Heat transfer in industrial furnaces. Annual report, April 1991-March 1992

The thermal system models for indirectly-fired batch and continuous furnaces have been completed by coupling a one-dimensional radiant tube model with the furnace space model. For a given furnace geometry, it is now possible to specify the firing rates in individual radiant tubes and to predict the resulting load temperature profiles and heat transfer to the load while also calculating the exhaust gas temperature from each tube. A two-dimensional model of the processes within the radiant tube is being developed to calculate the rate of fuel burn-up and the convective heat transfer from the combustion products in the tube to the walls. The thermal system models for directly-fired batch and continuous furnaces are being validated with data from both small, experimental furnaces and full scale industrial furnaces. Predictions from the batch furnace model have compared quite favorably with measured data from a small furnace tested at the Gaswarme Institut in Germany. The continuous furnace model is being modified to begin validation studies with operational data from two industrial furnaces: a steel strip furnace used on a galvanizing line at Inland Steel in East Chicago, Indiana, and a walking beam furnace used for reheating steel slabs at the China Steel Corporationmore » in Kaohsiung, Taiwan.« less