulation measurement of the support interference in the corresponding support mode.

[0005] Further, the main support unit includes a locking nut, an L-shaped bracket docking seat, a back support rod, and two L-shaped brackets. The front end of the balance is connected to the inner wall of the aircraft model, and the rear end of the balance is connected to the front end of the balance sleeve. One end of the back support rod passes through the aircraft model and is fixedly connected to the balance sleeve. The other end of the back support rod is fixedly connected to the L-shaped bracket docking seat through the locking nut. The two sides of the L-shaped bracket docking seat are respectively fixedly connected to one end of the two L-shaped brackets. The other end of each L-shaped bracket is vertically connected to the two-side drive connectors of the open large angle of attack test system. The two-side drive connectors rotate at a given angle, and then drive the aircraft model to change the pitch angle to achieve the large angle of attack test.

[0006] Further, the mirror support unit includes a mirror L-shaped bracket docking seat, two mirror L-shaped brackets, a rear section of the mirror support rod, a mirror support angle adjustment seat, a front section of the mirror support rod, a sleeve flange, a universal ball radial shock absorption sleeve, and a radial shaft shock absorption sleeve. The two sides of the mirror L-shaped bracket docking seat are respectively connected to one end of the two mirror L-shaped brackets. The other end of each mirror L-shaped bracket is fixedly connected to the two-side drive connectors of the open large angle of attack test system through the mirror support angle adjustment seat. One end of the sleeve flange is connected to the rear end of the balance sleeve, and the inner hole of the other end of the sleeve flange is fixedly connected to the outer wall surface of the universal ball radial shock absorption sleeve. The front end of the front section of the mirror support rod is connected to the inside of the universal ball radial shock absorption sleeve. The rear end of the front section of the mirror support rod is connected to the inside of the radial shaft shock absorption sleeve. The outer wall of the radial shaft shock absorption sleeve is fixedly connected to the inner hole of the front end of the rear section of the mirror support rod. The rear end of the rear section of the mirror support rod is fixedly connected to the front end of the mirror L-shaped bracket docking seat through a flange.

[0007] Further, the universal ball radial shock-absorbing sleeve includes a universal ball seat sleeve. The outer wall of the universal ball seat sleeve is circular, and the inner wall is a regular hexagon structure. Six universal balls are evenly installed along the radial direction on each plane of the regular hexagon structure. The other end of the sleeve flange is radially fixedly connected to the universal ball seat sleeve through a plurality of countersunk head screws along the circumference. The six universal balls wrap the front outer wall of the front section of the mirror support rod, which is used to limit the radial jitter of the front end of the front section of the mirror support rod during the test, and at the same time allows the front section of the mirror support rod to slide along the axial direction.

[0008] Further, the radial shaft shock-absorbing sleeve includes a radial shaft seat. The outer wall of the radial shaft seat is circular, and the inner wall is a regular hexagon structure. The front end of the rear section of the mirror support rod is radially fixedly connected to the radial shaft seat through a plurality of countersunk head screws along the circumference. Six guide posts are evenly and fixedly installed along the radial direction on each plane of the regular hexagon structure. A hexagonal nut is threadedly connected to the bottom of each guide post. An arc-shaped support plate is slidably connected to each guide post. A spring is sleeved between each guide post and the arc-shaped support plate above it. The hexagonal nut is used to adjust the compression amount of the spring. The six groups of arc-shaped support plates elastically clamp the rear end of the front section of the mirror support rod, allowing the rear end of the front section of the mirror support rod to jump in the radial direction within a certain range, and allowing the front section of the mirror support rod to move along the axial direction.

[0009] Further, the flexible adjustment unit includes two tension ropes on both sides and two tension regulators. Threaded pins are respectively fixedly connected to the corresponding positions on both sides near the front end of the rear section of the mirror support rod. Threaded pins are also respectively fixedly connected to the corresponding positions on both side walls of the two mirror L-shaped brackets. Hoisting rings are fixedly connected to the corresponding positions on both sides of the docking seat of the mirror L-shaped bracket. One end of the tension rope on one side is fixedly connected to the threaded pin of the rear section of the mirror support rod on this side, and the other end of the tension rope on this side passes through the threaded pin on the mirror L-shaped bracket on this side and is fixedly connected to the hoisting ring on the docking seat of the mirror L-shaped bracket on this side through a tension regulator. The regulator applies a pre-tightening force to the mirror support unit.

