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Method for restraining rotor noise based on sweepback paddle tip openings

A noise suppression and blade tip technology, applied in the field of helicopter rotors, can solve problems such as complex control systems and difficult technical implementation, and achieve the effects of reducing rotor-vortex interference noise, significantly reducing noise, and reducing airfoil resistance.

Inactive Publication Date: 2017-05-31
XIAMEN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The method of optimizing the shape of the blade tip and installing the blade tip vortex cutting device has a certain effect on suppressing the blade-vortex interference, but none of them can simultaneously take into account the performance of aerodynamics, vibration reduction and noise reduction
The method of exerting control force requires a complex control system, which is difficult to realize technically

Method used

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  • Method for restraining rotor noise based on sweepback paddle tip openings
  • Method for restraining rotor noise based on sweepback paddle tip openings
  • Method for restraining rotor noise based on sweepback paddle tip openings

Examples

Experimental program
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Embodiment 1

[0042] The swept-back hole design is carried out based on the CT rotor, the rotor radius is R=1.143m, the aspect ratio is 6, and the inner radius (undercut) is taken as the chord length C L =0.1905m, the sweep angle is 40°, and the sweep start position is 0.85R. Three annular ventilation holes are designed near the tip of the blade from the leading edge to the spanwise end surface. The centerline of the holes is located in the upper and lower symmetrical planes of the wing, and the exit direction of the holes is the spanwise direction. In order to achieve a better vortex cutting effect and reduce the influence of openings on the aerodynamic performance of the rotor, the diameter of each hole is selected to be 0.067C L , the distance between two adjacent holes is 0.157C L , the pipeline path is designed using Scheme 2. Figure 8 The three-dimensional vortex cloud diagram of the rotor with or without holes is shown. From the figure, it can be seen that the vortex tube produced...

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Abstract

The invention relates to a method for restraining a rotor noise based on sweepback paddle tip openings and relates to a helicopter rotor. According to the method for restraining the rotor noise based on the sweepback paddle tip openings provided by the invention, the air flow at the front edge of a paddle is introduced to an end face of a paddle tip and the strength of the paddle tip eddy is weakened, so that the effect of reducing paddle-eddy interfering noise can be achieved. The opening quantity, opening size and interval are confirmed on the sweepback paddle tip; a connecting pipeline is designed; and the opening position is confirmed. The sweepback paddle tip has the advantages of delaying shock wave and reducing profile drag, so that the sweepback paddle tip is widely applied to the high-speed helicopter. A paddle tip opening scheme is provided, more air flow at the front edge of the airfoil can flow into the pipeline and the air flow is jet out along the direction vertical to the paddle tip, so that the strength of the paddle tip eddy is weakened and the paddle-eddy interfering noise is reduced. According to the method for restraining the rotor noise based on the sweepback paddle tip openings, the structure is simple, the realization is convenient, no additional complex control system is required, the noise-reducing effect is obvious and the method is a potential rotor noise restraining scheme.

Description

technical field [0001] The invention relates to a helicopter rotor, in particular to a method for suppressing rotor noise based on a swept tip opening. Background technique [0002] Compared with fixed-wing aircraft, helicopters have advantages such as vertical take-off and landing, high maneuverability and air hovering, and have been widely used in both military and civilian fields. However, during the rotation of the helicopter rotor, the blade-tip vortex generated by the preceding blade collides with the succeeding blade to produce the Blade-Vortex Interaction (BVI) effect, resulting in a sharp change in the surface pressure distribution of the succeeding blade, resulting in a strong Paddle-vortex interference noise. Propeller-vortex interference noise is one of the main noise sources of helicopters, which has a significant impact on the stealth performance of helicopters. Therefore, how to reduce the propeller-vortex interference noise is the focus and difficulty of hel...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B64C27/46B64C27/467
CPCB64C27/463B64C27/467
Inventor 陈荣钱王李璨王旭朱呈祥尤延铖
Owner XIAMEN UNIV
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