Investigation of the effects of fluid properties representation and boundary condition selection in numerical simulations of micro scale flows with phase change

Abstract

[EN] Cavitation is a phenomenon affected considerably by the underlying pressure waves that occur on similar time and length scales as the bubble dynamics. Thus appropriate representation of wave dynamics within numerical frameworks is of paramount importance for the prediction of the phase change process in the nozzle as well as the subsequent spray formation. In this paper we focus on investigating the sensitivity of the wave dynamics within a compressible Large Eddy Simulation framework with regards to downstream geometry and boundary representation. Diesel was used as working fluid and was injected at various pressures through a micro-channel. Results in terms of vapour fraction, velocity and pressure are compared with the experimental data of Winklhofer [30, 31]. The downstream domain length and reflectivity properties are shown to exert a significant effect on in-nozzle processes.