Author(s): Reza Esmaili, Seyed Ali Akbar Salehi Neyshabouri, Amir Reza Zarrati
Linked Author(s): Reza Esmaili
Keywords: Numerical model, stepped bed, cavitation potential, OpenFOAM, mass transfer model
Abstract: The objective of the present study is to numerically simulate the cavitating flow behavior on stepped bed similar to a stepped spillway using a finite volume, two-phase solver available in the framework of the OpenFOAM (Open Field Operation and Manipulation) software package. These simulations were performed using the realizable k-? turbulence 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. The mass transfer model of Kunz was used, and its validation was performed through comparisons between numerical simulations and the available experimental data conducted in a cavitation tunnel. The cloud of cavitation predicted by the numerical model agreed with the experimental results. The results also revealed that larger step heights are more prone to cavitation than smaller steps. The numerical model similar to experimental results showed that cavitation potential increased by increasing the steps angle corresponding to horizontal direction. According to the numerical results, the step tips are the main location of cavitation formation. It was also shown that proceeding downstream of the cavitation tunnel, as the average pressure in flow section decreases, the cavitation potential and thickness of the formed cavitation cloud increases
Year: 2017