Analytical and Experimental Study of Combustion and Heat Transfer in Submerged Flame Metal Fiber Burners/Heaters

Abstract

A theoretical model has been developed to predict the thermal performance of inert, direct-fired, woven-metal fiber-matrix porous radiant burner. The local chemical heat release was modeled by a detailed mechanism, and convection heat transfer between the gas and the solid phases in the burner was described by an empirical heat transfer coefficient. The solid matrix was modeled as a gray medium, and the discrete ordinates method was used to solve the radiative transfer equation to calculate the local radiation source/sink in the energy equation for the solid phase. The fully coupled nature of the calculations without external specification of flame location represents a key advance over past efforts towards modeling of porous radiant burners, because for a given mass flow rate the actual heat loss from the flame determines its position and is not a free parameter. The calculated results for the burner surface temperature, the gas exhaust temperature and the radiation efficiency for a single layer Fecralloy burner were compared with experimental data from this laboratory and reasonable agreement was obtained for a range of operating conditions.