Laminar forced convection at zero gravity to water near the critical region

Abstract

Numerical modeling is carried out to analyze the heat transfer and fluid flow for water in the critical region in laminar tube flow under zero-gravity conditions. The model considers variable density, specific heat, viscosity, and conductivity. The effect of proximity to the critical point is also considered. To accurately predict property distributions, the numerical grid is clustered in the region where property variation is severe. The results of the modeling provide heat transfer and flow characteristics including profiles of temperature and velocity, the heat transfer coefficient, and the friction factor in the developing region of the tube. Constant wall temperature and constant wall heat flux are considered, and pressure, inlet fluid temperature, and Reynolds number are used as parameters. The calculation results show differences compared from results based on constant properties, and provide insight into the effects of the large property variations on heat transfer.