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The impeller is the core component in the axial flow pump apparatus , and the entire apparatus through which the mechanical energy transfer water , so that parts of the increase in the energy of the water , the impeller directly determines the performance of the pump . At present , China is building a lot of water diversion and irrigation and drainage pumping stations mostly vane pump . Therefore , the structure parameters of impeller pump performance has a practical significance . Based on RANS equations and RNG k? Ε turbulence model , geometric modeling software ICEM modeling and meshing TurboGrid Axial Flow Pump , and on this basis, with a commercial three-dimensional fluid software CFX device within the three-dimensional incompressible flow field numerical analysis , calculation of the internal and external characteristics of the different options ( different leaf thickness , different blade angle and different shape wheels ) device . After the post-processing of the CFX-Post drawn: (1) the blade thickness , and at the same flow rate , the pump head and shaft power increases, the maximum efficiency point is offset to the large flow , and the maximum efficiency point is improved . (2) blade thinning leaves exclusion coefficient becomes small , the flow area increases , in the same flow , axial flow velocity decreases , the angle of the flow stream , according to the inlet velocity triangle seen smaller . Of the airfoil , the equivalent of water larger angle of attack , the head and the shaft power increases . So the blade angle becomes large with the blade thinner due to changes of the head and shaft power is similar . (3) in the same flow , the blade thinning, increase in the pressure of the pressure surface of the blade , resulting in the increase of the impeller lift , while small changes in the pressure of the suction surface of the blade , a slight increase , making the cavitation improved performance . (4) the hub becomes spherical by a cylindrical , because it is too water cross section is reduced , relatively speaking, i.e. exclusion coefficient of the blade becomes larger , and the mechanism similar to the blade thickens , which generates the same effect , i.e. the shaft power and the lift change efficient point is offset to the large flow rate , and the maximum efficiency point increase .
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