Numerical investigation of a cavitating nozzle for jetting and rock erosion based on different turbulence models

Abstract

Cavitating nozzle jets play a crucial role for fuel extraction in the hydrocarbon industry and geothermal energy sector. However, accurate numerical simulation of the flow field in a cavitating jet is difficult. In this study, several turbulence models are used to simulate cavitating flow in a venturi nozzle. The flow dynamics and turbulence properties are analyzed and compared with experimental data. The study focuses initially on evaluating the models ability to reproduce periodic cavity shedding and extends it to the interaction between cavitation and turbulence by conducting the analysis on a local scale using profile stations. The results show for the first time, that standard turbulence models are able to reproduce unsteady cavitating flow with stages of generating, developing, shedding and collapse of the cloud cavity. The models are able to show the movement of the re-entrant jet responsible for breaking the cavity at the throat into secondary cavity that rolls up and moves downstream. However, when model data is compared with experimental profiles on a local scale, all turbulence models fall short of simulating turbulence-related aspects like Reynolds stress and turbulent kinetic energy. Thus, this study reveals the bottleneck to model cavitating flows accurately and can provide a reference for simulating cavitating flows in a nozzle to the energy industry.