Numerical Study of Turbulent Convective Cooling of Vertical Heat-Generating Rods Using Supercritical Water

摘要

Convection heat transfer in upward flows of supercritical water in rectangular tight rod bundles is numerically investigated using the commercially-available CFD software ANSYS Fluent© 15.The heat-generating rod with an inner diameter of 10.2 mm and the pitch-to-diameter ratio (P/D) of 1.098 is studied for mass flux ranging between 550 and 1270 kg/m~2s and heat flux of 560 kW/m~2 at pressures of 25 MPa.V2F eddy viscosity turbulence model is used and, to isolate the effect of buoyancy, constant values are used for thermo-physical properties with Boussinesq approximation for the density variation with temperature in the momentum equations. The computed Nusselt number normalized by that of the same Reynolds number with no buoyancy against the buoyancy parameter proposed by Jackson and Hall's criterion.A significant decrease in Nusselt number was observed in the rangeof10~(-7)