Hydraulic Design For Impeller Of High Specific Speed Mixed-flow Pump And CAD System's Research

With the extensive application of computer, Computer Aided Design (CAD) technology have been gotten a lot of development in domestic and foreign. Useing of advanced CAD technology, not only ensured the quality of the product design, but also greatly shortened the design cycle and improve the design capability to achieve the design optimization. CAD technology has been widely used in various fields and also has been fully recognized in the pump manufacturing industry. Although our country's pump CAD technology has also made certain progress, but because starting late, the total application level is also quite low, specially in the research of high specific speed mixed-flow pump.In this study,author combined mixed-flow pump recent good results,implemented the further development with Visual Basic programming language and AutoCAD graphics platform, researched a CAD system for impeller of high specific speed mixed-flow pump hydraulic design in the Windows environment, roughly realized of the computer-aided design of mixed-flow pump. The CAD system has used the object-oriented design idea, a straightforward, concise and standard human computer-interface is designed for the system, which makes the operation of the system , greatly improved the efficiency of hydraulic design.Combining design experience of one-dimensional theory for mixed-flow pump to plan axial surface projection of the impeller, adjust the shape of the impeller blade axial parameters (pre-plate arc, arc after the cover, while of the import and export, etc.); based on the two-dimensional theory(Ω3 =0)to draw streamlines, calculated meridional velocity d- istribution by streamline ineration, fited the streamline equation with the spline function, adjust the streamline shape parameters (import and export of leaf angle, leaf while the import and export, Vu r distribution, etc.) in order to make the streamline change light to be suitable; drawed blade shape by point-by-point in tegration; thickened blade in axial surface and make lesves round from head to end in the planar projection; generated the discrete points'three-dimensional coordinates of the blade surface finally.Using CFD modeling to predict pump performance, test the reliability of the procedure.The effects of several parameters on the designed impeller shape are also discussed,including hub/shroud radius ratio,velocity moment distribution function on the meridional stream line,position of blade inlet and outlet edge.Author's work builds up the foundation for the deep research on mixed-flow pump.