Application of the zonal method to predict the thermal behavior of CFFF MHD radiant furnace

This research work is a theoretical investigation of heat transfer in a radiant furnace. The furnace that was analyzed is the radiant furnace of the Department of Energy (DOE) Coal Fired Flow Facility (CFFF). The approach that was applied in this work was that of utilizing background studies along with experimental data to apply a radiation zonal analysis to the furnace to predict its heat transfer characteristics. A brief description of the radiant furnace and its function in the Low Mass Flow (LMF) test train of the CFFF is presented . Included in these discussions are details on factors that affect heat transfer and the temperature field. A description of the zonal procedure that was applied to analyze radiant heat transfer is given. These discussions include geometric considerations and the physics concepts that are used. Details on the radiative transport properties of flue gases are given along with state-of-the-art methods for their determination in a gas and particle absorbing media. A generalized mathematical formulation for gas-particle mixture emissivity is developed. Also included are computations for the various radiative exchange areas that are required in using the zonal technique. The formulation for the radiative heat balance of the entire furnace system of zones is presented. A description of the computer program that was developed for this application is given. The required inputs to this program are noted and its usage in this research is demonstrated. The heat flux distributions that were computed are compared to data obtained from experiments and to other analyses. It was found that the zonal method predicted the same trends for heat transfer in the furnace as were measured experimentally and as had been computed using other radiation models. Sources of error for this method are detailed. Shortcomings of this method and suggested ways of improving it are cited with the estimates of the relative complexity that would be added by the incorporation of such improvements. For more accurate results, a finer zonal system needs to be used. However, using a finer zoning also increases the amount of computational time that is required.