Effects of radiation on the coupled heat transfer in a high temperature tube filled with porous media

The effects of radiation from solid matrix on the temperature distribution and heat transfer were numerically investigated by simulating the coupled heat transfer in a tube filled with porous media. The energy equations of fluid and solid phases were built with the local thermal non-equilibrium model. Monte Carlo method was used to solve the radiative heat transfer of solid matrix. The temperature discrepancy and effects of wall emissivity and structure parameters of porous media were analyzed without radiation. The results show that radiation strongly affects the temperature of the entrance region and a substantial discrepancy occurs when the radiation is neglected. The maximum deviation is 16% at the wall temperature of 1 500 K. The effect of wall emissivity on the temperature is small, which is less than 3% at the wall temperature of 1 500 K. In addition, when the porosity is high and pore diameter increases, the ratio of wall radiative heat flux increases and the effects of radiation become obvious.