关键词: 混合层, 有限差分, 数值模拟, 纳维-斯托克斯方程

Abstract: 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.

Key words: mixing layer, finite differ ence, numer ical simulat ion, N-S equations