Large-eddy simulation of combustion instability in a back-step flow etc15 Tracking Number 34Presentation: Session: Reacting and compressible flows Room: Room F Session start: 13:30 Wed 26 Aug 2015 Tomoaki Kitano kitano.tomoaki.88x@st.kyoto-u.ac.jp Affifliation: Kyoto University Ryoichi Kurose kurose@mech.kyoto-u.ac.jp Affifliation: Kyoto University Satoru Komori eftel@fluid.me.kyoto-u.ac.jp Affifliation: Kyoto University Topics: - Reacting and compressible turbulence, - Large eddy simulation and related techniques, - Turbulent combustion Abstract: A large-eddy simulation of combustion instability in a back-step flow is performed, and the effect of equivalent ratio on the combustion instability is investigated. Methane is used as the fuel and a two-step global reaction model is used for the reaction. As the turbulent combustion model, a dynamic thickened flame model is used. The results show that flame is stably formed behind the step by the recirculation flow. Large pressure oscillation and periodical change of flame shape are observed in the case of equivalent ratio of 1.0, and the power spectra of the pressure oscillation has peaks whose frequencies and ntensities well agree with those of the previous experimental study. The intensity of the pressure oscillation becomes much smaller in the cases of equivalent ratio of 0.8 and 1.3, and the change of flame shape also becomes smaller. |