Numerical simulation of water supply pipe position to intake of small-sized pumping station
CHEN Yichun1, ZHANG Hui1, DAI Sheng1, GAO Jun1, XIA Bin2
1. Zhenjiang Water Company, Zhenjiang, Jiangsu 212000, China; 2. National Research Center of Pumps, Jiangsu University, Zhenjiang, Jiangsu 212013, China
Abstract:To explore the flow instability in an intake of secondary water supply pumping station and study effects of water supply pipe position to the intake on flow patter in pump suction pipes, Ansys-CFX fluid simulation software was used to calculate the three-dimensional steady turbulent flow in the intake. The fluid domain includes the water supply pipe, intake, and a few pump suction pipes. In the simulations, the water supply flow rate was kept the same, but the supply pipe had two positions. Based on the obtained flow condition in the pump suction pipes and the hydraulic loss in the suction pipes as well as the velocity distribution in several cross-sections, an improved design was proposed. The flow condition in that design was checked accordingly. The results show that vortex and flow turbulence exist, and the uniformity of axial velocity is poor as well as the flow average derivation angle is larger in the pump suction pipes in pump intake A, where the water supply pipe is opposite to suction pipe #5, suggesting an unsatisfactory inlet flow condition to the pumps. When the water supply pipe position was altered to the left and right sides by 1.375 m, the hydraulic loss in suction pipe #5 was only 3.301 cm and 3.258 cm, respectively, in comparison with 6.579 cm loss in the original design. Furthermore, the uniformity of axial velocity increased, and the flow average derivation angle decreased, showing an improved inlet flow condition. Therefore, in order to improve the flow instability at pump inlet, the water supply pipe to the intake should prevent from being rightly against a pump suction pipe.
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