Cam driven cascade oscillating gust generator

Abstract

The application discloses a cascade swing gust generator based on cam driving, which comprises a blade rotating shaft, blades, a motor device, a bearing seat, a bearing installed on the bearing seat, a cam shaft supported on the bearing and rotating, a cam installed on the cam shaft, a push rod, a cam driven bearing and a return spring. The push rod is periodically moved up and down by the rotation of the cam and the return effect of the return spring. The end of the blade rotating shaft extending out of a wall surface is vertically fixed with a swing rod. A waist groove is arranged on the swing rod, and the push rod is provided with a pin shaft inserted into the waist groove. The periodic up-and-down movement of the push rod drives the swing rod and the blades to periodically swing, so that the blades swing in a sinusoidal rule to generate gusts. The technical scheme is convenient to install and disassemble, and the mechanical structure is simple, so the structure can be small and the cost is low. The application is used for researching and verifying the conditions of generating gusts in a low-speed wind tunnel and testing the aerodynamic load of a model under the action of gusts.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aerodynamics, and particularly relates to a cascade oscillation gust generator based on a small-size low-speed wind tunnel. BACKGROUND

[0002] The research on unsteady aerodynamics is always an important field in aircraft design, and gust is a certain wind disturbance with large intensity. When an aircraft encounters gust, additional unsteady aerodynamic force and moment are generated on the aircraft body, which has an adverse effect on the flight performance of the aircraft. Since the latter half of the last century, a large amount of research work has been done to better understand the influence of gust on the external flow field of the aircraft wing, and the aerodynamic response of the aircraft exposed to the disturbed flow has been studied by using theoretical, experimental and numerical methods. In order to carry out related gust flow field simulation experiments, a certain mechanical device needs to be installed in the wind tunnel to realize the disturbance of the flow field. The gust generator based on cascade oscillation to generate gust is an indispensable part of related wind tunnel experiments. In 2006, Walter et al. designed a FOV (Flow Oscillation Vanes) device installed on the sidewall of the ASE wind tunnel to generate harmonic gust in the HiLDA wing model experiment. In 2008, Ricci et al. designed a blade gust generator to verify the right and left of the X-DIA aircraft wing control system in flutter suppression and gust load mitigation, and evaluated the maximum gust speed of the gust generator under the condition of known incoming flow speed. Liu et al. studied the aeroelastic response of an elastic high-aspect-ratio wing under harmonic gust load excitation by using nonlinear elastic response analysis combined with wind tunnel experiments.

[0003] The traditional cascade oscillation gust generator has the disadvantages of obvious high-frequency vibration, complex mechanical control, large required motor power, and the like. Due to the complex control structure, the size of the wind tunnel is required to be large. In order to generate gust in a small-size wind tunnel, a new type of gust generator with simple mechanical control, high reliability and small size is needed. SUMMARY

[0004] The purpose of the present application is to provide a cascade oscillation gust generator which can generate gust in a sinusoidal manner by a simple structure and small size.

[0005] The technical scheme adopted by the piezoelectric motor of the present application is as follows:

[0006] A cam driving based cascade swing gust generator, comprising an experiment section; a blade rotating shaft and blades installed on the blade rotating shaft are arranged inside the experiment section, both ends of the blade rotating shaft are rotatably installed on the wall surfaces on both sides of the experiment section, and at least one end of the blade rotating shaft extends out of the wall surface; characterized in that the generator further comprises a driving device, the driving device comprises a motor device, a bearing seat, a bearing installed on the bearing seat, a cam shaft borne on the bearing and rotating, a cam installed on the cam shaft, a push rod, a cam driven bearing at the bottom of the push rod, a guide sleeve above the cam driven bearing and accommodating the push rod, and a reset spring between the guide sleeve and the cam driven bearing; the cam driven bearing abuts against the cam, after the cam rotating drives the cam driven bearing and the push rod to move upward to the highest position, the reset spring drives the cam driven bearing and the push rod to move downward again, and the periodic up-and-down movement of the push rod is realized by the rotation of the cam and the reset action of the reset spring; a swing rod is vertically fixed on the end of the blade rotating shaft extending out of the wall surface; a waist groove is arranged on the swing rod, and the push rod is provided with a pin shaft inserted into the waist groove, and the periodic up-and-down movement of the push rod drives the swing rod and the blades to periodically swing.

[0007] Further, the blade rotating shaft is provided with two blades arranged above and below in the experiment section.

[0008] Further, the swing amplitude of the blades is ±8°.

[0009] Further, the motor device is a reduction motor.

[0010] Further, the inlet section is used to receive the wind flow field generated by a centrifugal fan, and the gust generator is suitable for generating a gust flow field in a wind tunnel with a flow velocity below 30 m / s.

[0011] Beneficial effects: the cascade swing gust generator can make the blades swing in a sinusoidal rule to generate a gust, the technical scheme is convenient to install and disassemble, the mechanical structure is simple, the structure can be made small, national standard parts such as the bearing seat, bolts, keys, bearings, motors and motor supports are used, and the cost is low. The invention is used for researching and verifying the conditions of generating a gust in a low-speed wind tunnel and testing the aerodynamic load of a model under the action of a gust. BRIEF DESCRIPTION OF DRAWINGS

[0012] Fig. 1 It is a structural schematic view of the cascade swing gust generator in a wind tunnel.

