No abstract

No abstract

Abstract. Secondary flow is one of the main reasons for low efficiency in double suction centrifugal pump. In a 3-D inverse design method, the pump blade could be designed by a specified loading distribution to control the flow field in pump. In order to study the influence of loading distribution on secondary flow of a double suction centrifugal pump, the external characteristics and the internal flow field of the pump with three kinds of loading distributions are analysed by using CFD approach. According to the simulation results, it is found that the form of fore-loading distribution at shroud and aft-loading distribution at hub could improve the optimal efficiency and broaden the high efficiency area of the pump. Furthermore, the secondary flow in impeller exit region and volute could be significantly suppressed if the slope of loading distribution curve of shroud is set to be -0.7. 1.IntroductionDouble suction centrifugal pumps are widely used in water diversion, irrigation, drainage and water supply engineering. However, pump sometimes operates at partial design conditions and results in low efficiency. At this condition, the secondary flows including the backflow and vortex present in the pump chamber [1]. Therefore, it is a challenging issue to control the secondary flows inside a double suction centrifugal pump.The 3-D inverse design method is a new design tool in which the blade loading distribution has to be specified [2]. The flow field in a pump could be controlled by specifying a suitable blade loading distribution, so it is necessary to study the influence of the blade loading distribution on suppression of secondary flows in a double suction centrifugal pump.The blade loading distribution curve is a three-segment curve [3][4] consisting of a parabolic curve and a straight line section followed by another parabolic curve in the 3-D inverse design method. Zangeneh [5] designed a mixed-flow pump impeller by using the inverse design method with a small slope of the straight line, this kind of loading distribution improved the backflow and wake-jet of impeller exit. Ashihara [6] improved a centrifugal impeller by using aft-loading distribution at shroud and hub, the results showed that pump inlet suction performance was improved, but the backflow of impeller exit was obvious. Zangeneh [7] designed a centrifugal impeller by using two kinds of loading distribution, the first is fore-loading distribution at shroud and hub, and the second is fore-loading distribution at shroud + aft-loading distribution at hub. The results showed that the second loading distribution is better than former for both the backflow of impeller inlet and exit. To sum up, the form of aft-loading distribution at hub could helps to improve the suppression of secondary flows in pump,

No abstract

No abstract