CFD Simulation and Grid Study of a Cavitating Orifice Flow

摘要

A cavitating flow through an orifice is investigated by the use of computational fluid dynamics (CFD) with an ANSYS CFX solver. Turbulence is described by the Menter shear stress transport (SST) model, mass transfer due to cavitation by the Rayleigh-Plesset based default cavitation model. A grid study following the best practice guidelines known from literature has shown as not sufficient enough for the simulation of a cavitating flow. When refining the grid monitor values e. g. the mass flow rate reached convergence at a certain amount of elements, whereas the cavitation zones itself changed in shape and location until a significantly high resolution is reached. The SST turbulence model calculates the boundary layer with a wall function approach at high YPLUS values and resolves it at small YPLUS values. The accuracy of the simulation was increased by avoiding the use of the wall function approach.