Numerical and Experimental Investigation of Performance and Reliability in New Reverse Osmosis Seawater Desalination High Pressure Pump

Abstract

In order to reduce the investment cost and energy consumption of high pressure pump in Seawater Reverse Osmosis desalination project, a new type of multistage high pressure centrifugal pump with two ends of water-lubricated bearings supporting and axial suction was proposed after analyzing the structural feature of the high pressure pump. The numerical simulation method and mesh quality was improved, the pump performance was predicted and optimized. The relationship of the critical speed and logarithmic decay rate with stage was analyzed, and the relationship between the stage and efficiency of multistage pump was combined to analyze the optimal selection for the impeller stages of multistage pump. The experimental results of axial thrust were used to modify theoretical formula of axial thrust and accurately predicated the axial thrust at different operating conditions. A new balancing device with less leakage fluid, high balancing sensitivity and proper restoring force was designed to improve the reliability of axial thrust balancing device. The experimental results show that the efficiency of the new multistage high pressure centrifugal pump is 83.07% which is increased by 3.07 percents when the design flow rate is 220m3/h, and total Head is 620m. The new multistage high pressure centrifugal pump has been applied in the Chinese Zhoushan seawater desalination project, which runs with high efficiency and stability.