Analysis of aluminum plates under heating in electrical and natural gas furnaces

This paper analyzes the thermal storage characteristics of aluminum plates in furnaces during their heating for lamination under two sources of heat: an electrical resistance bank and a combustion process carried out with nat ural gas. The set of equations to model the furnace under operation with el ectrical energy, for air as the fluid, is presented. This supports the theo retical analysis for the system under operation with natural gas combustion products. A numerical procedure, using the software ANSYS, is applied to d etermine the convection heat transfer coefficients for heating by the air f low. Temperatures measured in a plate inside a real furnace are used as par ameters to determine these coefficients. Then convection and radiation heat transfer coefficients are determined for the natural gas combustion produc ts. Results are compared, indicating a possible gain of 5.5 h in relation t o a 19.5 h period of conventional electrical heating per plate. (C) 2000 El sevier Science Ltd. All rights reserved.