CFD analysis of cavitation flow for axial2flow pump based on FBM model

The w orking co ndit ion of the ax ial f low pump is changeable, and cavitat ion is easy t o occur, w hich can seriously affect the hy dr aulic performance of a pump. T o study the flow characteristics o f the ax ial flow pump under cavitat ion co ndition, nu2 merical simulatio ns and pr essure pulsatio n analysis o f cavitat ion flow in full channel w ere carried o ut. The superiority of FBM model in predicting the ex ter nal characteristics and cavitation performance of axial flow pump w as v erified by comparing the ex2 perimental data based o n calculated r esults o f different turbulence models. The results showed that the FBM model had least er2 r or in pr edict ing ex ternal char acteristics under non2desig n conditio ns, especially in the flow field under small flow conditio ns. The averag e lift err or w as 11 19% , and the aver age efficiency err or w as 51 31% , respectively . T he accur acy of FBM in predicting cav itation vo lume and g as fr actionw as hig her than o ther thr ee turbulence models, w hich w as mostly close to the obtained ex peri2 mental r esults. In the initial stage of NPSH = 51 25 m cavitat ion, the main f requency o f pr essure pulsat ion on the blade w as loca2 ted at f n, and its frequency w as do ubled, while la rge number of low2fr equency amplitudes appear ed at the pressur e monitoring po int on the suction surface of the blade due to the influence of cav itation collapse. The pr essure pulsatio n at the outlet of the guide vane w as influenced by the flow pattern on the back of the g uide blade.

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