Radiative heat flux characteristics of coupled heat transfer in tubes and comparison of random sampling modes

By numerical simulation, the radiative heat flux characteristics of coupled radiation and convection heat transfer in tube is investigated, and the random sampling modes for the Monte Carlo calculation of radiative heat transfer are compared. A laminar developing flow of high temperature gray medium in tube is considered in the investigation. The results show that, within a cross section of the tube, the magnitude of the radial radiative heat flux is equivalent to that of the axial radiative heat flux, but their distribution shapes are quite different. For a radiative heat transfer calculation by the Monte Carlo method, the use of the random sampling mode of weight-equivalent energy beams can eliminate the calculating error caused by a random sampling of different energy beams. And thus, by this random sampling, the calculating efficiency and precision can be improved obviously.