Flame curvature and preferential diffusion in the burning intensity of bunsen flames

Flame temperature distributions over axisymmetric and two-dimensional Bunsen flames have been experimentally measured for methane, ethylene, and propane mixtures with air, and interpreted on the basis of preferential diffusion and aerodynamic stretching induced by flame curvature. Results substantite the validity of the non-unity Lewis number interpretation of stretched flame phenomena, verify the theoretical prediction that deviations of the flame temperature from the adiabatic flame temperature can occur only in the simultaneous presence of stretch and preferential diffusion, and demonstrate that such a deviation can be correlated by a nondimensional stretch factor for extensive experimental data obtained with various concentrations, flow velocities, and nozzle diameters. Identification of such a correlation strongly suggests the possibility of synthesizing the diverse experimental data on stretched flames in accordance with the generalized expression derived theoretically.