Author(s): Reza Esmaili; Seyed Ali Akbar Salehi Neyshabouri; Amir Reza Zarrati
Keywords: Cavitating Flow; Step-into-Flow; Open FOAM; Mass Transfer Model
Abstract: A liquid is said to" cavitate" when vapor bubbles form and grow as a consequence of pressure reduction. A two-phase flow composed of a liquid and its vapor is called a" cavitating flow" .In this paper simulation of cavitating flow past steps-intoflow with four different heights of 12 mm, 10 mm, 5 mm and 2 mm is reported using the realizable k-εturbulence model and volume of fluid (VOF) technique. A transport equation model for the local volume fraction of vapor was solved and a finite rate mass transfer model was used for simulation of the vaporization and condensation processes. These simulations were performed using a finite volume, two phase solver available in the framework of the Open FOAM (Open Field Operation and Manipulation) software package. The mass transfer model of Kunz was used and its validation was performed through comparisons between numerical simulations and experimental data. The computed results were in good agreement with experimental data. In addition effects of step height on the cloud cavitation thickness and pressure distribution over the step were analyzed. According to the numerical results, increasing the step height resulted in formation of thicker cavitation cloud over the step, and also more pressure reduction.