Scalar Radiative Transfer in Discrete Media with Random Oriented Prolate Spheroids Particles

Monte Carlo scalar radiative transfer simulation of light scattering in plane parallel slab is not a simple problem, especially in the study of angular distribution of light intensity. Approximate phase function such as Henyey-Greenstein is often used to simulate the Mie phase function. But even for sphere particle this function is sometimes a poor approximation of real phase function. For a spheroids particle, the angular scattering characteristics cannot be approximated as HG phase function with sufficient accuracy. In this paper, we study the transmission characteristics of light in parallel plane layer with randomly oriented prolate spheroids aerosol particles. Instead of using H-G phase function, we use sampling method to simulate real phase function of spheroid directly. A database of phase function with various scattering angle and azimuth angles for given spheroids aerosol particle is developed. The transmission characteristics calculated by scattering phase function sampling method and equivalent volume sphere H-G phase function method are compared. The effect of prolate spheroids particle size and form factor on optical transmission properties is analyzed. It is found that although the construction database of phase function takes a certain amount of computing time, for spheroid particles the sample phase function method, compared with the H-G phase function simulation method, can greatly improve the accuracy of transmittance calculation. Received 29 April 2011, Accepted 5 July 2011, Scheduled 24 July 2011 * Corresponding author: Zhensen Wu ([email protected]).