CN220854109U

CN220854109U - Two-degree-of-freedom model supporting device for low-speed wind tunnel test

Info

Publication number: CN220854109U
Application number: CN202322446706.8U
Authority: CN
Inventors: 刘强; 徐悦; 周晓勤; 薛佳恒; 王一超; 宋砚鑫; 刘博涵; 郑嘉伟; 董世升; 徐常皓
Original assignee: Jilin University
Current assignee: Jilin University
Priority date: 2023-09-10
Filing date: 2023-09-10
Publication date: 2024-04-26
Anticipated expiration: 2033-09-10

Abstract

The utility model discloses a two-degree-of-freedom model supporting device for testing a fixed wing profile in a low-speed wind tunnel. The device comprises a force measuring balance, a scale base, an alignment tray, scale bulges, an L-shaped supporting rod, a U-shaped telescopic rod, a butterfly bolt and the like. The bottom of the scale base is arranged on the force measuring balance, the top of the scale base is matched with the alignment tray through precise threads, and the windward direction of a measured piece can be changed by rotating the alignment tray; the scale convex circle is arranged in the alignment tray through the shaft bracket, and the attack angle of the measured piece can be changed by rotating the convex circle; the measured piece is pressed and fixed by the pressing piece and the bolt, and keeps horizontal with the upper part of the L-shaped supporting rod. The device can realize the assembly of the model and the force measuring balance, and under the condition of fixed wind tunnel incoming flow direction, the angle between the incoming flow direction and the cross section of the model is changed by adjusting the angle between the base of the supporting device and the alignment tray, and the angle of attack of the model is changed by adjusting the angle of attack adjusting disc, so that the device has the advantages of simple structure, stable clamping and accurate positioning.

Description

Two-degree-of-freedom model supporting device for low-speed wind tunnel test

Technical Field

The utility model belongs to the technical field of wind tunnel experiments, and particularly relates to a two-degree-of-freedom model supporting device for a low-speed wind tunnel test.

Background

Wind tunnel testing is an important research means for performing design experiments and performance tests of micro aircrafts. In wind tunnel test experiments, a piece to be tested is arranged on a force measuring balance through a certain device, and when air flows through the piece to be tested, the balance senses forces in all directions received by the piece to be tested and generates a test result. In the actual test process, the problems of fixed installation direction, complicated attack angle adjustment method, low degree of freedom of the supporting device, difficult clamping and the like exist when the to-be-tested piece is fixed. The existing supporting methods for fixing the to-be-detected piece and adjusting the attack angle, such as a wind tunnel model fixing frame, can secondarily adjust the fixed height of the to-be-detected piece, but cannot accurately control the attack angle and the windward side of the model; and the wind tunnel bracket for demonstration experiments has the advantages of simple structure and low processing difficulty, but has the defect of precise adjustment of multiple degrees of freedom; for example, a wind tunnel experimental section model support for teaching can accurately adjust the attack angle, but the fixing mode is not described in detail. The model supporting device for the laboratory low-speed wind tunnel is difficult to adjust, process, fix and clamp with multiple degrees of freedom, and the supporting device is required to be disassembled and altered repeatedly during use, so that the working efficiency is affected.

Disclosure of Invention

The utility model aims to provide a two-degree-of-freedom model supporting device for low-speed wind tunnel test, which can simply and stably connect a piece to be tested with a force measuring balance under the requirements of multiple directions and variable attack angles, so that the test efficiency and accuracy are improved. The problem that the model supporting device of the low-speed wind tunnel in a laboratory is difficult to adjust, process, fix and clamp with multiple degrees of freedom and is required to be disassembled and assembled repeatedly and changed during use, so that the working efficiency is affected is solved.

The technical scheme adopted for solving the technical problems is as follows:

The two-degree-of-freedom model supporting device for the low-speed wind tunnel test comprises a force measuring balance 1, a clamping device of a piece to be tested and further comprises: the device comprises a scale base 2, an alignment tray 3 and scale bulges 4, wherein the alignment tray 3 is arranged above the scale base 2, bolts are arranged at the bottom of the alignment tray 3, and nuts matched with the bolts are arranged at the upper part of the scale base 2; shafts 10 are arranged on two sides of the scale convex circle 4, and shaft holes corresponding to the shafts 10 are arranged on two sides of the alignment tray 3; the scale base 2 is fixed on the force balance 1, and the clamping device of the workpiece to be tested is fixed on the scale bulge 4.

A bearing is arranged in the shaft hole of the alignment tray 3 and is connected with the shaft 10; the two sides of the alignment tray 3 are provided with butterfly bolts 9 for positioning the scale bosses 4.

A spring 13 is arranged between the bolt of the alignment tray 3 and the nut of the scale base 2.

The bolt of the alignment tray 3 is a rectangular thread, the flank angle beta=30°, and the friction angle ψ=0.1 rad.

