Radiation of a spherical particle of semitransparent material

This paper deals with the possibility of using the theory of radiation tran sfer to calculate the heat radiation of homogeneous spherical particles of semitransparent material, including the determination of the radial profile of radiated power. A comparison with the exact solution obtained by the Mi e theory is used to demonstrate that the equation of radiation transfer yie lds acceptable results with the particle diffraction parameter x greater th an or equal to 20. Examples of calculation for large particles illustrate t he transition from prevailing heat radiation of the central zone of a parti cle to the mode in which the radiation flux is defined by the particle surf ace layer. A new differential approximation is suggested for the descriptio n of radiation transfer in the refracting particle. The use of this approxi mation method (which may be treated as a modification of diffusion approxim ation) leads to a considerable reduction of the computation time while main taining the acceptable accuracy of the results, which is very important in solving problems of radiative-conductive heat transfer.