可压混合层涡并放热效应的涡动力分析

 基于双元单步不可逆燃烧动力学简化模型 ,采用紧致差分算法直接求解二维可压 Navier-Stokes方程 ,研究了时间发展非预混扩散火焰平面反应混合层流动。拟序结构由数值线性稳定性分析方法设定的粘性可压最不稳定小扰动初场促生。随放热强度增大 ,得到了基频涡卷撕裂现象。涡动力分析表明 ,放热主要通过膨胀和斜压这两种强非线性过程抑制大尺度剪切涡的演化

VORTEX DYNAMICS ANALYSIS OF HEAT RELEASE EFFECTS ON THE ROLL-UP PAIRING IN COMPRESSIBLE MIXING LAYERS

The temporally\|developing plane reactive mixing layer with non\|premixed diffused flames is simulated numerically. A dual\|reactant single\|step irreversible simplified combustion model is employed. A fifth\|order upwind and sixth\|order symmetric compact finite difference hybrid algorithm (UCD5/SCD6) is introduced to solve directly the two\|dimensional compressible Navier\|Stokes equations with chemical source terms. A three\|stage third\|order Runge\|Kutta method is selected for time\|marching. The coherent structures in mixing layers are generated by an initial disturbance field of the most unstable viscous waves obtained through using the numerical linear stability analysis method. Three examples according to different heat release parameters are considered, namely no\|, low\|, and high\| heat release cases. The primary vortex roll\|up tearing phenomenon is captured under the high heat release condition. The result of vortex dynamics analysis shows that reactive heat release delays and/or damps the large\|scale shear vortex forming through the dilatation and baroclinic nonlinear effects.