LES stochastic modelling of cavitation with its applications in OpenFOAM

Licentiate thesis, 2016

Cavitation is a vaporisation process that commonly happens in high pressure injector nozzles nowadays. It has been shown by previous studies that cavitation has a significant influence on the subsequent atomization process, the quality of which would in turn heavily affect the quality of combustion. With the coming of the ever increasingly restrictive emission standard, studies into cavitation phenomena has attracted rapidly increasing amount of interest from both the academic and the industrial circle. However, due to the inheritant difficulties, cavitation still render itself a process that is hard to be quantified with the experimental facilities nowadays. While many of the commercial softwares, e.g. Ansys, STAR-CCM+, have integrated cavitation modules into their packages, the variety of models is still in a rapidly expanding phase. The open source CFD package OpenFOAM (Open Field Operation and Manipultation) has gone through a long developing stage and has been proved to be a highly matured and convenient CFD tool for many engieering applications. Although a great number of fundamental applications have been developed, the development of solvers and libraries which caters the need of specific physical problems remain to be an ongoing task. In this work, focus has been put specifically on the development of cavitation modeling. Several readily available cavitation models have been used, based on which, a more complicated stochastic ordinary differential equation (ODE) solver has been developed to facilitate a Monte-Carlo type treatment to the non-linear terms involved in the cavitation model.