Numerical prediction of wall temperatures for near-critical para-hydrogen in turbulent upflow inside circular tubes

Exacting analysis of forced convection heat transfer to near-critical fluids is hindered by a general lack of understanding regarding the effects of variable fluid properties on the flow and heat transfer processes. Presented herein is a method of including density fluctuations in the equations of turbulent transport. Results of a numerical analysis indicate that the method may be used to predict heat transfer for the case of near-critical parahydrogen in turbulent flow inside vertical tubes. Wall temperatures, heat transfer coefficients and velocities obtained by coupling the equations of turbulent momentum and heat transfer with a perturbed equation of state show good agreement with experiment. Axial and radial profiles of major flow variables have been included in the presentation of results.

Experimentally observed "M" shaped velocity profiles in near-critical fluid flows are predicted for two cases and the heat transfer enhancement/degradation effects of this phenomenon are demonstrated.