Adiabatic heating (cooling) of a supercritical fluid with variation in its physical properties

Resumo

The piston effect (adiabatic heating or cooling) is investigated numerically for a fluid with parameters in the neighborhood of the thermodynamic critical point. The fluid represents a plane layer on one of whose boundaries a jump in temperature takes place. The temperature of the medium is higher than the critical temperature and the mean density is equal to the critical density. The mathematical model includes the Navier–Stokes and energy equations for a heat-conducting compressible gas and the Van der Waals equation of state. The characteristics of the linear piston effect (properties of fluid are almost invariable) are compared the analytic data. The features of the nonlinear piston effect accompanied by significant variation in the physical properties of the medium are investigated.