同轴突扩燃烧室低频不稳定燃烧数值模拟

采用大涡模拟耦合预混燃烧方法,建立了液体冲压发动机不稳定燃烧计算模型。对模型发动机进行了不稳定燃烧数值研究,计算得到的发动机内压强振荡和火焰传播过程与文献中的实验数据吻合较好。结果分析表明,突扩构形发动机内大尺度的旋涡结构支配了燃烧室中的火焰传播过程,旋涡运动耦合非稳态的燃烧热释放是激发燃烧室低频压强振荡的重要原因。

Numerical study of low frequency combustion instability in dumpe combustor

Large-eddy simulation(LES) and premixed combustion model have been efficiently implemented to study the combustion instabilities in ramjet combustors.The main objective is to predict dominant frequencies and various flow features of the combustors.Combustion instabilities in the ramjet dump combustor were numerically simulated.Low-frequency,large-amplitude instabilities are observed,and instability frequencies and flame spread during various operating conditions are in good agreement with experimental observations.The results show large vortices structures dominate the flame propagation and vortices convection coupled unsteady heat release excite pressure oscillation in ramjet combustor.