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In recent years, CFD technology has been widely used for theoptimum design of fluid machinery in developed country. In our country,the research and applications of CFD technology are still preliminary, andit needs a further development on the application of CFD technology todesign fluid machinery more efficiently. Based on the CFD technology, anumerical method is developed to predict performance, analyse energylosses and flow characteristics in a centrifugal pump, and the detailedflow field at different operating conditions is also revealed by thismethod.In the paper, some CFD theories are introduced firstly, and thecontrol equations in rotating reference frame used to the simulation of theflow field of a centrifugal pump are deduced. A new kind ofcomputational domain structure, that is, the front and back chambers andthe seal clearance should be involved in the computational domainbesides the impeller passages and volute casing, is developed innumerical simulation. The following grid-generation method is selected,the structured grid is used in front chamber, back chamber and sealclearance, the unstructured grid is used in the volute casing and thecomplicated impeller passages. Through the comprehensive comparisonsbetween simulating datum, in different grid number and turbulencemodels, and experimental datum, the suitable gird number and turbulencemodel are confirmed for the centrifugal pump model. The flow are also simulated at different relative positions between blade and volute tongue,it is found that the different relative positions between blade and volutetongue can influence the numerical simulation results, and the regularitiesbetween them are analyzed. Based on the method of numerical simulation,the simulating results show that the computational domain structure usedby the authors is better, through the comparison between the simulatingresults derived from two different kinds of computational domains and theexperimental results. Within the flow range from 0 to 1.35Qopt, thecomputational performance curves such as head, shaft power andefficiency agree well with the tested curves. Due to the completecomputational domain, a full prediction can be made too, such as the diskfriction loss, volume loss and hydraulic loss existing in a centrifugalpump. The losses existing in each through-flow part are predicted bycorrecting the disadvantage of traditional method, the computationalresults shows that the losses in the impeller passage and volute casing arethe majority of the whole losses, and the energy losses regularitiesaccording with flow rate are revealed, too. Influenced by the varyingcross-section area of volute casing, the flowrates and energy losses ineach impeller passage are quite different, the losses in the passages nearthe volute tongue are much more than the others, and the liquids comingfrom the passages most near the volute tongue are the major componentsthat produce the disk friction loss and volume loss. By numericalsimulation, some adverse phenomena are found, such as jet-wakestructure, secondary flow, impact phenomenon, dead water zones, and soon. The distribution regularities of total pressure, static pressure andvelocity are also analyzed in each through-flow part. It provides importantguidance for the optimum design of a centrifugal pump.
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