Viscous dissipation in non-Newtonian flows - Implications for Nusselt number

Abstract

This article considers the effects of viscous dissipation on convection heat transfer rates in thermally developing, power-law fluid flows in constant wall temperature tubes. The finite difference solution is based upon the use of asymptotic boundary-layer scales, and the results maintain high accuracy (errors ±°° as z —> finite nonzero value). At the same axial locations, the wall temperature gradient remains well-behaved. This demonstrates that Nu, as usually defined, is an extremely poor measure of the local heat transfer rate in this region.