Discussion of a Wrinkled Laminar Flamelet Model in a Diffusion Flame in Grid Turbulence

Abstract

The temperature has been measured in a field in which laminar hydrogen (6.0m/s at the center of a burner exit) was injected into a coflowing air stream (6.0m/s) with certain kinds of grid turbulence. It is shown that the ratio of a laminar flame length to the turbulent one is proportional to the turbulent Reynolds number, Re_l, (integral scale is considered a characteristic length) in the measured extent (Re_l≤1000), and therefore, that the integral scale of a reactant flow is an important parameter for the flames in this paper. The width of a flame displacement is estimated from the temperature profiles when the flame is assumed to be a wrinkled laminar flamelet. The width is also measured directly by a flow visualization method. Both the widths obtained by the two different methods agree well with each other. This indicates that the turbulent flame in this paper can be treated as a wrinkled laminar flamelet.