Thermal diffusion effects in hydrogen-air and methane-air flames

The influence of thermal diffusion on the structure of hydrogen-air and methane-air flames is investigated numerically using complex chemistry and detailed transport models. All the transport coefficients in the mixture, including thermal diffusion coefficients, are evaluated using new algorithms which provide, at moderate computational costs, accurate approximations derived rigorously from the kinetic theory of gases. Our numerical results show that thermal diffusion is important for an accurate prediction of flame structure.