The cavitating flow in a mixedflow pump under the design working condition was simulated numerically with the SST turbulence model and homogeneous mixture cavitation model based on the Rayleigh-Plesset equations by solving the timeaveraged Navier-Stokes equations. The NPSHH curve was extracted from the results, the cavitation inception and development were captured as well. The features of vapour volume fraction distribution in the impeller were comparatively analyzed under the slight, critical and severe cavitation conditions. The results show that this pump has met the requirement on its cavitation performance. A cavity appears firstly on the blade suction surface near the leading edge and the shroud， as NPSH is reduced, it extends towards the hub and trailing edge.The tip cavity originates from the blade leading edge and develops into a strip along a blade contour on the shroud. The hub cavity accumulates near the blade trailing edge on the hub, further the vapour volume fraction on the hub is evidently larger than on the shroud. A similar cavity distribution is indentified in all the impeller passages, and the serious blockage due to cavity in the flow passages results in a sharp reduction in pump head under the sever cavitation condition.
Yuan Danqing, Chen Xiangyang, Bai Bin, et al. Research progress of cavitation and erosion in hydraulic machinery[J]. Drainage and Irrigation Machinery, 2009, 27(4): 269-272. (in Chinese)
Adrian S, Romeo S R, Liviu E A, et al. A new approach in numerical assessment of the cavitation behaviour of centrifugal pumps[J]. International Journal of Fluid Machinery Machinery and Systems, 2011, 4(1): 104-113.
Li Jun, Liu Lijun, Li Guojun, et al. Numerical prediction of cavitation flows in a centrifugal pump impeller[J]. Journal of Engineering Thermophysis, 2007, 28(6): 948-950. (in Chinese)
Pierrat D, Gros L, Pintrand G, et al. Experimental and numerical investigations of leading edge cavitation in a helicocentrifugal pump［C］／／Proceedings of the 12th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery. Hawaii:［s.n.］,2008.
Yang Zhengjun, Wang Fujun, Liu Zhuqing, et al. Prediction of cavitation performance of axialflow pump based on CFD[J]. Journal of Drainage and Irrigation Machinery Engineering, 2011, 29(1): 11-15. (in Chinese)
Wang Yong,Liu Houlin, Yuan Shouqi, et al. CFD simulation on cavitation characteristics in centrifugal pump[J]. Journal of Drainage and Irrigation Machinery Engineering, 2011, 29(2): 99-103. (in Chinese)
Fujiyama K, Kim C H, Hitomi. Performance and cavitation evaluation of marine propeller using numerical simulations[C]／／Proceedings of the 2nd International Symposium on Marine Propulsors. Hamburg:[s.n.], 2011.
Wang Lei, Chang Jinshi. Cavitation simulation of Francis turbine Runner for hydraulic optimization design[J]. Transactions of the Chinese Society for Agriculture Machinery, 2009, 40(9): 98-102. (in Chinese)