CALCULATION OF RADIATIVE TRANSFER IN NONGRAY GAS USING A NARROW-BAND MODEL AND MONTE CARLO SIMULATION M. Cherkaoui , M. Asbik , and A. Khmou UDC 621.039.51 Radiation transfer is treated by the application of a narrow-band statistical model (NBSM) that takes emission and absorption gas spectral structures into account. A Monte Carlo method (MCM) using a net exchange technique was developed to integrate the radiative-transfer equation in nongray gas. The proposed procedure is based on a net-exchange formulation (NEF). This formulation provides an efficient way of systematically fulfilling the reciprocity principle, which avoids some of the major problems usually associated with the Monte Carlo method; the numerical efficiency becomes independent of the optical thickness, highly nonuniform grid sizes can be used with no increase in computation time, and configurations with small temperature differences can be treated with very good accuracy. It is shown that the radiative term is significant compared to the conductive term in just two specific regions in the emitting and absorbing gas in the immediate vicinity of the wall and in the external part of the boundary layer. The exchange Monte Carlo method (EMCM) is described in detail for a one-dimensional slab. JEPTER74920199914 JEPTER7492014