Turbulent heat transfer in the thermal entrance region of concentric annuli with uniform wall heat flux

Abstract

The problem of turbulent heat transfer in concentric annuli is analysed for the case in which there is a uniform heat flux at either annular surface. The solution is given for the thermal entrance region and the fully developed situation and may be extended by the principle of superposition to cases in whcih there are arbitrary axial variations in the wall heat flux at both annular surfaces. The solutions are given for radius ratios 2·88, 5·625, 9·37 and 50 with Reynolds numbers from 20000 to 240000 and for Pr = 0·01, 0·7 and 1000. There is good agreement with experimental results for annuli for Pr = 0·7 whilst some results for a radius ratio equal to 50 compare favourably with results for a circular tube for other Prandtl numbers.