[0013] Fig. 2 It is a structural schematic view of the cam and the push rod.

[0014] Fig. 3 It is a structural schematic view of the blades and the swing rod. DETAILED DESCRIPTION

[0015] Embodiments of the present application are described below in detail with reference to the accompanying drawings. The embodiments described below are examples for explaining the present application and should not be construed as limiting the present application.

[0016] The present application is directed to a cam-driven double-blade cascade oscillation gust generator for AF1300 low-speed wind tunnel. The gust generator can be applied to small-size wind tunnels with incoming flow speed below 30m / s to generate gust flow field. The oscillation frequency of the blades can be changed by controlling the rotation speed of the cam, and the oscillation amplitude of the blades can be changed by modifying the cam profile. In the present embodiment, the rotation speed of the cam is preferably 600rpm, and the oscillation of the blades is ±8°.

[0017] Please refer to Figs. 1 to 3 The cam-driven cascade oscillation gust generator includes an experimental section 1. The experimental section 1 is located in the middle of the AF1300 low-speed wind tunnel, which also includes an inlet section 2 at one end of the experimental section 1 and an outlet section 3 at the other end of the experimental section 1. The inlet section 2 is used to receive the wind flow field generated by a centrifugal fan (not shown). The gust generator is suitable for wind tunnels with incoming flow speed below 30m / s to generate gust flow field.

[0018] The experimental section 1 is internally provided with a blade rotating shaft 4 and a blade 5 installed on the blade rotating shaft 4. The two ends of the blade rotating shaft 4 are rotatably mounted on the wall surfaces on both sides of the experimental section 1. A transmission bracket 20 is also provided outside the wall surface, and at least one end of the blade rotating shaft 4 extends out of the wall surface. The gust generator further includes a driving device 6, which includes a motor device 7 (a reduction motor), a bearing seat 8, a bearing (not shown) installed on the bearing seat 8, a cam shaft 9 carried on the bearing and rotating, a cam 10 installed on the cam shaft 9, a push rod 11, a cam follower bearing 12 at the bottom of the push rod 11, a guide sleeve 13 above the cam follower bearing 12 and accommodating the push rod 11, a return spring 14 between the guide sleeve 13 and the cam follower bearing 12, a box seat 15 and a box cover 16. The guide sleeve 13 is located at the top end of the box cover 16, and the push rod 11 extends out of the box cover 16 from the guide sleeve 13. The motor device 7, the bearing seat 8, the cam shaft 9, the cam 10 and the return spring 14 are all inside the box seat 15 and the box cover 16.

[0019] The cam follower bearing 12 abuts against the cam 10. After the cam 10 rotates to drive the cam follower bearing 2 and the push rod 11 to move upward to the highest position, the return spring 14 drives the cam follower bearing 12 and the push rod 11 to move downward again. The push rod 11 moves periodically up and down with the rotation of the cam 10 and the return effect of the return spring 14. The one end of the vane rotating shaft 4 extending out of the wall surface is vertically fixed with a swing rod 17. The swing rod 17 is provided with a waist groove 18, and the push rod is provided with a pin shaft 19 inserted into the waist groove. The periodic up and down movement of the push rod 11 drives the swing rod 17 and the vane 5 to periodically swing to generate the gust flow field. In the embodiment, the vane rotating shaft 4 is provided with two and is arranged up and down in the experimental section.

Claims

1. A cam-driven cascade oscillating gust generator, comprising an experimental section; a blade rotating shaft and a blade installed on the blade rotating shaft are arranged inside the experimental section, both ends of the blade rotating shaft are rotatably installed on the wall surfaces on both sides of the experimental section, and at least one end of the blade rotating shaft extends out of the wall surface; characterized in that, The driving device comprises a motor device, a bearing seat, a bearing mounted on the bearing seat, a camshaft borne on the bearing and rotating, a cam mounted on the camshaft, a push rod, a cam follower bearing at the bottom of the push rod, a guide sleeve above the cam follower bearing and accommodating the push rod, and a return spring between the guide sleeve and the cam follower bearing; the cam follower bearing abuts against the cam, and after the cam rotates to drive the cam follower bearing and the push rod to move upward to the highest position, the return spring drives the cam follower bearing and the push rod to move downward again, and the periodic up-and-down movement of the push rod is realized by the rotation of the cam and the return effect of the return spring; one end of the blade rotating shaft extending out of the wall surface is vertically fixed with a swing rod; the swing rod is provided with a waist groove, and the push rod is provided with a pin shaft inserted into the waist groove, and the periodic up-and-down movement of the push rod drives the swing rod and the blade to periodically swing.

2. The cascade wind gust generator of claim 1, wherein, The blade rotating shaft is provided with two blades arranged above and below the experimental section.

3. Cascade oscillating gust generator according to claim 1 or 2, characterized in that The swing amplitude of the blade is ±8°.

4. The cascade wind gust generator of claim 1, wherein, The motor device is a reduction motor.

5. The cascade wind gust generator of claim 3, wherein, The device further comprises an inlet section at one end of the experimental section, the inlet section is used to receive the wind flow field generated by the centrifugal fan, and the gust generator is suitable for generating a gust flow field in a wind tunnel with an incoming flow velocity of 30 m / s or less.

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