NUMERICAL SIMULATION OF ORIFICE CAVITATING FLOWS USING TWO-FLUID AND THREE-FLUID CAVITATION MODELS

A number of numerical simulations is carried out to study the turbulent cavitating flow through an orifice. We use two different two-fluid (consisting of two interpenetrating liquid and vapor phases) and three-fluid (consisting of three liquid, vapor, and non-condensable gas phases) cavitation models to extend our study. We use the finite-volume method to solve the multiphase flow governing equations, the SIMPLEC algorithm to link the pressure and velocity equations, and the standard k-epsilon model to treat the turbulence closure problem. We fix the outlet pressure and change the inlet pressure suitably in our simulations. The discharge coefficient values obtained by the two chosen models are compared with each other and those of other reliable experimental and numerical works. The current study shows that there can be considerable differences between the results of two models in describing the inception of cavitations and their resulting vapor volume fraction and velocity distributions in the orifice. Generally, our results show that the three-fluid model provides better accuracy and physics. The current achievement resembles the importance of non-condensable gas consideration in improving the accuracy of numerical results for the orifice cavitating flow study.