Numerical and Experimental Study of Abnormal Thermo-Mechanical Effects in Supercritical Fluid

Abstract

At least three regions can be distinguished on the phase diagram where one-phase fluid has abnormal thermo-mechanical properties: (1) the region above the thermodynamic critical point, strictly the supercritical fluid (SCF); (2) the region close to the coexistence curve; and (3) the region where (d2p/dv2)S<0. This chapter is devoted to the experimental and numerical study of abnormal effects in (1) and (3) regions. The calculations are carried out with the use of equations of Navier-Stokes, mass conservation, energy balance, and van der Waals or perfect gas equation of state. Two basic characteristic features of the SCF near the critical point, the accelerated temperature rise in the bulk heated from boundaries (so-called “piston effect”) and very slow relaxation of the generated inhomogeneities of thermodynamic parameters are studied. For region (3) the abnormal regimes of propagation of the shock and rarefaction waves after decay of a discontinuity are found.