Research On The Flow And Hydraulic Performance In The Primary Impeller Of A Multi-Stage Vertical Barrel Pump

The multi-stage vertical barrel pump is mainly used for transporting material which evaporate easily and is sensitive to temperature. Because of it’s high cavitation performance, high efficiency, good reliability, long life, low noise and small cover area, the multi-stage vertical barrel pump is widely used in various industries. At present, the study of the multi-stage vertical barrel pump is mainly focused on the theoretical research and experimental research, but lacking of the analysis and research on numerical simulation of the internal flow. Primary impeller is an important hydraulic component to a multi-stage vertical barrel pump. A multi-stage vertical barrel pump with double-suction primary impeller and two inducers was chosen as the model, and because it can meet the requirements of the cavitation performance, thus improve the hydraulic performance of the pump become the primary task of the research. This research has chosen the primary impeller of a multi-stage vertical barrel pump as the research object, and using the method of numerical simulation to study the influence of the geometric parameters of primary impeller on the flow and hydraulic performance. The main research contents are as follows:(1)CFD simulation technique theory of a multi-stage vertical barrel pump and the basic procedure of CFD simulation were introduced systematically, including pre-processing such as computational domain modeling, mesh generation and boundary conditions setting; basic theory and option of simulation such as governing equation, discretization scheme, solving method; post-processing such as prediction of pump performance.(2)Based on CFD, this research has observed and analyzed the numerical simulation of 300LDTN-200 multi-stage vertical barrel pump. The 300LDTN-200 multi-stage vertical barrel pump was simulated at different operation points to achieve the hydraulic performance and the flow pattern.(3)The influence of primary impeller blade number of a multi-stage vertical barrel pump on hydraulic performance has been studied. According to the results of numerical simulation, head, efficiency and performance curve can be achieved. The influence of blade number on head and efficiency of a multi-stage vertical barrel pump was gotten by analysing the H-Q and η-Q curves.The result shows that it had a most appropriate blade number which is 5 when other parameters were not changed.(4)The influence of primary impeller wrap angle of a multi-stage vertical barrel pump on hydraulic performance has been studied. Pressure in impeller flow passage of different wrap angle was analysed according to the pressure contours.the influence of wrap angle on hydraulic performance of a multi-stage vertical barrel pump was analysed from the shape and the rate change of the curves. There was a most appropriate wrap angle which made efficiency maximal. To the 300LDTN-200 multi-stage vertical barrel pump, when the wrap angle was 130° and other parameters were not changed, efficiency was the maximum.(5)The influence of primary impeller inlet edge width of a multi-stage vertical barrel pump on hydraulic performance has been studied. The result shows that, the influence of primary impeller inlet edge width on the flow was gotten by analysing the pressure contours of different primary impeller inlet edge points. According to the changes of H-Q and η-Q curves, influence of primary impeller inlet edge width on hydraulic performance was analysed.(6)In order to check the reliability of CFD simulation, a group of pump performance tests about model pump and the retrofit pump with blade number is 4 were carried out. The comparison shows that the prediction error is within 5% when pump works at the range of 0.6QQopt-1.4Qopt and test results were very close to the simulation results, and the feasibility of improving the hydraulic performance by changing geometric parameters of the double-suction primary impeller of a multi-stage vertical barrel pump.