Journal of the Korean Society of Propulsion Engineers (한국추진공학회지)

The Korean Society of Propulsion Engineers (한국추진공학회)
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A Numerical Study on Acoustic Damping Induced by Gap between Baffled Injectors in a Model Rocket Combustor

모형 로켓 연소실에서 배플형 분사기의 간극에 의한 음향 감쇠 효과에 관한 수치적 연구

  • 손채훈 (세종대학교 기계항공우주공학부) ;
  • 이중연 (조선대학교 대학원 항공우주공학과)
  • Published : 2007.06.30
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Abstract

Acoustic damping induced by gap width between baffled injectors is investigated numerically, which are installed to suppress pressure oscillations in a model rocket combustor. The previous work reported that the baffled injectors show larger acoustic damping with the gap width between injectors. It is simulated numerically and its mechanism is examined. Damping factors are calculated as a function of gap width and it is found that the optimum gap is 0.1 mm or so. For understanding of the improved damping induced by the gap, dissipation rate of turbulent kinetic energy and vorticity are calculated as a function of the gap. Both parameters have their maximum values at the specific gap and especially, the dissipation rate has the same profile as that of damping factor. It verifies that the improved damping made by the gap is attributed to the increased acoustic-energy dissipation.

로켓 엔진의 음향 불안정을 제어하기 위해 모형 연소실에 배플형 분사기가 장착된 경우의 음향 감쇠 특성을 수치해석적으로 조사하였다. 기존에 보고된 배플형 분사기의 효용성을 확인하였고 분사기간 간극이 존재할 때 음향 감쇠 효과가 증대되는 메커니즘을 규명하였다. 여러 가지 크기의 간극에 따라 음향학적 감쇠능력을 조사하였고, 본 연소실에서는 0.1 mm 정도의 간극에서 최적의 감쇠능력을 가짐을 알 수 있었다. 음향 감쇠 효과가 증대되는 메커니즘을 규명하기 위해, 분사기 사이의 간극에 따른 에너지 소산율과 와도를 계산하였고, 소산율 변화 추이와 감쇠인자 변화 추이가 유사함을 알았다. 이를 통해, 간극에 의한 에너지 소산의 종대로 음향 감쇠 효과가 증가함을 알았다.

Keywords

References

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