Parallelizing the Discrete Ordinates Method (DOM) for Three-Dimensional Radiative Heat Transfer Calculations using a Priority Queuing Technique

Abstract

A parallelizing algorithm based on a priority queuing system is developed for solving the three-dimensional radiative transfer equation (RTE) using the discrete ordinates method (DOM) in an absorbing-emitting medium. The classical iterative method of initializing intensity values at processor boundaries and conducting iterations until convergence is very inefficient, and hence a better technique is desired. The method developed here is called the staged technique and relies on the careful organization and prioritization of the multiple inherently serial calculations present in the classical algorithm. A parallel performance analysis is presented for this technique, and measured values of performance metrics are compared to theoretical values. Although theoretical values exhibit possibilities of efficiencies up to 50%, the measured values are lower due to parallel logic overhead. Overall, better performance is obtained for larger problem sizes solved on a relatively small number of processors, but performance can be low outside this configuration.