Numerical Simulation of Two-Phase Flows Through Injection Nozzles

Abstract

The characteristic properties of an injection jet and the spray behind the exit of an injection nozzle depend on cavitation phenomena within the nozzle. The presented research project aims at modelling the distributions of pressure, velocity and phase fractions at the nozzle exit based on numerical simulation of the two-phase flow within the nozzle. The mathematical and physical description assumes the liquid and the gas within the cavitation bubbles as compressible, viscous and heat conductive fluids and also includes dynamical processes in the mixture. The solution of the Navier-Stokes equations for the mixture is approximated by a finite element method in two space dimensions and explicit in time using an improved FCT-strategy to achieve nonlinear stability. Linear aspects of stability were analyzed as well, especially with respect to the used homogeneous model and provided upper bounds for the time step. The method is applied for the simulation of transient processes in one- and two-phase flow through injection nozzles with constant or variable cross-section. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)