Journal of the Korean Society of Propulsion Engineers (한국추진공학회지)

The Korean Society of Propulsion Engineers (한국추진공학회)
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A Study on the Transitional Shock Separation Patterns in an Over-Expanded Nozzle

과팽창 노즐에서 발생하는 충격파 박리 패턴의 천이에 관한 연구

  • 이종성 (안동대학교 대학원 기계공학과) ;
  • ;
  • 김희동 (안동대학교 기계공학과)
  • Received : 2010.03.22
  • Accepted : 2010.05.13
  • Published : 2010.06.30
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Abstract

Numerical investigation was carried out on axisymmetric over-expanded rocket nozzle to predict flow fields of transitional shock separation patterns. The unsteady, compressible N-S equations with k-$\omega$ SST for turbulence model closure were solved using a fully implicit finite volume scheme. Computed results were in good agreement with previous experimental works. It was found that strong side-loads were generated during the transition of RSS to FSS due to the development of a vortex ring in the inviscid jet core region. Hysteresis phenomenon exhibited by the shock-separation patterns was also found during the start-up and shut-down processes.

과팽창 로켓노즐에서 발생하는 충격파 박리패턴의 천이 유동장을 예측하기 위해 축대칭 수치해석적연구를 수행하였다. 비정상, 압축성 N-S 방정식에 k-$\omega$ SST 난류모델을 적용하여, 유한 체적법으로 계산하였다. 종래의 실험적 연구 결과와 비교하였으며, 계산된 결과와 정성적으로 잘 일치하였다. 본 연구의 결과로부터 RSS에서 FSS로 천이할 때 가장 큰 횡력이 발생하며, 이는 비점성 제트 코어 영역에서 발생하는 Vortex ring의 발달로 기인됨을 예측하였다. 또한 엔진 시동과정과 정지과정에서 발생하는 히스테리시스 현상을 잘 모사하였다.

Keywords

References

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