Numerical Simulation Of Interior Flow Field In The High-Specific-speed Double-Suction Centrifugal Pump And The Analysis Of Impeller-Trim

As a kind of general machinery, centrifugal pump is widely used in many diversefields such as industry and agriculture, however, the running pumps in our countrymostly have low efficiency and poor reliability, in order to analysis the influencingfactors of pump’s performance, explore and analysis the inner flow condition ofcentrifugal pump is necessary. Computational Fluid Dynamics as one of the newmethods that developed with the development and spread of computer technology canobtain the inner flow field of the centrifugal pump quickly and expediently, also it cancalculate the performance parameter of centrifugal pump accurately, because of theseadvantages, CFD become widely used in the design and study of pumps. As one of themost important type of centrifugal pumps, double-suction centrifugal pump has manyadvantages in structure and performance, so it has a great significant to explore theinner flow field of double-suction centrifugal pump based on the CFD method.Impeller-trim as one of the most important approach to implement energy-savingreform of centrifugal pump is widely adopted in engineering practice, but it will exista large deviation when confirm the high-specific-speed double-suction centrifugalpump’s cutoff size of impeller if use the existing formula for the impeller trim ofcentrifugal pump, so it is necessary to analysis the influence of impeller-trim on theinner flow field and the performance of centrifugal pump for the sake of determine theimpeller trim size more accurately.In order to reveal the internal flow condition in detail and analysis the influenceon the performance and the flow field distribution of impeller trim, this paper maincompleted the following work:1. The modeling of three-dimensional flow channel of double-suction centrifugalpump based on Pro/E.Through the analysis of the basic theory and motion equation, three-dimensionalmodel of the whole flow channel of double-suction centrifugal pump that containimpeller channel,suction chamber channel, volute channel and the pipeline in front ofsuction chamber and in the back of volute were built based on the software of Pre/E.2. Mesh distribution of the three-dimensional flow channel of double-suctioncentrifugal pump and the numerical simulation.Mesh distribution was accomplished based on the software of Gambit, thenecessary mesh number was discussed. Numerical simulation was carried out based on the software Fluent, the inner pressure field, velocity field and trace details ofcentrifugal pump were obtained.3. Performance prediction and test analysis of double-suction centrifugal pump.The centrifugal pump’s performance curves were predicted according to thenumerical result, also, performance test about the same pump was carried out.Through the contrastive analysis of predicted result and test result, made a judgmentabout the applicability of numerical method.4. Numerical simulation about the effect of impeller-trim on the performance ofhigh-specific-speed double-suction centrifugal pump.The effect of impeller-trim on the inner pressure field, inner velocity field, innertrace details were discussed through the impeller-trim numerical simulation of threehigh-specific-speed double-suction centrifugal pump. In addition, the effect ofimpeller-trim on the Head, shaft power and efficiency were obtained according to thenumerical result. Finally, impeller-trim index in the optimal operating condition wasdiscussed.