Compressible simulation of high-speed hydrodynamics with phase change

Abstract

The present paper focuses on a numerical approach based on the Riemann problem to simulate liquid flows with phase changes. Thereby, the flow properties include velocities from O(1) m/s to O(100) m/s and pressures from p approx 0 bar to O(1000) bar. The thermal and caloric behavior of liquid and vapor will be described by suitable equations of state that keep the considered governing equations hyperbolic in time. This enables us to study single-phase as well as two-phase wave propagation phenomena, which can have strong effects on the performance of dynamic systems, e.g. on high-speed hydrodynamics in injection nozzles or in high pressure valves. Our physical model is based on the assumption that the two-phase regime can be described as a homogeneous mixture that remains in thermodynamic and mechanical equilibrium. This model provides a macroscopic description of the phase change and is independent of empirical parameters. Subsequent to the description of the mathematical model and the numerical method, computations are carried out to demonstrate the accuracy and applicability of the numerical scheme to liquid flows for a large variety of industrial problems. Finally, the simulation results of the time-dependent cavitating flow through a 3-D injection nozzle will be presented.