Parallel-air inlet type rear duct ejector in variable cycle engine adjustable mechanism

Abstract

The invention provides a parallel-air inlet type rear duct ejector in a variable cycle engine adjustable mechanism. The parallel-air inlet type rear duct ejector comprises an actuator cylinder, a link arm, a rotating shaft, a sleeve, a bearing, a bearing pedestal, an elastic collar, a connecting rod, an inner engine case, an outer engine case, a valve body, a sliding strip, a friction block and a friction block installation platform. According to the parallel-air inlet type rear duct ejector in the variable cycle engine adjustable mechanism, the actuator cylinder is used for carrying out driving, so that the outlet area of an engine outer duct is continuously adjustable, the structure is simple, the number of parts is small, the weight is low, and the parallel-air inlet type rear duct ejector is higher in stability and reliability compared with the design scheme of an existing variable cycle engine rear duct ejector.

Description

technical field [0001] The invention relates to a parallel intake type rear duct ejector in an adjustable mechanism of a variable cycle engine, which is used to change the working state of the engine to adapt to different flight conditions, and belongs to the technical field of high-performance gas turbine engines in aerospace technology . Background technique [0002] The foreign variable cycle engine design started in the 1970s, while the domestic variable cycle engine design began in this century. The adjustable mechanism of the variable cycle engine mainly includes three parts: the mode switching valve, the front ducted ejector, and the rear ducted ejector. The rear ducted ejector is located after the low-pressure turbine and before the afterburner. The conversion valve and the front duct ejector are adjusted together to realize the conversion of the engine between the two cycle modes of turbofan and turbojet, so that the engine can have the best performance in a wider ...

AI Technical Summary

Problems solved by technology

The disadvantage is that the mechanism is designed with a synchronous ring and a driving ring, and the driving force of the actuator needs to be transmitted to the ejector valve body through a five-stage transmission mechanism of connecting arm-rotating shaft-connecting rod-driving ring-connecting rod. Due to the accumulation of deformation of each part and the accumulation of gaps at the joints, the valve body of the rear duct ejector will have a certain time lag relative to the actuator during the adjustment process, thereby reducing the reliability of the rear duct ejector; Due to the large number of parts in the mechanism, if the method of increasing the rigidity of the mechanism is used to control the accumulation of deformation, the weight of the mechanism will be greatly increased, which will weaken the performance advantages of the variable cycle engine

Its disadvantage is that the movement of the valve body is directly driven by the rotating shaft, including translation and rotation, of which only the axial translation affects the switching effect of the valve body, and the allowable movement range is small

The disadvantage is that the double-layer valve body design doubles the weight of the valve body, which will weaken the performance advantages of the variable cycle engine

Its disadvantages are: the outlet direction of the mixed air flow is almost vertical to the mainstream direction, which will cause a large mixing loss; relying on the rotating shaft to directly drive the movement of the valve body, including translation and rotation, of which only the axial translation affects the switching effect of the valve body. And when the movement range of the valve body is large, the rotation range of the rotating shaft is relatively large, so that the driving force of the actuator cannot be fully utilized.

Its disadvantages are: the use of multi-stage linkage mechanism will lead to increased weight and reduced reliability of the mechanism; the actuator is located behind the steps of the casing, and its installation puts forward special requirements for the shape of the casing

[0009] To sum up, the common deficiencies and shortcomings of the above-mentioned prior art include: most of the actuating mechanism is located inside the flow channel, which hinders the flow of air; The time lag increases the weight of the mechanism and reduces the reliability; the movement of the valve body includes translation and rotation, of which only the axial translation affects the switching effect of the valve body, the allowed movement range is small, and the driving force cannot be fully utilized; thin-walled cylindrical type The rigidity of the valve body is poor, and the improvement measures make the weight increase significantly

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