Numerical Simulation on Equivalence Ratio Fluctuation at the Fuel Injection Hole with respect to Pressure Fluctuation in a Combustion Chamber

연소실내의 압력 변동에 따른 연료 분사구에서의 당량비 변동에 관한 수치해석

  • 김현준 (한국과학기술원 기계공학과 대학원) ;
  • 홍정구 (한국과학기술원 기계공학과 대학원) ;
  • 신현동 (한국과학기술원 기계공학과)
  • Published : 2006.10.20

Abstract

It has been observed in experiments that combustion instability of low frequency (${\sim}$ 10Hz) results form the modulation of equivalence ratio at fuel injection hole when a pressure fluctuation propagates upwards along the channel of the burner under an unchoked fuel flow condition. In this study, a commercial program was used to determine how the fuel flow rate changed with respect to the pressure, velocity of the fuel flow and the mass fraction in a choked and an unchoked condition. The calculation focus on the upstream of the dump plane to know how the forced pressure with the fuel injection conditions affects the modulation of the equivalence ratio. Therefore, it is found that pressure fluctuation leads to oscillation of mass flow rate and then results in equivalence ratio modulation under the unchoked fuel flow condition.

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