Turbofan engine

Abstract

A turbofan engine comprises all structures of a turbofan engine such as a fan, an outer duct, an axial-flow air compressor, an evaporative combustion chamber, a turbine and a tail jet pipe. The turbojet engine is characterized in that a bypass pipe and an inner exhaust valve are further included, an outer exhaust valve is arranged or not arranged on the bypass pipe between an air inlet and an air outlet of the bypass pipe, after the engine is started and operates, the inner exhaust valve is opened, by opening and closing of the bypass pipe, the inner exhaust valve and the existing or nonexistent outer exhaust valve, the supercharge ratio of the axial-flow air compressor or the fan is increased and kept unchanged, the increased supercharge ratio is not higher than the limitation borne by the fan, the axial-flow air compressor and a turbine according to the mechanical strength, turbine inlet temperature is kept unchanged, namely the supercharge ratio and thrust-weight ratio are increased, oil consumption rate is lowered, the levels of the fan, the axial-flow air compressor and the turbine are not increased, and the turbine inlet temperature is not raised.

Description

technical field [0001] The invention relates to a turbofan engine, in particular to a turbofan engine capable of increasing the supercharging ratio and the thrust-to-weight ratio, and belongs to the technical field of turbofans, especially military turbofan engines. Background technique [0002] In a turbofan engine, increasing the supercharging ratio of the fan and axial flow compressor can increase the thrust. To increase the supercharging ratio, at present, it is mainly to increase the number of stages of the fan, axial flow compressor, and turbine or to increase the number of stages before the turbine. Gas temperature; but the former increases the weight and volume, which is unfavorable for increasing the thrust-to-weight ratio. For example, the GE90, PW4084 and Ruida 800 turbofan engines used in Boeing 777 have more stages of compressors and turbines, and the boost ratio and total boost It is relatively high, but the thrust-to-weight ratio is not high; the latter must u...

AI Technical Summary

Problems solved by technology

[0002] In a turbofan engine, increasing the supercharging ratio of the fan and axial flow compressor can increase the thrust. To increase the supercharging ratio, at present, it is mainly to increase the number of stages of the fan, axial flow compressor, and turbine or to increase the number of stages before the turbine. Gas temperature; but the former increases the weight and volume, which is unfavorable for increasing the thrust-to-weight ratio. For example, the GE90, PW4084 and Ruida 800 turbofan engines used in Boeing 777 have more stages of compressors and turbines, and the boost ratio and total boost It is relatively high, but the thrust-to-weight ratio is not high; the latter must use high-temperature-resistant, high-performance turbine blade materials, coating materials, and advanced cooling technologies, such as M88, EJ200, and F119 using advanced single-crystal materials, directional crystallization materials, etc. Material and cooling technology, compared with the previous generation of military turbofan engines, the gas temperature before the turbine can be increased by 150°C-200°C, but it is very difficult to continue to increase; and the boost ratio of the current turbofan engines is fixed, which cannot be changed and improve

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