Analysis on Radiative Energy Transmittance Through Packed Spheres by Monte Carlo Med

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Radiative energy transmittance is studied through three-dimensional packed spheres with random arrangement by using a direct Monte Carlo simulation method. The sphere diameter is far greater than the wave length of the radiative energy. The following results are obtained.1. The radiative transmittance through regularly-packed spheres is lower than the one through randomly-packed spheres, and this effect becomes eminent when the packing density of the spheres becomes higher.2. To study the effect of side walls of the packed spheres on the transmittance, an experiment is carried out and the result is compared with the one obtained by using the direct Monte Carlo simulation. The result shows that the local transmittance through the thin layer of the bed adjacent to the side walls is lower than the one through other part of the bed due to the lower packing density at the layer. And, the total transmittance characteristics are considered to be the sum of the characteristics of the central area of the bed whose transmittance is lower and the characteristics of the peripheral area whose transmittance is higher.3. To substitute the rigorous but time-consuming direct Monte Carlo simulation method, a simple model is developed to analyze the transmittance of radiative energy through packed spheres by correcting the extinction coefficient and the scattering phase function of the continuous model. The result of the newly developed model agrees well with the result of the direct Monte Carlo method.