Parameter equation study for screw centrifugal pump

Compared with the general centrifugal pump, the screw centrifugal pump has a spiral radial impeller and opening flow passage. The impeller inlet is a spiral blade and outlet of blade looks like to mixing-flow pump blade. Its special structure made the screw pump not only having spiral propelling effect but also having centrifugal effect, therefore the screw centrifugal pump has both the merits of screw pump and centrifugal pump. According to the structure characteristics of screw centrifugal pump, character of flow-field inside the pump and projection drawing on foundation with one-dimension, the regularity for change of pitch in the variable-pitch parametric equation group is given in this paper. And the variable-pitch parameter equation group of the screw centrifugal pump is perfected. Using the parametric equation, to segment streamline dots on axial plane for designing screw centrifugal pump blade is facilitated, which has important meaning to the CAD, numerical simulation of three-dimension flow-field and improve performances of screw centrifugal pump