Influence of design parameters of discharge passage on the performance of shaft tubular pumping system

Abstract

Shaft tubular pumping systems with straight discharge passage are more widely adopted because they possesses many advantages such as easier installation of pump sets, better ventilation for motor and transmission devices, open access to inspect pump sets and lower cost for maintenance. The design parameters of a straight discharge passage will directly affect hydraulic loss and energy performance of the shaft pumping system. The optimal hydraulic design of discharge passages is carried out under the guideline of Pump Station Design Code to satisfy optimal design objectives. Computational fluid dynamics is applied to simulate the internal flow of a shaft pumping system the influence of its design parameter on the system performance is investigated. Keeping the shaft and suction box unchanged, six discharge passage design schemes with different length and outlet width are compared based on CFD to analyze the internal flow fields and their energy performances are predicted. The computed results indicate that when the outlet width of discharge passage is fixed, the longer the discharge passage, the better the internal flow fields with smaller backflow and vortex zone inside the passage. When the length of discharge passage is determined, the axial velocity distribution uniformity and bias angle in the outlet section will vary with the value of the outlet width. Optimal hydraulic design of discharge passages can achieve better internal flow and higher pumping efficiency.