The Structure of Supercritical Fluid Free-Jet Expansions

摘要

Experimental and numerical studies are reported on the structure of supersonic free-jet expansions of supercritical CO_2 impacting on a flat plate.Numerical calculations for the axisymmetric,two-dimensional(2-D)expansion use a time-dependent finite difference method known as the two-step Lax-Wendroff technique,incorporating the Redlich-Kwong equation of state to model CO_2.The numerical results are compared with experimental optical shadowgraph measurements of the jet and shock wave structure,impact pressure and temperature measurements along the plate,and a thermocouple probe of the expansion.Approximations based on ideal gases and quasi-1-D flow analysis,often used by researchers,are found to be useful for these supercritical fluid flows.