Numerical and experimental study of cavitating flow through an axial inducer considering tip clearance

This paper presents three-dimensional numerical simulations and experimental investigations of cavitating flow through an axial inducer. Particularly, this work focuses on the influence of radial tip clearance on cavitation behavior. Numerical analysis was carried out on two different configurations: first, the inducer was modeled without taking tip clearance into consideration. Later, the inducer was modeled with nominal tip clearance and some modifications of this. It was found that radial tip clearance has a significant influence on the overall inducer performance in the non-cavitating regime because of the small size of the inducer. Moreover, the effects of radial tip clearance are strong in inducer cavitation behavior. Numerical results and experimental data with nominal tip clearance were compared in cavitating and non-cavitating regimes and these were discussed. The cavitation model used for calculation is based on a single-fluid multiphase flow method, assuming thermal equilibrium between phases. It is based on the classical conservation equations of the vapor phase and a mixture phase, with mass transfer due to cavitation appearing as a source and a sink term in the vapor mass fraction equation. Mass transfer rates are derived from the Rayleigh-Plesset model for bubble dynamics.