A Computational Analysis of the Radiative and Convective Processes that Take Place in Preheated and Non-Preheated Ovens

Abstract

This article presents a computational method that implements an analytical approach toward determining the thermal processes that take place in an electrically heated oven. The integral equations of radiative heat transfer were specialized to the three-dimensional temperature field in the oven and numerically evaluated. The radiative fluxes at the surfaces of a thermal load situated in the oven were thus obtained and combined with natural convection fluxes extracted from a well-established correlation. The net result was a set of predictions for the temperature history of a thermal load of which size, material properties, radiative surface characteristics, and location in the oven were varied. In addition, two modes of oven operation were considered: a preheated and a non-preheated oven. An alternative model for the experimental data was built on an algebraic representation utilizing a one-term, time-based exponential. That model enabled the identification of the effect of the thermal inertia factor; load size, material, and location; and radiative and convective heat transfer coefficients. Complementary experiments were carried out for all of the cases investigated here and excellent agreement with the predictions was observed.