Numerical analysis on velocity field of water-jet pump under non-uniform inflow
JIN Shibin1, CAO Puyu2, WANG Yang2
1.Wenling Bureau of Quality Supervision and Inspection, Wenling, Zhejiang 317500, China; 2.National Research Center of Pumps, Jiangsu University, Zhenjiang, Jiangsu 212013, China
Abstract:To research the correlation between non-uniform inflow and the hydrodynamics of water-jet pump, the outflow velocity field in the intake duct was analyzed by the CFX-Post software. The velocity field of non-uniform outflow was selected as the inflow boundary condition in the process of simulation, and the hydrodynamics of water-jet pump was achieved. Then the comparison of hydrodynamics between non-uniform and uniform inflow conditions was carried out. The results show that the hydrodynamics of water-jet pump in the non-uniform inflow condition is lower than that in the uniform inflow condition. With the non-uniformity of the inflow field increasing, the decreasing amplitude of the head and efficiency is increasing. According to velocity components of non-uniform, the reason that the pump hydrodynamics reduced in the non-uniform inflow condition was analyzed. Results show that the traditional design method can not meet the working requirements, and the correlation assumptions are unavailable to the condition of non-uniform inflow. The existence of inlet pre-swirling in the non-uniform inflow field is against the "no pre-swirling" hypothesis, so the angle of attack and the lift coefficient of airfoils decrease. The interaction between axial and radial velocity in the non-uniform inflow field results in the nonlinear distribution of the meridional velocity and circulation. The circumference independence assumption is invalid owing to the change of radial velocity. The non-uniform inflow also impacts the field of blades, which is concentrated at the shroud. The secondary circumfluence blocks the flow passages, and weakens the flow capacity of the water-jet pump. Meanwhile, it contributes to the deviation curve of blade loading at the shroud, and impairs the working ability of the water-jet pump. In conclusion, the non-uniform inflow is the major reason for the decrement of propulsion efficiency,therefore the non-uniform inflow condition should be considered during the process of water-jet pump designing.
金实斌, 曹璞钰, 王洋. 非均匀进流下喷水推进泵进流速度场的数值分析[J]. 排灌机械工程学报, 2016, 34(2): 115-121.
JIN Shibin, CAO Puyu, WANG Yang. Numerical analysis on velocity field of water-jet pump under non-uniform inflow. Journal of Drainage and Irrigation Machinery Engin, 2016, 34(2): 115-121.
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