Lip and spread angle variable efficient duct

Abstract

The invention relates to a lip and spread angle variable efficient duct which is made of flexile duct wall materials. The upper end and the lower end of the outer side of the duct are fixed with at least one actuating cylinder, and the other end of the actuating cylinder is connected to a positioning rack. A numerical value sensor is arranged on the side wall above a spread opening of the duct and used for sensing whether air flow is separated or not due to the increased spread angle of the opening and feeding a sensor signal back to an ECU (Electronic Control Unit). Part or all regions of the inner wall of the duct are provided with pit features which can be adjustable pit flexible pasters consisting of MEMSs (Micro Electro Mechanical Systems). The duct can be used for regulating the lip and the tail spread angle in real time, can improve the efficiency of duct propellers, and can change the duct pull force under the condition of no change of other control conditions, improve the control accuracy, and reduce the coupling function in the aircraft control.

Description

technical field [0001] The invention relates to a duct, in particular to a high-efficiency duct with a variable lip and divergence angle, which belongs to the technical field of propeller (duct fan) aerodynamics, and is especially suitable for ducts that generate thrust on aircraft. Background technique [0002] With the development of vertical take-off and landing aircraft, ducted propellers and ducted fans have flourished in recent years and are widely used in many unmanned aerial vehicles and special aircraft. [0003] At present, when the ducted propeller and ducted fan (hereinafter referred to as ducted propeller) used to generate thrust or lift are used to control the force output, it is generally used to change the speed of the propeller or the propeller pitch (blade angle of attack). Changing the magnitude of the force, this adjustment process is accompanied by the change of the rotating state of the high-speed rotating propeller, which needs to overcome the huge cha...

AI Technical Summary

Problems solved by technology

[0003] At present, when the ducted propeller and ducted fan (hereinafter referred to as ducted propeller) used to generate thrust or lift are used to control the force output, it is generally used to change the speed of the propeller or the propeller pitch (blade angle of attack). Changing the magnitude of the force, this adjustment process is accompanied by the change of the rotating state of the high-speed rotating propeller, which needs to overcome the huge change of moment of inertia or change of aerodynamic force, so the response of the adjustment process has a certain degree of delay. For aircraft with attitude control, it has some adverse effects

In addition, since the torque generated by the ducted propeller needs to be balanced and offset so that the aircraft does not spin, the traditional tension control system will cause changes in the spin torque during the process of changing the tension, so the control has a coupling effect, which will be due to Changes in the control of the pulling force cause changes in other quantities, increasing the difficulty of control

In foreign countries, there is also a method of compensating the pressure by opening air holes at the lip, reducing the negative pressure at the lip, thereby changing the additional pulling force of the lip, but this method can only weaken and adjust the original pulling force, and cannot achieve a wider range. Increase or decrease adjustment

At present, there is also a plan to change the pressure distribution of the flow field in the duct through a plasma generator in the world, but because the technology is complex, it is not easy to realize, and there are certain difficulties. It is currently in the laboratory research stage.

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