[0010] The advantages and beneficial effects of the present invention are as follows: It can truly simulate the interference of the tail support bracket in the test, suppress the vibration of the tail support mirror bracket itself, effectively eliminate the influence of the mirror bracket jitter on the model load measurement by using a flexible structure, and avoid the collision between the mirror bracket and the model. It can effectively measure the bracket interference amount of the large angle of attack test system during the open wind tunnel test process. Through this device, the aerodynamic interference amount of the bracket part of the open large angle of attack test system on the aircraft model can be accurately deducted, effectively improving the accuracy of the wind tunnel test data, obtaining accurate aerodynamic loads, and providing necessary technical guarantees for the research and development of aircraft. Description of the Drawings

[0011] Figure 1 It is a three-dimensional view of the measuring device of the present invention;

[0012] Figure 2 This is the front view of the measuring device of the present invention;

[0013] Figure 3 This is the top view of the measuring device of the present invention;

[0014] Figure 4 is Figure 3 the A-A sectional view in;

[0015] Figure 5 is Figure 2 the B-B sectional view in;

[0016] Figure 6 is Figure 2 the C-C sectional view in; Specific embodiments

[0017] The following further illustrates the present invention by way of examples with reference to the accompanying drawings of the specification:

[0018] Example 1

[0019] As Figure 1 shown, a flexible measuring device for the interference of the support of an open large angle of attack test system includes a balance, a main support unit, a mirror support unit and a flexible adjustment unit. The balance is located inside the aircraft model and is fixedly connected to the aircraft model through a balance sleeve. The center of the main support unit is connected to the balance sleeve through a back support rod. The two sides of the main support unit are respectively connected to the two side drive connectors of the open large angle of attack test system. The middle of the mirror support unit is connected to the balance sleeve through a mirror support rod and the radial shock absorption / limiting structures at both ends thereof. The two sides of the mirror support unit are respectively connected to the two side drive connectors of the open large angle of attack test system through mirror support angle adjustment seats. The flexible adjustment unit is respectively connected to the mirror support rod and the mirror support unit. This measuring device relies on the main support unit to bear the wind load during the wind tunnel test and simultaneously obtain the aerodynamic load. The mirror support unit has the same external dimensions as the main support unit and moves synchronously with the main support unit, and is used to simulate the interference amount of the tail support during the wind tunnel test. The flexible adjustment unit effectively reduces the jitter of the mirror support unit due to the large span and high wind speed. When the support angle between the main support unit and the aircraft model changes, only the mirror support angle adjustment seats with different angles need to be replaced to complete the simulation measurement of the support interference in the corresponding support mode.

[0020] As Figure 2-3As shown in the figure, the main support unit includes a lock nut 1, an L-shaped bracket docking seat 2, a back support rod 3, and two L-shaped brackets 4. The front end of the balance 6 is connected to the inner wall of the aircraft model 8, and the rear end of the balance 6 is connected to the front end of the balance sleeve 7. One end of the back support rod 3 passes through the aircraft model 8 and is fixedly connected to the balance sleeve 7. The other end of the back support rod 3 is fixedly connected to the L-shaped bracket docking seat 2 through the lock nut 1. The two sides of the L-shaped bracket docking seat 2 are respectively fixedly connected to one end of the two L-shaped brackets 4. The other end of each L-shaped bracket 4 is vertically connected to the two-side drive connectors 5 of the large angle of attack test system. The two-side drive connectors 5 rotate at a given angle, and then drive the aircraft model 8 to change the pitch angle, so as to realize the large angle of attack test.

[0021] As Figure 2-4 shown in the figure, the mirror support unit includes a mirror L-shaped bracket docking seat 13, two mirror L-shaped brackets 17, a rear section of the mirror support rod 12, a mirror bracket angle adjustment seat 18, a front section of the mirror support rod 10, a sleeve flange 9, a universal ball radial shock absorber sleeve, and a radial shaft shock absorber sleeve. The two sides of the mirror L-shaped bracket docking seat 13 are respectively connected to one end of the two mirror L-shaped brackets 17. The other end of each mirror L-shaped bracket 17 is fixedly connected to the two-side drive connectors 5 of the large angle of attack test system through the mirror bracket angle adjustment seat 18. One end of the sleeve flange 9 is connected to the rear end of the balance sleeve 7, and the inner hole of the other end of the sleeve flange 9 is fixedly connected to the outer wall surface of the universal ball radial shock absorber sleeve. The front end of the front section of the mirror support rod 10 is connected to the inside of the universal ball radial shock absorber sleeve. The rear end of the front section of the mirror support rod 10 is connected to the inside of the radial shaft shock absorber sleeve. The outer wall of the radial shaft shock absorber sleeve is fixedly connected to the inner hole of the front end of the rear section of the mirror support rod 12. The rear end of the rear section of the mirror support rod 12 is fixedly connected to the front end of the mirror L-shaped bracket docking seat 13 through a flange.

