A Numerical Study of a Premixed Flame on a Slit Burner

A numerical study of a premixed methane/air flame on a 4 mm slit burner is presented. A local grid refinement technique is used to deal with large gradients and curvature of all variables encountered in the flame, keeping the number of grid points within reasonable bounds. The method used here leads to a large reduction in the number of mesh points, compared to global or line-by-line refinement techniques. The procedure to obtain the initial guess for the detailed model simulation, needed for the Newton-like solution method, is discussed. The method uses the result of a one-step global model simulation of the same geometry and an appropriate one-dimensional detailed model simulation. The method works fine for the computations presented here. The results of the detailed model are compared to those of the one-step global reaction model computation. Furthermore, using a direct photograph of the luminescence, the flame-tip height and the general flame shape of the detailed simulation are verified with the corresponding experimental flame. Although only a qualitative comparison can be made, both the height and the flame shape compare well.