Radial heat transfer at the wall in packed beds

Abstract

A literature survey indicates that adequate mathematical models are available for the study of heat transfer in packed beds. However, experimental data have been obtained at low Reynolds numbers only, below 3500. Experimental results are reported for a 7 in. diameter bed packed with 0.489 in. and 0.658 in. diameter glass spheres, with preheated air as the fluid flowing in the bed. Results indicate that the bed-to-wall heat transfer coefficient hw, based on the wall temperature and a bulk gas temperature, may be best correlated by the relation Nu = 2.35 Re 0.63 to a standard deviation of 11.4 per cent for values between 2,000 and 15,000.