Numerical Analysis of Convective Heat Transfer in Supercritical Water Flow Channels

Abstract

In this paper, two-dimensional laminar convective heat transfer of water at a supercritical pressure of 25 MPa in a horizontal rectangular duct has been investigated. The objectives were to understand the thermal and hydrodynamic behavior of fluid flow under different conditions. A set of governing equations containing the continuity, momentum and energy are solved simultaneously using CFD techniques. The finite volume method is employed to obtain the discretized forms of the governing equations. In the numerical solution of these equations, the SIMPLE algorithm is used for pressure-velocity computations. In all the cases studied in this paper, sub-cooled water at a supercritical pressure enters a duct with constant surface temperature which is near to the fluid pseudocritical temperature. For this type of fluid flow with forced convective heat transfer, the pressure, velocity and temperature fields are calculated. Numerical results show that as the fluid temperature becomes closer to the pseudocritical temperature (384.8 degrees C), the rapid variation of the fluid properties causes an unusual velocity profile for this type of convective flow. In the present work, the crucial influences of two main parameters, the Reynolds number and wall temperature on flow and heat transfer distributions, are thoroughly explored.