Convective heat transfer in hydrodynamically-developed laminar flow in asymmetrically-heated annuli : a three-temperature problem

Abstract

Heat transfer in hydrodynamically-developed flow in asymmetrically-heated channels and annuli has been studied extensively. This study is an extension of earlier work where heat transfer in an asymmetrically-heated parallel-plate channel was examined in a resistor-network framework. It was shown that the formulation of the problem in terms of a delta thermalresistor network has several advantages. A delta network can also be used to represent heat transfer in asymmetrically-heated annuli. Nevertheless, the evaluation of the three paired convective resistances that characterize the network is not straightforward. In the present paper, a new technique based on solutions of the energy equation with perturbed boundary conditions is proposed. The proposed technique is first verified by comparison with the results previously obtained for the parallel-plate channel problem. A superposition solution to the energy equation is obtained for hydrodynamically-developed laminar flow in an asymmetrically-heated annulus. The developed technique is then applied to the annulus problem to obtain the corresponding resistances. Results are validated by examining limiting cases.