One-dimensional numerical simulations of heat transfer on the piston effect

Abstract

Strong singularities in thermodynamic and transport properties appear in near-critical fluids, which give birth to the piston effect. In the present study, the piston effect is investigated numerically in a one-dimensional cavity filled with near-critical CO2, being heated at one side while the other side keeps at initial temperature. The thermodynamics model, which ignores velocity field and assumes uniform pressure field, is numerically solved by explicit finite difference method. The results are presented and discussed from two aspects. In the first part, the results show typical evolutions of temperature and density fields. The variations of temperature, density and pressure are results of competitions and eventual equilibrium between the heating piston effect and the cooling piston effect. In the second part, the results indicate influences of the critical proximity on the equilibrium. Results show that with the increase of critical proximity, piston effect gets weaker, equilibrium time gets longer, and equilibrium temperature becomes smaller.