Numerical Predictions of Turbulent Combined Forced and Natural Convection Heat Transfer Using Two-Equation Turbulence Models for Velocity and Temperature Fields (Aiding Flow)

Vertical flow in a uniformly heated pipe

Abstract

In this study, two-equation models for velocity and temperature fields are applied to an aiding flow of combined forced and natural convection in a uniformly heated vertical pipe and then predicted results were compared with experimental results.
The numerical calculations are in generally satisfactory agreement with the experimental data. The reduction of heat transfer in the combined convection regime is also found numerically, and this region corresponded to the region of 1.0×10^-5<Gr_d/ (Re_d^2.7 Pr^0.5) <1.0×10^-3. This reduction in heat transfer is thought to be caused mainly by turbulence suppression.