| Effects of impeller type on pump performance in Double-suction centrifugal pump with a single high flow are widely used in pump products. In actual operation, the efficiency of Double-suction centrifugal pump made in china is10%less than developed countries at present.Therefore, in order to improve its hydraulic performance, it is necessary to research and reform its technical.The Double-suction centrifugal pump of type1200S56is the research object in this paper.Numerical simulation of internal flow within Double-suction centrifugal pump is carried out, simulation results and experimental results are compared. It is finally proved that numerical calculation is feasible for researching pump performance. The appropriate selection of blade numbers in Double-suction centrifugal pump is an important way to improve pump performance. Models of impeller passages with different blade numbers are developed; usually the original design of blade number is6, while the blade numbers of new impeller are5and7. The models combined with other developed flow components are assembled, and carried out numerical simulation by using CFD and results are analyzed.A conclusion is drawed through the research1. With the increase of blade numbers, the head of Double-suction centrifugal pump also increases. Under the condition of the same blades in Double-suction centrifugal pump, head gradually decreases with the increase of flow, and efficiency increases too. To some extent, it will reach the maximum on design condition, then start to decrease gradually.the efficiency is different in different blade numbers. The efficiency is higher with6blades than5and7. Because the more numbers of blades, the stronger control over flow of fluid is produced. If there were too much blades, the flow area of impeller would be too small, exclude coefficient would be great. They are conducive to improve pump performance.2. When the blades are6, the pressure distribute better on the pressure surface than the suction surface. The area of negative pressure is smaller on design condition; there is no scattered low-pressure area in the inlet of blade and the low-pressure is also smaller in high flow. Flow condition of6is better than the other two kinds of blade numbers. The pressure in chamber distributes more uniform, so it is good for the structure of the chamber. At the same time, impeller type also has important effects on pump performance. The paper will make steady numerical analysis of the impeller with bilateral blades staggered and studies the impeller type.conclusions are:1. Heads of two kinds of impeller are all decrease with the increase of flow. Impeller with bilateral blades staggered has higher head than symmetric impeller in low flow and it is just the opposite in high flow.while the head is higher than staggered impeller on design condition. Efficiency of two kinds of impellers is also increase with the increase of flow and reaches to maximum on design condition, but it is lower than staggered impeller on low condition and high flow instead. In addition, efficiency of staggered impeller is higher on design condition. Impeller with bilateral blades staggered is the best choice on design and high flow.2. The distribution of pressure of the two kinds of impeller is basically identical on design condition. The area of low pressure is large in symmetric impeller. However, the pressure of outlet is relatively higher; the area of low pressure is smaller in the inlet of impeller. In these ways, staggered impeller is better than symmetric impeller, because the low pressure area prone to cavitations. There is a local minimum pressure dispersedly in the inlet of impeller. So it’s very bad for pump operation. |
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