Abstract
A semi-infinite solid fuel is quickly immersed in a hot gas flow and experiences a one-step heterogeneous reaction according to Arrhenius' formula without surface depletion. The mode of ignition was formulated to be applicable with a quasi-steady treatment of the gas-phase. First, the ignition times are computed by numerical method; secondly, they are obtained by asymptotic analysis for the limit of large activation energy. Comparison of the two shows the validity of a parametric ignition time formula obtained analytically. This theoretical formula is readily applicable and can be used for any configuration in which the heat-transfer coefficient is constant.