Parametrization of the temperature dependence of laminar burning velocity for methane and ethane flames

The power exponent a in the temperature dependence of laminar burning velocity S-L/S-L(0) =(T-u/T-u(0))(alpha) is usually considered an empirical parameter extracted from measurements performed at different temperatures. In this paper an analytical derivation of alpha is proposed, calculating the power exponent from the overall activation energy as: alpha Tu(0)-> Tu =E alpha/2R.X + x.This relation is verified against experimental burning velocity data measured with the heat flux method and chemical kinetic models for flames with equivalence ratios, Phi, from 0.6 to 1.6 at up to 368 K unburned gas temperature and 1 atm. Both methane and ethane were used as fuel. Laminar burning velocity predictions at elevated temperatures are made using proposed relation and the resulting values are in good agreement with existing data for methane flames up to 500 K. This indicates that the proposed mathematical derivation of alpha is accurate. In addition to providing a reliable extrapolation of the burning velocity at varying temperatures, isolating the temperature dependence of the power exponent alpha enables more accurate quantification of other factors, e.g., Phi, the unburned gas temperature and pressure, that influence laminar burning velocity. Additionally, it provides a simple means to evaluate the overall activation energy, E-alpha.