| The main flow passage component of high specific speed mixed flow pump is impeller. Impeller is an important part for transforming energy. According to the requirements of different flow patterns,high specific speed mixed flow pump with different impeller forms can be designed. In this paper, three kinds of flow patterns methods were adopted,which were the distributions of up jog circulation,linear circulation and the convex to the below circulation.Whether pressure distribution inside the pump is reasonable (uniform pressure gradient),and the velocity vector is smooth (reflux and secondary flow),and flow-line is uniform and smooth, numerical efficiency is high, it is the pump problem the designer has always been very concerned about. With the computer technology and computational fluid dynamics such as the rapid development, it is possible to simulate the internal flow field of mixed-flow pump by CFD , and has become an important design tool. In this paper, full three-dimensional numerical simulation of high specific speed mixed-flow pump internal flow field was done and thus the velocity vectors and pressure distribution properties was got, and it provides a reliable basis for the design of impeller.Four flow passage components of flare tube inlet, impeller, guide vane body and elbow pipe were coupled together. And binary theory were adopted to design the impellers and there were three models designed. The main flow characteristics were obtained by simulating different flow patterns, and analyzed the interior flow in each model, all the results above discovered interior flow for high specific speed mixed-flow pump and provided the basis for performance improvement. The main work of this paper includes:1. A brief description of the mixed-flow pump development at home and abroad and the designed methods of it were given. Based on it, according to the design parameters, three pump models (Up jog circulation ,linear circulation and the convex to the below circulation) were designed. The corresponding guide vane bodies were designed,too;2. The Pro/Engineer software was applied to design the whole pump (including flare tube inlet, impeller, guide vane body and elbow pipe). Three models were designed;3. Large eddy model and numerical simulation related software were briefly introduced, and Ansys CFX pretreatment software ICEM-CFD was used for meshing the whole calculated region;4. k-εModel provided by Ansys CFX was adopted, and finite volume method was used to enclose the N-S equation. The numerical simulation of the 3-D interior incompressible, steady, turbulent flow field in the 3 mixed-flow pumps were carried out at different operation points,and the flow field distribution was obtained by simulating internal; Three-dimensional incompressible unsteady turbulence flow field for the first model was done, and the flow field distribution was obtained;5. The head, power and hydraulic efficiency prediction calculation method and formulations were introduced. Performances of three models were predicted. At last, the predicted performance curve of model 1 was compared with the experimental performance curve.By the former works, the main conclusions are shown as following:1. CFD method is convenient and fast, and it can describe the flow field of high specific speed mixed flow pump well;2. Head of point of maximum efficiency and effectiveness, as well as efficient zone width of high specific speed mixed-flow pump of the distribution of different circulation have their own characteristics, so that according to different needs, Designers use different kinds of circulation distribution to design the pump;3. The unsteady numerical simulation revealed that there is apparent rotor-stator interaction which showed periodic rule between the impeller and guide vane body.
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