[0022] As Figure 5 shown in the figure, the universal ball radial shock absorber sleeve includes a universal ball seat sleeve 19. The outer wall of the universal ball seat sleeve 19 is circular, and the inner wall is a regular hexagon structure. Six universal balls 20 are evenly installed along the radial direction on each plane of the six sides of the regular hexagon structure. The other end of the sleeve flange 9 is radially fixedly connected to the universal ball seat sleeve 19 through a plurality of countersunk head screws 21 along the circumference. The six universal balls 20 wrap the outer wall of the front end of the front section of the mirror support rod 10, which is used to limit the radial jitter of the front end of the front section of the mirror support rod 10 during the test, prevent it from colliding with the model, and at the same time allow the front section of the mirror support rod 10 to slide along the axial direction.

[0023] As Figure 6As shown, the radial shaft damping sleeve includes a radial shaft seat 22, the outer wall of the radial shaft seat 22 is circular, and the inner wall is a regular hexagonal structure. The front end of the rear section 12 of the mirror support rod is radially fixedly connected to the radial shaft seat 22 through a plurality of countersunk screws along the circumference. Six guide columns 23 are evenly fixedly installed on each side plane of the regular hexagonal structure along the radial direction. The bottom of each guide column 23 is threadedly connected with a hexagonal nut 24. An arc-shaped support plate 26 is slidably connected to each guide column 23. Each guide column 23 and the arc-shaped support plate 26 thereon are A spring 25 is sleeved therebetween, and the hexagonal nut 24 is used to adjust the compression amount of the spring 25, thereby adjusting the radial runout amount of the rear end of the mirror support rod front section 10. The six groups of arc-shaped support plates elastically clamp the rear end of the mirror support rod front section 10, allowing the rear end of the mirror support rod front section 10 to run in the radial direction within a certain range, and allowing the mirror support rod front section 10 to move in the axial direction, that is, the front end of the mirror support rod front section 10 is inserted into the rolling body composed of the universal ball 20, and the rear end of the mirror support rod front section 10 is inserted into the circular ring composed of the arc-shaped support plates 26.

[0024] like Figure 1-3 As shown, the flexible adjustment unit includes tension ropes 14 on both sides and two groups of tension adjusters 15. Threaded pins 11 are fixedly connected to the corresponding positions on both sides of the front end near the rear section 12 of the mirror support rod, and threaded pins 11 are also fixedly connected to the corresponding positions on the two side supporting walls of the mirror L-shaped brackets 17 on both sides. Hanging rings 16 are fixedly connected to the corresponding positions on both sides of the mirror L-shaped bracket docking seat 13. One end of the tension rope 14 on one side is fixedly connected to the threaded pin 11 of the rear section 12 of the mirror support rod on that side, and the other end of the tension rope 14 on that side passes through the threaded pin 11 on the mirror L-shaped bracket 17 on that side and is fixedly connected to the hanging ring 16 on the mirror L-shaped bracket docking seat 13 on that side through the tension adjuster 15. The adjuster 15 applies a preload force to the mirror support unit. The mirror support unit is an additional load for the system, so its weight is as light as possible. Since the span of the mirror support unit is 6.4m, the main body of the mirror support unit will shake severely at a wind speed of 70m. In order to improve the overall stiffness of the mirror support unit and reduce its vibration, a flexible adjustment unit is used to "softly" connect the two mirror L-shaped brackets 17, the mirror L-shaped bracket docking seat 13 and the mirror support rod rear section 12 into a whole through the tension rope 14. The tensioning degree of the system is adjusted by the tension regulator 15 installed on the tension rope 14, which effectively reduces the shaking of the mirror support unit.

[0025] In this embodiment, the driving motor (not shown in the figure) of the opening high angle of attack test system is driven to rotate at a given angle, thereby driving the aircraft model 8 to change the pitch angle to achieve a high angle of attack test.