The clamping device for the piece to be tested comprises an L-shaped supporting rod 5, a U-shaped telescopic rod 6, an upper pressing piece 7, a lower pressing piece 8, a bolt 11 and a nut 12 of the clamping device; the telescopic rod 6 is horizontally fixed on the L-shaped supporting rod 5, two upper pressing sheets 7 are fixed at two ends of the telescopic rod 6, and the lower pressing sheet 8 is connected with the upper pressing sheets 7 through bolts 11 and nuts 12; the other part of the L-shaped supporting rod 5 is vertically fixed on the scale convex circle 4.

The scale convex circle 4 is carved with scale marks, the alignment tray 3 is provided with an alignment line ①, and the angle of attack adjustment range in the alignment tray 3 is-40 degrees to 40 degrees.

Scale lines are carved on the outer ring of the scale base 2, and alignment lines ② are arranged on the alignment tray 3.

The utility model provides a two-degree-of-freedom model supporting device for testing a fixed wing section in a low-speed wind tunnel. The device comprises a force measuring balance, a scale base, an alignment tray, scale bulges, an L-shaped supporting rod, a U-shaped telescopic rod, a butterfly bolt and the like. The bottom of the scale base is arranged on the force measuring balance, the top of the scale base is matched with the alignment tray through precise threads, and the windward direction of a measured piece can be changed by rotating the alignment tray; the scale convex circle is arranged in the alignment tray through the shaft bracket, and the attack angle of the measured piece can be changed by rotating the convex circle; the measured piece is pressed and fixed by the pressing piece and the bolt, and keeps horizontal with the upper part of the L-shaped supporting rod. The device can realize the assembly of the model and the force measuring balance, and under the condition of fixed wind tunnel incoming flow direction, the angle between the incoming flow direction and the cross section of the model is changed by adjusting the angle between the base of the supporting device and the alignment tray, and the angle of attack of the model is changed by adjusting the angle of attack adjusting disc, so that the device has the advantages of simple structure, stable clamping and accurate positioning.

The utility model has the advantages that:

1. The device can be used for accurately controlling the angle of the cross section of the part to be tested relative to the incoming flow direction and the attack angle of the model through rotating the alignment tray and the scale convex circles, and has high testing precision.

2. The two upper pressing plates positioned on the same horizontal plane ensure that the piece to be tested can ensure absolute level under the state of 0-degree attack angle, the pressing plates have a certain distance from the device main body, the influence of the device main body on air flow disturbance is avoided, the structure is stable, and the test result is accurate.

3. When changing the measured angle of the piece to be measured, the piece to be measured and the supporting device do not need to be disassembled, the manual adjustment is realized, the operation is simple and convenient, and the testing efficiency is improved.

Drawings

FIG. 1 is a schematic view of a two-degree-of-freedom model supporting device for low-speed wind tunnel test according to the present utility model.

Fig. 2 is a schematic view of an alignment tray according to the present utility model.

Fig. 3 is a schematic view of a scale convex structure in the utility model.

Fig. 4 is a schematic structural view of a clamping device for a workpiece according to the present utility model.

In the figure: 1. a force measuring balance; 2. a scale base; 3. aligning the tray; 4. the scales are convex; 5. an L-shaped support rod; 6. a U-shaped telescopic rod; 7. pressing into tablets; 8. tabletting; 9. a butterfly bolt; 10. a shaft; 11. a bolt; 12. a nut; 13. and (3) a spring.

Detailed Description

The following describes specific embodiments of the present utility model with reference to the drawings.

As shown in fig. 1, the two-degree-of-freedom model supporting device for the low-speed wind tunnel test comprises a force measuring balance 1, a scale base 2, an alignment tray 3, scale bosses 4, an L-shaped supporting rod 5, a U-shaped telescopic rod 6, an upper pressing sheet 7, a lower pressing sheet 8, a butterfly bolt 9, a shaft 10, a bolt 11 and a nut 12.

The scale base 2 is cylindrical, a threaded hole is machined at the bottom, the scale base is fixed on the force measuring balance 1 through a bolt, a 360-degree scale is marked on the outer ring at the upper part, a precise internal thread is formed in the scale base, the top is fixed with the alignment tray 3 through the internal thread and aligned with an angle of 0 degree, the upper half part of the alignment tray 3 is a cubic cylinder, the lower half part of the alignment tray is a cylinder with a spring, a precise external thread is formed below the cylinder and matched with the scale base 2, a cylinder edge alignment line ② and a bottom surface fixing spring 13 are arranged; a semicircular column groove is milled in the cube above the alignment tray 3, threaded holes are formed in the positions of the left side and the right side opposite to the center of the circle, and a butterfly bolt 9 is installed, so that the purpose of positioning the scale convex circle 4 is achieved; punching holes on the front side and the rear side relative to the circle center of the scale convex circle 4, installing a shaft 10, erecting the scale convex circle 4 by a certain height, and simultaneously achieving the purpose of adjusting the attack angle of the workpiece to be measured; the front side is milled with an 80 deg. sector slot to the front of the scale bead 4 and is aligned with line ① at the middle lowest point of the sector. The bottom of the alignment tray 3 is a rectangular thread, the flank angle beta=30°, the friction angle ψ=0.1 rad, the thread lead angle gamma=0.44 rad and the thread pitch diameter d=0.03 m according to the transmission efficiency principle, and the spring rate is 60N/mm. When the incoming flow speed is 5m/s, the driving torque T=0.5N.m applied to the screw thread pair by wind force, the force applied to the screw thread pair by the spring is considered, the length of one screw pitch of the spring compression is considered, and the spring stiffness can meet the requirement. An L-shaped supporting rod 5, a U-shaped telescopic rod 6 and a clamping device are fixed above the scale convex circle 4. The whole scale bulge is cake-shaped, a plane is milled at the left and right 40-degree position of the top end, a hole is formed at the center of the bulge, the hole is in interference fit with a shaft 10, when the scale bulge is installed, two ends of the shaft are fixed with bearings assembled by the scale bulge 4, and the side surface of the bulge is separated from the inner surface of the alignment tray by a certain distance; the convex front surface is marked with scales from the leakage part of the alignment tray groove, the lowest point in the middle is 0 degrees, and 40 degrees are respectively left and right.

