Turbulent flows in tubular pump and fluidstructure interaction characteristics of impeller
(1.College of Water Resources & Civil Engineering, China Agricultural University, Beijing 100083, China; 2.College of Energy and Electric, Hohai University, Nanjing, Jiangsu 210098, China; 3.State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China)
Abstract:The RNG k-ε turbulence model and the Ansys Workbench software were used to numerically investigate internal flows in a frontpositioned shaft tubular pump and fluidstructure interaction in its impeller. The simulated performances under different operation conditions are consistent with experimental data.Even though the calculated head is higher and the efficiency is lower than the experimental data, their errors are less than 10%. The velocity and pressure of fluid are uniformly distributed in the whole passage of the pump except in the discharge passage. The spiral streamlines in the front of the discharge passage show that the fluid has a residual velocity circulation after it leaves the vaned diffuser. At the design flow rate, a minimum pressure is seen on the suction surface of blade near the blade leading edge, where cavitation will be apt to occur. In addition, a static structural analysis on the impeller was carried out based on oneway fluidstructure coupling method and the stress and deformation of blades were predicted under different operating conditions. The results show that at the design flow rate, there is a maximal equivalent stress on the pressure surface of blade but at the junction of blade and hub. The total deformation of blade increases with radius, and there is a maximum deformation near the impeller tip. The calculated results will provide a reference for optimization design of tubular pumps.
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