Claims

1. A flexible measurement device for support interference in an open large angle of attack test system, comprising a balance, a main support unit, a mirror support unit and a flexible adjustment unit. The balance is located inside the aircraft model and is fixedly connected to the aircraft model through a balance sleeve. It is characterized in that: The center of the main support unit is connected to the balance sleeve through a back support rod. The two sides of the main support unit are respectively connected to the two-side drive connectors of the large angle of attack test system. The mirror support unit includes a mirror L-shaped bracket docking seat (13), two mirror L-shaped brackets (17), a rear section of the mirror support rod (12), a mirror bracket angle adjustment seat (18), a front section of the mirror support rod (10), a sleeve flange (9), a universal ball radial shock absorber sleeve, and a radial shaft shock absorber sleeve. The two sides of the mirror L-shaped bracket docking seat (13) are respectively connected to one end of the two mirror L-shaped brackets (17). The other end of each mirror L-shaped bracket (17) is fixedly connected to the two-side drive connectors (5) of the large angle of attack test system through the mirror bracket angle adjustment seat (18). One end of the sleeve flange (9) is connected to the rear end of the balance sleeve (7). The inner hole of the other end of the sleeve flange (9) is fixedly connected to the outer wall surface of the universal ball radial shock absorber sleeve. The front end of the front section of the mirror support rod (10) is connected to the inside of the universal ball radial shock absorber sleeve. The rear end of the front section of the mirror support rod (10) is connected to the inside of the radial shaft shock absorber sleeve. The outer wall of the radial shaft shock absorber sleeve is fixedly connected to the inner hole of the front end of the rear section of the mirror support rod (12). The rear end of the rear section of the mirror support rod (12) is fixedly connected to the front end of the mirror L-shaped bracket docking seat (13) through a flange. The flexible adjustment unit includes two-side tension ropes (14) and two groups of tension regulators (15). Threaded pins (11) are respectively fixedly connected to the corresponding positions on both sides of the front end of the rear section of the mirror support rod (12). Threaded pins (11) are also respectively fixedly connected to the corresponding positions on the two-side support walls of the two mirror L-shaped brackets (17). Hoisting rings (16) are fixedly connected to the corresponding positions on both sides of the mirror L-shaped bracket docking seat (13). One end of the tension rope (14) on one side is fixedly connected to the threaded pin (11) of the rear section of the mirror support rod (12) on this side. The other end of the tension rope (14) on this side passes through the threaded pin (11) on the mirror L-shaped bracket (17) on this side and is fixedly connected to the hoisting ring (16) on the mirror L-shaped bracket docking seat (13) on this side through the tension regulator (15). The regulator (15) applies a pre-tightening force to the mirror support unit. This measuring device relies on the main support unit to bear the wind load during the wind tunnel test and simultaneously obtain the aerodynamic load. The mirror support unit has the same external dimensions as the main support unit and moves synchronously with the main support unit, and is used to simulate the interference amount of the tail support bracket during the wind tunnel test. The flexible adjustment unit effectively reduces the jitter of the mirror support unit due to the large span and high wind speed. When the support angle between the main support unit and the aircraft model changes, only the mirror bracket angle adjustment seats with different angles need to be replaced to complete the simulation measurement of the bracket interference in the corresponding support mode.

2. A flexible measurement device for bracket interference in an open large angle of attack test system according to claim 1, characterized in that: The main support unit described above includes a lock nut (1), an L-shaped bracket docking seat (2), a back support rod (3), and two L-shaped brackets (4). The front end of the balance (6) is connected to the inner wall of the aircraft model (8), and the rear end of the balance (6) is connected to the front end of the balance sleeve (7). One end of the back support rod (3) passes through the aircraft model (8) and is fixedly connected to the balance sleeve (7). The other end of the back support rod (3) is fixedly connected to the L-shaped bracket docking seat (2) through the lock nut (1). Both sides of the L-shaped bracket docking seat (2) are respectively fixedly connected to one end of the two L-shaped brackets (4). The other end of each L-shaped bracket (4) is vertically connected to the two side driving connectors (5) of the large angle of attack test system. The two side driving connectors (5) rotate at a given angle, and then drive the aircraft model (8) to change the pitch angle, so as to realize the large angle of attack test.

3. The flexible measurement device for support interference in the large opening angle of attack test system according to claim 2, wherein: The universal ball radial shock absorber sleeve described above includes a universal ball seat sleeve (19). The outer wall of the universal ball seat sleeve (19) is circular, and the inner wall is a regular hexagon structure. Six universal balls (20) are evenly installed along the radial direction on each plane of the regular hexagon structure. The other end of the sleeve flange (9) is radially fixedly connected to the universal ball seat sleeve (19) through a plurality of countersunk screws (21) along the circumference. The six universal balls (20) wrap the outer wall of the front end of the front section of the mirror image rod (10) to limit the radial jitter of the front end of the front section of the mirror image rod (10) during the test, and at the same time allow the front section of the mirror image rod (10) to slide in the axial direction.

4. The flexible measurement device for bracket interference in an open-mouth large angle of attack test system according to claim 3, characterized in that: The radial shaft shock absorber sleeve described above includes a radial shaft seat (22). The outer wall of the radial shaft seat (22) is circular, and the inner wall is a regular hexagon structure. The front end of the rear section of the mirror image rod (12) is radially fixedly connected to the radial shaft seat (22) through a plurality of countersunk screws along the circumference. Six guide columns (23) are evenly and fixedly installed along the radial direction on each plane of the regular hexagon structure. A hexagonal nut (24) is threadedly connected to the bottom of each guide column (23). An arc-shaped support plate (26) is slidably connected to each guide column (23). A spring (25) is sleeved between each guide column (23) and the arc-shaped support plate (26) thereon. The hexagonal nut (24) is used to adjust the compression amount of the spring (25). The six groups of arc-shaped support plates elastically clamp the rear end of the front section of the mirror image rod (10), allowing the rear end of the front section of the mirror image rod (10) to jump in the radial direction within a certain range, and allowing the front section of the mirror image rod (10) to move in the axial direction.

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