In this work, ignition phenomena of the solid fuel in a confined rectangular enclosure have been numerically studied with emphasis on the effect of gas radiation. The time-dependent compressible SIMPLER algorithm for gas-phase governing equation and the FVM(finite-volume method) for radiative transfer equation are employed. After validating present solutions by comparison with those of previous works including steady natural convection and pure radiative heat transfer, detailed investigation into the ignition delay time in a rectangular enclosure is conducted by changing various parameters such as hot wall temperature, absorption coefficient of radiating gas, adiabatic wall emissivity and hot wall orientation. Effect of the absorption coefficient appeared differently with hot wall temperature. At below 993K, as the absorption coefficient increased, ignition was delayed, while at above 1100K, as increased, ignition quickened. There is transition area between 993K and 1100K. Because of different ignition mechanism, at below 993K, fuel gases play blockage effect, while at above 1100K, fuel gases serve as thermal source. In addition, ignition delay time was obtained by changing adiabatic wall emissivity and hot wall orientation. Ignition delay became shorter as emissivity became larger. Ignition delay time was found to be shorter when the hot wall was located at the bottom, due to the buoyancy effect.
