Based on the simplified theoretical solution deduced by the authors，the temperature profiles in the burner，the flammable limit and maximum half cycle were theoretically predicted by a piecewise linear function.These solution were applicable to inert porous medium combustors with reciprocating flow without heat loss to the surrounding.The predicted flammable limits showed the same trends as experiments for gas velocities less than 0.12 m·s-1，indicating that the lean flammable limit was getting lower with increasing gas velocity.However，when the gas velocity was greater than 0.17 m·s-1，it had little effect on the flammable limits.Computational results also showed that the flammable limits could be extended with porous media of smaller pore sizes.In addition，it was shown that the predicted maximum half cycle was proportional to the product of gas velocity and the specific heat ratio of solid to gas.The combustor length had significant influence on the maximum half cycle and a longer length permitted a larger half cycle. The predicted flammable limits and maximum half cycle provided a guidance for the combustor design and some insights into the further improvement of combustor performance.