Abstract: The chemically nonequilibrium boundary layers over ablating Teflon surface are numerically analysed.The effects of the gas models,the reaction rate constants and the wall catalysis on boundary layer properties are investigated.The results indicate that:the gas models have strong effects on the magnitude sequence of the species concentrations but the maximum difference of electron densities between the two models is only of one order of magnitude; the different floarocarbon reaction rate constants have much ...