The Effect of Heat Generation on Convective Heat Transfer for Laminar Flows in a Multipassage Circular Pipe Subjected to an External Uniform Heat Flux

Abstract

A literature survey indicates that heat transfer studies for laminar flows in multipassage circular pipes based on exact temperature distributions and including the heat generation effects are not available. The existing traditional calculation of convective heat transfer for flows in multipassage conduits are based on lumped parameter analyses which are neither rigorous nor exact. The interest for heat transfer coefficients based on exact temperature distributions is of practical importance in the design of heat exchangers involving flows in separated sections with independent heat generation densities. In this technical note, previous results are extended to include the effect of heat generation in the outer and inner flow regions. It was shown that the Nusselt numbers on the outer and separating surfaces can be defined for all practical purposes in three different ways. Of these three definitions, there are two that are the most suitable for the heat exchanger applications.