Purpose The paper aims to investigate the clocking effect on a centrifugal pump with inlet guide vanes (IGVs). Design/methodology/approach The paper uses a computation fluid dynamics (CFD) framework to solve the unsteady flows in a centrifugal pump with inlet guide vanes. The relative position between the stationary vanes and the stationary volute tongue is defined as the clocking position when IGVs inside the suction pipe rotate along the circumferential direction. Findings The results show that clocking positions have little effect on the pump head and efficiency, however their influences are obvious for the pressure fluctuation and flow field in the centrifugal pump. The maximum difference of pressure amplitude at dominant frequency reach up to 28% on the monitoring point V8 at different clocking positions under design flow rate. For the large flow rate, the clocking effect on flow field and pressure fluctuation in centrifugal pump is similar to that of design flow rate. However, the clocking effect is nearly negligible at partial flow rate, because there are reverse flows around the tongue tip and obvious vortexes forming and developing in the impeller. Those complex phenomena interacting in the centrifugal pump make the clocking effect less evident. Originality/value The numerical investigation reveals the clocking effect on a centrifugal pump with inlet guide vanes, which also valuable for the stable operation and optimal design of centrifugal pumps.

Optimization design of centrifugal pumps involving multiple parameters and objectives is a complicated research topic. The orthogonal method is introduced in the present study to find a high efficiency and low cost way in the optimization process of a centrifugal pump. A orthogonal table designation L16(45) is established, in which 16 individuals of impellers are generated with five design parameters: blade wrap angle, blade angles at impeller inlet and outlet, blade leading edge position, and blade trailing edge lean varying at four levels for each parameter. To realize the multiobjective optimization of both pump efficiency and cavitation performance, an integrated factor considering the weight of two objectives is introduced. On the basis of validated computational fluid dynamics (CFD) technique, the range analysis gives the influence order of five parameters and also determines the value of each parameter. Finally, the optimal centrifugal pump is obtained with remarkable superiority on the efficiency of 3.09% rise and cavitation performance of 1.45 m promotion in comparison with the original pump.

View the article online for updates and enhancements. Related contentCavitation performance and flow characteristic in a centrifugal pump with inlet guide vanes L Tan, L Zha, S L Cao et al.-Influence of blade angle distribution along leading edge on cavitation performance of a centrifugal pump Y Xu, L Tan, S L Cao et al.

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In order to predict cavitation performance drop of the cen trifugal pump, the RNG K-8 turbulence model and the mass transport cavitation model are applied to simulate the cavitation flows in a centrifugal pump at different flow rates. The influence of condensation coefficient of the mass transport cavitation model on numerical simulation is analysed. According to the calculation result, the value of condensation coefficient is modified. The calculated variation of pump head and efficiency at different flow rate agrees well with the experimental data. The results demonstrate that the numerical model and method can accurately predict the cavitation flows in a centrifugal pump. The cavitation flow fields in the centrifugal pump are revealed. The results show that the cavity bubbles firstly appear in the blade suction side and then develop to the middle of blade-to-blade channel. When the cavitation bubbles increase and then block the normal flow in the impeller, the pump head gradually drops. The detailed evolutions of cavitation structure in the centrifugal pump impeller are presented to provide beneficial references to the centrifugal pump optimization design.