Comparison of Computational Results Obtained From a VOF Cavitation Model With Experimental Investigations of Three Inducers: Part I — Experimental Investigations; Part II — Numerical Analysis Available to Purchase

The paper presents full 3D numerical simulations and experimental investigations of the cavitating flow through three axial inducers. These inducers are identified by the blades leading edge angle at the periphery β_1T = 8°, 10°, 13° and are thus noted as Inducer 8°, Inducer 10° and Inducer 13°. They have the same tip and hub diameters. The numerical and experimental investigations were carried out at the LEMFI-Paris laboratory. This enabled us to explain the cavitating operation for off-design conditions. In Part I of this paper we describe the design methodology adopted for the inducers and which is deduced from literature and in house experience. Then the main experimental results are presented for the studied inducers at a range of flow rates and cavitation numbers concerning: • The overall performances: pressure head coefficient and efficiency versus several flow rates. • Critical cavitation number (5% and 15% of drop) versus the flow rate. In Part II of this paper, a review of the cavitating regime modeling and the cavitation VOF model used for this paper’s calculations is firstly presented. The numerical approach is based on a combination of the VOF technique with a truncated version of the Rayleigh-Plesset model predicting the complicated growth and collapse processes of bubbles. The cavitation model also features a control volume finite element discretization and a solution methodology which implicitly couples the continuity and momentum equations together. The numerical results of Part II concern: • The overall performances. • The numerically investigated water vapor volume fraction distributions and other CFD results, which enable us to explain the cavitating behavior for these inducers. • The location and sizes of the blade cavity and backflow vortex. Finally, the comparisons between experimental and simulated results on the overall performances, cavities sizes and cavities location are discussed. A good agreement between experimental and predicted results was found for a range of flow rates. The head breakdown in the simulations started at a different cavitation coefficient than that in the experiment.