ANALYSIS OF STEADY-STATE REACTION FRONTS IN A POROUS-MEDIUM

A pseudohomogeneous model is used to analyze the steady state of a sharp reaction front in a porous medium. The reaction rate is described by the flame sheet approximation, and an asymptotic matching analysis is used to determine the temperature, conversion and position of the reaction front. Both adiabatic and nonadiabatic operations are considered, and the effect of radiation is included in the adiabatic case. The results show that there exists a maximum molar flux before blowout occurs. The critical molar flux is decreased by higher activation energies, but it is increased by higher rate constants and flame temperatures. Radiation further stabilizes the flame against blowout. Expressions are provided for the flame temperature, reactant conversion and the conditions when blowout occur. It is also shown that under certain conditions the front has two steady-state positions.