Date of Award
Master of Science
Ryoichi S Amano
John R Reisel, Istvan G Lauko
Air Injection, Cavitation, CFD, Experimental, Hydro Turbines
Cavitation is a phenomenon that occurs in various turbomachinery applications causing drawbacks on the. Some of these downsides are damaging the components of the system, generating noise and vibration, and loss of the turbine efficiency over time. Thus, it is imperative to address issue of cavitation to increase the life span of the equipment in addition to improve the system performance. This thesis introduces a method used to mitigate the cavitation phenomenon in a 3-inch Kaplan hydro turbine via injecting air at the leading edge of the rotor blades. The study is based on modeling the turbine using Computational Fluid Dynamics (CFD) software as well as carrying out experimental tests. The simulations were conducted at different air injection pressures over a spectrum of rotational speeds using Large Eddy Simulation (LES) for turbulence and volume of fluid for multiphase interactions: water, vapor water and air. The cavitation behavior was observed first without aeration, then followed by air injection simulations to investigate the effect of aeration. Each case was simulated for 12 cycles at rotational speeds of 1000, 2000, 3000, 4000, and 5000 rpm. The Vapor Volume Fraction (VVF) and the output mechanical power were monitored throughout the simulations. The data acquired from the simulations were compared to the experimental results for verifications. It was observed that the cavitation was mitigated in both the computer simulations and the experiment testing reaching up to 49.7% as an average reduction, while the output power was reduced by 6.6%.
Al-Haddad, Muhannad R., "Investigation of Performance and Cavitation Treatment in a Kaplan Hydro Turbine" (2019). Theses and Dissertations. 2150.