A coaxial co-rotating propeller with variable phase difference

Abstract

The invention discloses a coaxial and co-directional propeller with variable phase difference. Two propellers with coincident rotating shafts are arranged forward and backward along the thrust direction of the propeller, including a front propeller, a propeller rotating shaft, a sliding sleeve and a rear propeller. Similarly, there is a certain phase difference between the rear propeller and the front propeller to ensure that it is far away from the wake helix of the front propeller. During actual operation, if the change of the forward ratio causes the wake helix to approach the rear propeller, the rear propeller will adjust the phase difference between it and the front propeller through the forward and backward movement of the sleeve, so that it can still be outside the wake region of the front propeller. . The present invention thus reduces the adverse aerodynamic disturbance and aerodynamic noise of the coaxial propeller system.

Description

technical field [0001] The invention belongs to the technical field of aircraft propulsion device design, and in particular relates to a coaxial coaxial propeller with variable phase difference. Background technique [0002] When the maximum diameter of the propeller is limited, the most important means to increase the thrust of the propeller is to increase the area of ​​the rotor, that is, to increase the solidity of the rotor. Increasing the solidity of the rotor can be achieved by increasing the blade chord length and increasing the number of blades. For example, propeller fighter jets in the 1930s mainly used two-blade and three-blade propellers, such as I-16 (two-blade) and La-9 (three-blade). But in the late 1940s, four-blade propellers gradually became mainstream, such as Ki-84, P-51 and so on. [0003] Considering that the propeller efficiency will decrease after the solidity of the rotor is greater than a certain range, the industry has proposed a coaxial reverse ...

AI Technical Summary

Problems solved by technology

[0004] For the single-propeller scheme, although increasing the solidity of the rotor can increase the thrust of the single-propeller propulsion device, this method also increases the unfavorable aerodynamic interference between the blades of the propeller, so that the aerodynamic efficiency of the propeller increases with the increase of thrust. increasing and decreasing

For the coaxial reverse propeller scheme, this scheme can ensure that the two propellers are in a better rotor solidity, but because the rotation directions of the two propellers are opposite, the rear propeller will pass through the wake of the front propeller continuously. It will produce a complex and periodic dynamic adverse aerodynamic disturbance, which will reduce the overall aerodynamic efficiency of the coaxial reverse propeller propulsion device

The aerodynamic efficiency of the propeller determines the thrust-to-power ratio of the aircraft. The decrease in aerodynamic efficiency means that the engine power required by the propeller increases under the same thrust, and the fuel consumption rate increases, which will shorten the range of the propeller aircraft.

There is also a constant high level of aerodynamic noise due to the periodic nature of the adverse aerodynamic disturbances of the counter-rotating coaxial propellers

This noise will reduce the comfort of the people on board and make the aircraft less concealed

Images