阅读说明：本技术 一种空腔噪声控制的分流装置及噪声控制方法 (Shunting device for cavity noise control and noise control method ) 是由 高飞 胡陈映 顾金桃 王美燕 肖乾 于 2020-12-29 设计创作，主要内容包括：本发明提供一种空腔噪声控制的分流装置及噪声控制方法,用于降低空腔内部噪声。本发明在空腔前部,即前缘后方的适当位置设置分流装置,强迫在空腔前缘的分离气流产生进一步分离流动：一部分气流向上偏折,减小对空腔后壁的冲击作用；另一部分气流向下偏折进入空腔,削弱自后壁反馈的扰动波；同时对空腔内部流场形态产生扰动,避免自激振荡的情况出现。本发明所设计的空腔噪声控制的分流装置结构形式简单,易于加工；所使用的空腔噪声控制方法有效,可以显著降低空腔噪声。(The invention provides a shunting device for cavity noise control and a noise control method, which are used for reducing the noise in a cavity. The invention arranges a flow dividing device at a proper position in the front of the cavity, namely behind the front edge, and forces the separated airflow at the front edge of the cavity to generate further separated flow: a part of the airflow deflects upwards to reduce the impact on the rear wall of the cavity; the other part of the airflow deflects downwards to enter the cavity, so that disturbance waves fed back from the rear wall are weakened; meanwhile, disturbance is generated on the flow field form in the cavity, and the self-oscillation is avoided. The shunting device for controlling the cavity noise has a simple structural form and is easy to process; the used cavity noise control method is effective, and the cavity noise can be obviously reduced.)

1. The shunt device for cavity noise control is characterized by comprising a cavity (1) and a shunt device (2); the cavity (1) is of a cavity structure with an opening at one side; the flow dividing device (2) is arranged at the front part of the cavity opening side and behind the front edge;

the flow dividing device (2) is of a wedge-shaped structure or a plate-shaped structure; the maximum height h of the flow dividing device (2) is larger than the maximum thickness t.

2. A shunt device according to claim 1, characterized in that the centre line of the shunt device (2) coincides with the plane of the cavity opening.

3. A flow divider device according to claim 1, characterized in that the distance s of the rear end surface of the flow divider device (2) facing away from the incoming flow direction of the air flow from the front edge of the cavity is greater than the maximum thickness t of the flow divider device (2);

the maximum thickness t refers to the maximum distance between the front end face and the rear end face of the flow dividing device (2).

4. A shunt device according to claim 3, wherein the ratio of the distance s to the length L of the cavity is no more than 5%.

5. A shunt device according to claim 3, wherein the ratio of the maximum thickness t of the shunt device (2) to the length L of the cavity is not more than 1%.

6. A shunt device according to claim 3, characterized in that the ratio of the maximum height h of the shunt device (2) to the height D of the cavity is not more than 10%.

7. A shunt device according to claim 3, wherein the width of the shunt device (2) corresponds to the width of the cavity (1).

8. A cavity noise control method using the flow dividing device of any one of claims 1 to 7, the method comprising:

arranging the flow dividing device (2) in front of the cavity opening side and behind the front edge;

the flow dividing device (2) adopts a wedge-shaped structure or a plate-shaped structure; the maximum height h of the flow dividing device (2) is greater than the maximum thickness t;

and the noise inside the cavity is reduced by adjusting any one or more of the maximum thickness t, the maximum height h, the wedge angle and the distance s of the flow dividing device (2).

Technical Field

The invention belongs to the field of airplane noise control, and relates to a shunting device for cavity noise control.

Background

Cavity structures are common structures of aircraft, such as landing gear bays, slat/flap bays, equipment bays, and magazine bays. During the taking off and landing process and the flying process of the airplane, when the cabin door is opened, the cavity is exposed to airflow, the incoming flow shear layer in the front of the cavity interacts with the airflow in the cavity, and self-oscillation is possibly generated to generate strong noise. On one hand, strong noise can affect the environment around an airport, causing noise pollution; on the other hand, strong cavity noise can lead to structural damage inside the cavity, equipment malfunction or malfunction, and in severe cases, flight safety can be compromised.

The current common cavity noise control device is to install a spoiler device, such as a swash plate device, a flat plate device, a sawtooth device, a cylindrical device, a perforated plate device, etc., at the front edge of the cavity. These devices have a cavity noise suppression effect, but these devices are closely related to the incoming flow velocity.

Disclosure of Invention

The purpose of the invention is as follows: a shunt device for cavity noise control and a noise control method are provided, which are used for reducing the noise inside a cavity.

The invention arranges a flow dividing device at a proper position in the front of the cavity, namely behind the front edge, and forces the separated airflow at the front edge of the cavity to generate further separated flow: a part of the airflow deflects upwards to reduce the impact on the rear wall of the cavity; the other part of the airflow deflects downwards to enter the cavity, so that disturbance waves fed back from the rear wall are weakened; meanwhile, disturbance is generated on the flow field form in the cavity, and the self-oscillation is avoided. The shunting device for controlling the cavity noise has a simple structural form and is easy to process; the used cavity noise control method is effective, and the cavity noise can be obviously reduced.

