Journal of the Korean Society of Propulsion Engineers (한국추진공학회지)

The Korean Society of Propulsion Engineers (한국추진공학회)
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A Numerical Study on Effects of Displacement of a Variable Area Nozzle on Flow and Thrust in a Jet Engine

가변노즐의 변위가 제트 엔진의 유동 및 추력특성에 미치는 영향에 관한 수치해석

  • Park, Junho (School of Mechanical and Aerospace Engineering, Sejong University) ;
  • Sohn, Chae Hoon (School of Mechanical and Aerospace Engineering, Sejong University) ;
  • Park, Dong Chang (The 1st Research and Development Institute, Agency for Defense Development)
  • Received : 2013.07.17
  • Accepted : 2013.09.17
  • Published : 2013.10.01
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Abstract

Variable area nozzle, where both throat and exit area vary, is required for optimal expansion and optimal nozzle shape upon operation of after-burner. Steady-state and transient analyses are carried out for each condition with and without afterburner operation and as a function of the location of the nozzle flap. Effects of that nozzle displacement on flow and thrust characteristics are analyzed from numerical results. With variable area nozzle adopted, the combustion field is variable in time, leading to periodically variable thrust. For off-design conditions, flow separation shows up due to over expansion at the flap tips and shock wave does in the nozzle due to under expansion. The undesirable phenomena can be solved by control of variable area nozzle.

노즐 목 및 출구 면적이 동시에 조절되는 축소-확대 형상의 가변노즐을 수치해석적으로 연구하였다. 최적 팽창 및 후기 연소기 구동시의 최적 노즐 형상 구현을 위해 가변 노즐이 요구된다. 후기연소기 작동유무와 노즐 플랩 위치에 따른 각 조건에 대한 정상상태 계산 및 이동격자 기법을 적용한 과도해석을 수행하였다. 노즐 가변에 의해 내부 유동장의 변화가 유발되었고, 추력이 주기적으로 변화하였다. 탈설계점에서 과대팽창으로 인해 노즐 출구 끝단에서 유동 박리 현상이 발생하였으며, 과소팽창에 의해 충격파가 발생하였다. 이러한 현상은 가변 노즐의 제어를 통해 해결할 수 있다.

Keywords

References

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