GRAVITATIONAL EFFECTS ON LAMINAR CONVECTION TO NEAR-CRITICAL WATER INA VERTICAL TUBE

Numerical calculation is performed to study the strongly coupled heat transfer and flow of mater at near critical conditions in laminar flow in a vertical tube. Near the critical region fluid flow and heat tran sfer depend on the temperature and pressure because of large property variations that include transition between liquid-like behavior and ga s-like behavior. The two-dimensional (r, z) model includes the effects of variable thermodynamic and transport properties such as density, s pecific heat, viscosity, and conductivity, Heat transfer coefficient a nd profiles of temperature and velocity are shown in the developing re gion of the tube, The very large influence of gravity on the two-dimen sional flow and temperature profiles in the tube is shown. The effect of proximity to the pseudocritical point is considered, The tube wall is heated with constant wall heat flux and uniform flow is assumed in the inlet of the tube. Inlet fluid temperature, pressure, and Reynolds number are used as the main parameters.