Research On A New Suction Chamber To Improve Cavitation Performance Of Centrifugal Pump

Centrifugal pump at runtime may reduce the absolute pressure of impeller inlet, which may lead to cavitation phenomenon when local pressure is lower than the vapor pressure of fluid. Cavitation damage may give rise to performance reduction of centrifugal pump as well as vibration, noise and other issues. From the current research, the cavitation performance of most centrifugal pumps still can not meet the real needs. Therefore, it is necessary to research a effective way to improve cavitation performance of the centrifugal pump. This paper analysis of the mechanism of cavitation through theory, combined with injection technology of the injection pump, putting forward that an ejector device add to the suction chamber in order to improve cavitation performance.The influence of ejector device structure on the performance of centrifugal pumps was researched based on CFD simulation in order to optimization design of the new suction chamber struction. The main works and results are as follow:1. The cavitation performance of the IS100-80-160centrifugal pump was simulated based on CFD. The three-dimensional models of centrifugal pump were built based on Pro/E, these models were meshed by Gambit, and the cavitation performance, hydraulic performance and mechanism of cavitation were steady simulated based on CFX.2. The mechanism of cavitation was analysed through theory, combined with injection technology of the injection pump, putting forward that an ejector device add to the suction chamber in order to improve cavitation performance, and the feasibility of the method was proved.3. The influence of ejector device structure on the performance of centrifugal pumps was researched based on CFD simulation in order to optimization design of new suction chamber struction. The results show that(1) With the outlet diameter of injection pipe increases, NPSH of centrifugal pump at first decreases and then increases, head and efficiency decline. The optimum outlet diameter of injection pipe is3mm.(2) With the angle of injection pipe increases, NPSH of centrifugal pump increases, head and efficiency decline slightly. The valid range of the spraying angle is10°～30°.(3) With the injection pipe increases, NPSH of centrifugal pump at first decreases and then increases, head and efficiency decline. The optimum number of injection pipe is8.(4) With the diameter of lead back pipe increases, NPSH of centrifugal pump at first decreases and then increases, head and efficiency decline. The valid range of the lead back pipe diamete is15～20mm.4. The optimized hydraulic model was compared with the original model, the result show that NFSH of the optimized hydraulic model is lower, maximum reduction is0.72m, cavitation performance of the centrifugal pump increased33.49%, improvement is very impressive. But the head and efficiency of the optimized hydraulic model slightly decrease, less than5%.5. Experiment of optimized model and original model were carried out, the trend of simulated performance curves were consistent with the experimental data, and the deviations were no more than7%. At the same time, the accuracy of numerical simulation was verified.