High bypass ratio turbofan engine and its exhaust device with variable bypass exhaust area

Abstract

The invention provides a high-bypass-ratio turbofan engine and a variable bypass duct air exhausting area type air exhausting device thereof. The variable bypass duct air exhausting area type air exhausting device of the high-bypass-ratio turbofan engine is applicable to a civilian high-bypass-ratio turbofan engine nacelle adopting a variable bypass duct grid type reaction thrust actuating device.The air exhausting device comprises a flow resisting door, an outer moving cover and a reaction thrust mechanism, wherein a certain amount of clearances are formed between the flow resisting door andthe outer moving cover, and the flow resisting door is kept in a non-working state through the reaction thrust actuating mechanism; a certain amount of lap is generated between the outer moving coverand the outer wall of a fixed nacelle of the turbofan engine nacelle, so that a reaction thrust grid is prevented from air leakage; the reaction thrust actuating mechanism pushes the outer moving cover in the early working period, and thus the air exhausting area of a bypass duct of the turbofan engine can be changed; when the reaction thrust actuating mechanism continuously moves the outer moving cover, no amount of lap is generated between the outer moving cover and the outer wall surface of the fixed nacelle, and the flow resisting door is switched to a working state to generate reaction thrust force through the reaction thrust actuating mechanism.

Description

technical field [0001] The invention relates to an exhaust device for an aero-engine. Background technique [0002] For turbofan engines with high bypass ratio, the change of flight conditions has an important impact on the common working line of the fan and bypass. As the Mach number increases, the total temperature of the engine inlet increases, and the flow rate of the core engine decreases. If the bypass nozzle is in a critical state or a supercritical state, the bypass flow rate remains unchanged, so the bypass ratio increases. If the bypass nozzle is in a subcritical state, as the Mach number increases, the inlet ram ratio increases, and the bypass flow rate increases, so the bypass ratio increases faster. Therefore, when the bypass nozzle area remains constant, It is impossible to meet the best performance matching on the ground and in the air at the same time. Contents of the invention [0003] The purpose of the present invention is to provide an exhaust device ...

AI Technical Summary

Problems solved by technology

If the bypass nozzle is in a subcritical state, as the Mach number increases, the inlet ram ratio increases, and the bypass flow rate increases, so the bypass ratio increases faster. Therefore, when the bypass nozzle area remains constant, Unable to meet the best performance match on the ground and in the air at the same time

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