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축대칭 초음속 흡입구의 아임계 불안정성 연구

A Study on Subcritical Instability of Axisymmetric Supersonic inlet

  • 발행 : 2004.10.01

초록

초음속 흡입구 buzz는 입구에서의 충격파 패턴의 진동과 내부압력요동을 동반하는 불안정한 아임계 작동으로 정의할 수 있다. 이러한 유동섭동은 연소실 실화나 엔진의 구조직 손상을 일으킬 수 있다. 축대칭, 외부 압축형 흡입구에서 초음속 흡입구의 buzz 현상을 조사하기 위한 실험적 연구가 수행되었다. 자유류 마하수 2.0에서 카울 입구 직경이 30mm인 흡입구 모델이 시험되었다. 아임계 불안정성은 압력섭동의 주파수 및 입구에서의 충격파 구조 분석을 통해 조사되었다. 실험결과 전압럭 회복비는 0.42에서 0.78까지, 포획 면적 비는 0.34에서 0.98까지 변화했다. 아임계 유동의 주파수는 포획 면적비 감소에 따라 증가했으며 주파수는 범위는 $224{\sim}240Hz$였다.

Supersonic inlet buzz can be defined as unstable subcritical operation associated with fluctuating internal pressures and a shock pattern oscillating about the inlet entrance. The flow pulsations could result in flameout in the combustor or even structural damage to the engine. An experimental study was conducted to investigate the phenomenon of supersonic inlet buzz on axisymmetric, external-compression inlet. An inlet model with a cowl lip diameter of 30mm was tested at a free stream Mach number of 2.0. Subcritical instability was investigated by considering the frequency of pressure pulsation and shock wave structure at the inlet entrance. The results obtained show that total pressure recovery ratios were varied from 0.42 to 0.78, and capture area ratio from 0.34 to 0.98. The frequency of the subcritical flow increased with decrease in capture area ratios. Frequency was measured at $224{\sim}240Hz$.

키워드

참고문헌

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