Numerical Simulation of Condensing Real Gas Flows

A generally applicable numerical simulation method has been developed to simulate the flow of a condensing real gas. The flow is described by the Euler equations, whereas the condensation process is modeled by Hill's method. Special emphasis is placed on the development of an equation of state, which accurately describes the behavior of a real gas (i.e. a gas at high pressure). The condensation process in a fully expanding quasi - 1D nozzle flow is considered, by applying either the perfect-gas law or the real - gas equation of state. Comparison of results shows that, by applying the perfect - gas law, the temperature and pressure are over-predicted, and consequently the condensation onset is delayed with respect to the real-gas case. Furthermore, two 2D test cases have been carried out with the full 3D method. The first test case is the transonic flow of an air/water mixture through a channel with a circular arc bump on the bottom. The inflow Mach - number is chosen such that a shockwave is formed in the flow over the circular arc. The second test case is the supercritical flow of an air/water mixture through a nozzle with very small cross-sectional area divergence downstream of the throat. Both test cases show that the condensation process is very sensitive to accurate shockwave resolution.