Influence of fin spacing and rotational speed on the convective heat exchanges from a rotating finned tube

The convective heat transfer from fins to air at rest has been evaluated for rotating annular fins. The fin cooling is studied using infrared thermography. The heat transfer coefficient can be obtained from a fin's thermal balance, during its cooling process and its temperature-time evolution. The influence of the fin rotational speed and the fin spacing on the convective exchanges is studied. The tests were carried out for rotational Reynolds numbers (based on the shaft diameter and the shaft peripheral speed) ranging from 400 to 30 000, for different fin spacings. A. correlation of the experimental data has been found. The relative influences of the rotational forced convection and the gravitational natural convection on the heat transfer from the fin surface have also been analyzed. (C) 2000 Elsevier Science Inc. All rights reserved.