Supersonic flows of dense gases in cascade configurations

Abstract

We examine the steady, inviscid, supersonic flow of Bethe-Zel'dovich–Thompson (BZT) fluids in two-dimensional cascade configurations. Bethe-Zel'dovich–Thompson fluids are single-phase gases having specific heats so large that the fundamental derivative of gasdynamics, Γ, is negative over a finite range of pressures and temperatures. The equation of state is the well-known Martin–Hou equation, and the numerical scheme is the explicit predictor-corrector method of MacCormack. Numerical comparisons between BZT fluids and lighter fluids such as steam are presented. It was found that the natural dynamics of BZT fluids can result in significant reductions in the adverse pressure gradients associated with the collision of compression waves with neighbouring turbine blades. A numerical example of an entirely isentropic supersonic cascade flow is also presented.