Heat transfer to variable property fluids in turbulent pipe flow

Abstract

The paper is concerned with heat transfer to (or from) fluids in turbulent flow through smooth pipes with moderate property variations. The objectives were to extend constant property eddy diffusivity models to variable property pipe flow in a systematic way, and to compute the effects of the variations of c p, k,ϱ, and μ separately and in combination for ranges of Re and Pr. This has been achieved to an extent but with the growing realization that eddy diffusivity models, even for constant properties, lack a logical foundations so that their extension to variable properties must be equally arbitrary. Nevertheless theoretical results derived from the model proposed in the paper should yield design predictions at least as reliable as could be obtained by direct use of the multiplicity of unsatisfactory and contradictory experimental correlations.