The technical scheme of the invention is as follows: in one aspect, a shunt device for cavity noise control is provided, which comprises a cavity 1 and a shunt device 2; the cavity 1 is a cavity structure with an opening at one side; the flow divider 2 is arranged in front of the cavity opening side and behind the front edge;

the flow dividing device 2 is of a wedge-shaped structure or a plate-shaped structure; the maximum height h of the flow dividing means 2 is greater than the maximum thickness t.

Further, the centre line of the flow dividing device 2 coincides with the plane of the cavity opening.

Further, the distance s from the rear end surface of the flow dividing device 2 far away from the airflow incoming direction to the front edge of the cavity is greater than the maximum thickness t of the flow dividing device 2;

the maximum thickness t refers to the maximum distance between the front end face and the rear end face of the flow dividing device 2.

Further, the ratio of the distance s to the length L of the cavity is not more than 5%.

Further, the ratio of the maximum thickness t of the flow dividing device 2 to the length L of the cavity is not more than 1%.

Further, the ratio of the maximum height h of the flow dividing device 2 to the height D of the cavity is not more than 10%.

Further, the width of the flow dividing device 2 corresponds to the width of the cavity 1.

In another aspect, there is provided a cavity noise control method using the shunt device as described above, the method including:

the flow divider 2 is arranged in front of the cavity opening side and behind the front edge;

the flow dividing device 2 is of a wedge-shaped structure or a plate-shaped structure; the maximum height h of the flow dividing device 2 is larger than the maximum thickness t;

the noise inside the cavity is reduced by adjusting any one or more of the maximum thickness t, the maximum height h, the wedge angle and the distance s of the flow dividing device 2.

The technical effects are as follows: according to the generation mechanism of cavity noise, the invention changes the flow field form in the cavity by adjusting the flow of the separated air flow at the front edge of the cavity, and meanwhile generates disturbance to the flow in the cavity, thereby avoiding the occurrence of self-oscillation. Analysis shows that the surface noise of the wall plate in different areas of the cavity is reduced by 7.3dB on average.

Drawings

FIG. 1 is a schematic structural view of a cavity shunting device;

fig. 2 is a schematic structural diagram of the wedge-shaped shunt device.

Detailed Description

Fig. 1 is a schematic structural diagram of a cavity shunt device, and in combination with fig. 1, in this embodiment, a shunt device for cavity noise control is provided, which includes a cavity 1 and a shunt device 2; the cavity 1 is a cavity structure with an opening at one side; the flow dividing device 2 is arranged in front of the cavity opening side and behind the front edge. The flow dividing device 2 is of a wedge-shaped structure or a plate-shaped structure; the maximum height h of the flow dividing means 2 is greater than the maximum thickness t.

The present embodiment forces the separation flow at the front edge of the cavity to generate a further separation flow by arranging the flow dividing device 2 in front of the cavity opening side and behind the front edge: a part of the airflow deflects upwards to reduce the impact on the rear wall of the cavity; the other part of the airflow deflects downwards to enter the cavity, so that disturbance waves fed back from the rear wall are weakened; meanwhile, disturbance is generated on the flow field form in the cavity, and the self-oscillation is avoided.

In this embodiment, the center line of the flow divider 2 coincides with the plane of the cavity opening, so that the flow divider is easy to install, and the maximum flow division is realized.

In addition, the distance s from the rear end surface of the flow dividing device 2 far away from the airflow incoming direction to the front edge of the cavity is larger than the maximum thickness t of the flow dividing device 2; the maximum thickness t refers to the maximum distance between the front end face and the rear end face of the flow dividing device 2. When s is 0 or s is smaller than the thickness of the flow divider 2, the flow divider 2 of the present invention will be the same as the conventional flow divider at the leading edge of the cavity 1.

In this embodiment, it is obtained through Computational Fluid Dynamics (CFD), computational aeroacoustics (CAA) or wind tunnel test methods that when the flow dividing device 2 satisfies one or more of the following conditions, the noise reduction can be significantly achieved, and the specific conditions are:

the ratio of the distance s to the length L of the cavity is not more than 5%; the ratio of the maximum thickness t of the flow dividing device 2 to the length L of the cavity is not more than 1%; the ratio of the maximum height h of the flow dividing device 2 to the height D of the cavity is not more than 10 percent; the width of the flow dividing device 2 corresponds to the width of the cavity 1.

Fig. 2 is a schematic structural diagram of a wedge-shaped flow divider, and when the flow divider 2 is of a wedge-shaped structure, the values of the windward angles α and β of the flow divider 2 are as follows: alpha is more than or equal to 0 degree and less than or equal to 90 degrees, beta is more than or equal to 0 degree and less than or equal to 90 degrees.

In this embodiment, a method for controlling cavity noise is provided by using the shunt device, where the method includes: the flow divider 2 is arranged in front of the cavity opening side and behind the front edge; the flow dividing device 2 is of a wedge-shaped structure or a plate-shaped structure; the maximum height h of the flow dividing device 2 is larger than the maximum thickness t; by adjusting any one or more of the maximum thickness t, the maximum height h, the wedge angle and the distance s of the flow dividing device 2, the separation degree of the incoming flow of the front edge can be further adjusted to reduce the noise inside the cavity.

The shunting device for controlling the cavity noise has a simple structural form and is easy to process; the used cavity noise control method is effective, and the cavity noise can be obviously reduced.