Fast Implementation of Heat Radiation in a Self-Consistent FDTD Analysis Tool for Microwave and Hybrid Ovens

Abstract

This paper presents an efficient simulation tool for conventional, microwave and combined heating. Two heat transfer mechanisms are included: conductive and radiant heat transfer. The conductive heat transfer is modeled by a finite difference algorithm. A modeling technique for radiant heat transfer in non-uniform grids has been developed and is here presented for the first time. A finite difference scheme is not applicable for the radiant heat transfer, as radiation from a material surface is not bounded to the immediate vicinity as is conductive heat transfer. Therefore ray optical methods are used. Rays connecting mutually visible surfaces are obtained by a new fast method. Necessary but acceptable simplifications allow fast computations. The algorithms are conveniently integrated together with an electromagnetic FDTD program into one simulation tool. Representative simulations are presented for an oven heated conventionally, by microwaves, and by a combination of both.