Single and multiphase CFD simulations for designing cavitating venturi

Abstract

Hydrodynamic cavitation (HC) is becoming a popular process intensification tool for many industrial processes. It has its applications in emulsification, advanced oxidation processes, nano-material synthesis etc. Venturi is one of the most commonly used device to generate hydrodynamic cavitation at laboratory as well as industrial scale. Recently researchers have taken interest to find the effect of the geometric design parameters of the venturi on cavitating flows.In the present work, cavitating flow in a venturi is simulated using Computational Fluid Dynamics (CFD). Optimum mesh size and suitable turbulence model for this such a flow were selected using a preliminary study. Single phase as well as multiphase simulations were carried out and the results were validated using experimental data of pressure drop and flow rate.Further, discrete phase model (DPM) was used to predict the possible path taken by multiple cavities, and the pressure and turbulence data along these paths was extracted to solve the Keller–Miksis equation for cavity dynamics simulations. Parameters like bubble radius, collapse pressure and collapse temperature of the cavity during its dynamic behavior were estimated from this model. A comparison between the results for single phase and multiphase models is made to propose a numerically inexpensive and reasonably accurate method to model cavitating flows in a venturi.