Hydraulic Design of Non-Overload,Super-Low Specific Speed Centrifugal Pump

For specific speed ns30, the pump is generally not designed in centrifugal type due to low pump efficiency and steep brake power curve which results in overload easily. For the first time in the field, the authors study the non-overload design method for super-low specific speed centrifugal pump. With ns = 23 miniature pump as an example, the selection principles of main impeller geometrical parameters such as impeller diameter D2 , exit width b2, discharge angle β2, vane number Z and vane rapping angle ψ are discussed. The drawing method of plane flow passage is also given. The test results and performance characteristics are introduced. The study shows that with reasonable design, the pump with ns30 can be developed with higher efficiency and non-overload characteristics.