Radiative heat exchange modeling inside an oven

The 3D nongray radiative heat exchange in a near-infrared commercial oven is modeled. The spectrum is divided into into four gray bands to model the narrow wavelength range in which the halogen heat source radiates, the wavelength dependence of the food surface emittance, and the absorption coefficient of the heat source cover glass. The model is used to estimate the heating of a cuboidal food sample for 1 min at different cyclic settings of a halogen radiant heat source. The model predictions agree with the experimental data, and capture the cover-glass and the food-surface temperature and heat flux histories very well. The band-wise distribution of energy absorption by the food reveals the separate contributions from the source and the oven walls. Comparison of the heating rates between the measured non-gray food-surface and the different gray food-surface emittance values establishes the necessity of the nongray treatment. © 2009 American Institute of Chemical Engineers AIChE J, 2009