Starting control method of rocket-based combined cycle engine inlet

Abstract

The invention provides a starting control method of a rocket-based combined cycle engine inlet. Whether indoor pressure of a combustor is greater than a first pressure threshold value and smaller thanor equal to a second pressure threshold value or not is judged, if yes, the mass flow rate of an internally-installed rocket is reduced, and the secondary fuel injection quantity is reduced, so thatthe indoor pressure of the combustor is reduced. When the indoor pressure of the combustor is reduced to be smaller than the first pressure threshold value, the mass flow rate of the internally-installed rocket is improved, and the secondary fuel injection quantity is improved, so that the indoor pressure of the combustor is improved to the first pressure threshold value. By changing a working state of the internally-installed rocket, the jet flow radius of the internally-installed rocket is changed, so that the practical equivalent internal shrinkage ratio of the inlet is adjusted; and meanwhile, the combustor pressure is correspondingly reduced due to reduced fuel flow, and the inlet can be restrained to be not started through the purging action of the high-speed jet of the internally-installed rocket on low-energy boundary layers.

Description

technical field [0001] The invention relates to the field of air-breathing combined propulsion systems, in particular to a rocket-based combined cycle engine. Background technique [0002] The Rocket-Based Combined Cycle (RBCC) engine organically integrates a rocket engine with a high thrust-to-weight ratio and an air-breathing ramjet engine with a high specific impulse in the same flow channel, and is compatible with ejection, subcombustion, and scramjet And pure rocket mode, to achieve high-performance work in wide speed range and large airspace. When designing the RBCC power system, researchers hope that the Mach number corresponding to the inlet start point and the engine ejection / subcombustion mode transition point is as low as possible in order to obtain wide compatibility and improve the overall performance of the engine. When the inlet is just started, its anti-backpressure ability is weak, and the engine has to complete the modal transition as soon as possible, and...

AI Technical Summary

Problems solved by technology

However, considering the important influence of the built-in rocket in the RBCC engine on the state and performance of the entire engine, the current method of adjusting only by reducing the pressure of the combustion chamber has limited adjustment ability. The problem of non-starting, if the intake port does not start, the air capture volume will drop sharply, which will affect the normal operation of the engine, thereby seriously weakening the overall performance of the engine. The flight attitude adjustment and other methods have a small adjustable range, which cannot flexibly meet the demand for rapid suppression of the RBCC inlet in the event of an extreme warning of non-start. Serious mechanical seal and high-temperature dynamic seal problems lead to poor mechanical realization of the scheme, or even need to assist more pneumatic adjustment methods, resulting in a greatly increased structural quality

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