A Flow Control Method Using Flexible Wall Surface to Improve Inlet Starting Performance

Abstract

The invention discloses a flow control method capable of improving starting performance of an inlet by use of a flexible wall surface and relates to a ramjet engine inlet. Type selection of a flexiblematerial is determined according to fluidity pressure oscillation frequency and amplitude when the inlet is not started; the size of the flexible wall surface is determined according to the size of an air flow separation area at the compression section inlet when the inlet is not started; the initial mounting position of the flexible wall surface is determined according to the initial position ofthe air flow separation area. When the inlet is not started, fluidity pressure is periodically oscillated, the flexible wall surface is driven to produce tiny oscillation, so that the oscillation flow field energy is transferred and dissipated toward the flexible wall surface, flow field oscillation is inhibited, and the purpose of improving the starting characteristic of the supersonic speed inlet is achieved. The flow field oscillation is inhibited through oscillation of the flexible wall surface with the flow field, and the starting characteristic of the supersonic speed inlet can be improved; the structure is simple, the control effect is remarkable, and the engineering application potential is high.

Description

technical field [0001] The invention relates to an air inlet of a ramjet engine, in particular to a flow control method for improving the starting performance of an air inlet by using a flexible wall surface. Background technique [0002] As the first aerodynamic component of the ramjet engine, the hypersonic air intake directly affects the working characteristics of the entire propulsion system. The stable starting state of the inlet port is the prerequisite for the normal operation of the hypersonic propulsion system. When the inlet port is not in the starting state, it will cause the combustion chamber to stall and other phenomena, and it is difficult for the aircraft to maintain the hypersonic flight state. Therefore, starting performance is one of the key parameters of hypersonic inlet, which is of great significance to the design of ramjet. [0003] There are many factors that lead to the non-start of the inlet, such as the flight Mach number is lower than the self-st...

AI Technical Summary

Problems solved by technology

However, the current research on the hypersonic inlet shows that there will be obvious unsteady flow field oscillation in the inlet during the non-starting process, and there will be dynamic evolution characteristics of separation package oscillation-small surge-large surge (Wang Weixing, Guo Rongwei. Unsteady flow characteristics of a hyperinlet below the self-starting Mach number. Acta Aeronautical Sinica, 2012,27(12):2733-2741)

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