As shown in fig. 2, after the alignment tray 3 is fixed with the scale base 2, the spring 13 at the bottom of the alignment tray 3 is compressed, when the angle between the cross section of the piece to be tested and the incoming flow direction needs to be adjusted, the screw thread is rotated, the screw thread can be opened by different angles according to different required angles, and meanwhile, the spring is tensioned along with the screw thread, so that the screw thread can not lose stability when the test is performed; the angle between the cross section of the to-be-measured piece and the incoming flow direction can be accurately adjusted by rotating the alignment line ②.

As shown in fig. 3, the scale convex circle 4 is marked with (-40 degrees, 40 degrees) scale, and the angle of attack of the workpiece to be measured can be accurately controlled by rotating the convex circle and visually displayed in the sector groove, and the butterfly bolt 9 is screwed down after the angle of attack is determined, so that the position of the angle of attack is fixed.

As shown in fig. 4, the two sides of the piece to be measured are placed between the upper pressing piece 7 and the lower pressing piece 8, and are screwed by bolts 11 and nuts 12, so that the purpose of fixing the piece to be measured is achieved.

When the wind tunnel testing device is used, the force measuring balance is fixed in the wind tunnel, the force of wind tunnel airflow acting on the to-be-tested piece can be acquired through electronic equipment, and if the attack angle and the model windward direction need to be changed, the next stage of testing can be carried out only by adjusting the scale convex circle 4 and the alignment tray 3.

Claims

1. The utility model provides a two degree of freedom model strutting arrangement for low-speed wind tunnel test, includes dynamometry balance (1), awaits measuring a clamping device, its characterized in that: further comprises: the device comprises a scale base (2), an alignment tray (3) and scale bosses (4), wherein the alignment tray (3) is arranged above the scale base (2), bolts are arranged at the bottom of the alignment tray (3), and nuts matched with the bolts are arranged at the upper part of the scale base (2); shafts (10) are arranged on two sides of the scale bulge (4), and shaft holes corresponding to the shafts (10) are arranged on two sides of the alignment tray (3); the scale base (2) is fixed on the force measuring balance (1), and the clamping device of the part to be measured is fixed on the scale bulge (4).

2. The two-degree-of-freedom model support device for low-speed wind tunnel testing of claim 1, wherein: a bearing is arranged in the shaft hole of the alignment tray (3), and the bearing is connected with the shaft (10); and butterfly bolts (9) are arranged on two sides of the alignment tray (3) and are used for positioning scale bosses (4).

3. The two-degree-of-freedom model support device for low-speed wind tunnel test of claim 1 or 2, wherein: a spring (13) is arranged between the bolt of the alignment tray (3) and the nut of the scale base (2).

4. A two degree of freedom model support device for low speed wind tunnel testing according to claim 3, wherein: the bolt of the alignment tray (3) is rectangular threads, the flank angle beta=30°, and the friction angle ψ=0.1 rad.

5. The two-degree-of-freedom model supporting device for low-speed wind tunnel test of claim 4, wherein: the clamping device for the piece to be tested comprises an L-shaped supporting rod (5), a U-shaped telescopic rod (6), an upper pressing piece (7), a lower pressing piece (8), a bolt (11) and a nut (12) of the clamping device; the telescopic rods (6) are horizontally fixed on the L-shaped supporting rods (5), two upper pressing sheets (7) are fixed at two ends of the telescopic rods (6), and the lower pressing sheets (8) are connected with the upper pressing sheets (7) through bolts (11) and nuts (12); the other part of the L-shaped supporting rod (5) is vertically fixed on the scale convex circle (4).

6. The two-degree-of-freedom model support device for low-speed wind tunnel test of claim 5, wherein: the scale convex circle (4) is carved with scale marks, the alignment tray (3) is provided with alignment lines ①, and the angle of attack adjustment range in the alignment tray (3) is-40 degrees to 40 degrees.

7. The two-degree-of-freedom model support device for low-speed wind tunnel test of claim 6, wherein: scale lines are carved on the outer ring of the scale base (2), and an alignment line ② is arranged on the alignment tray (3).