Abstract
Demands for higher performance of axial flow pumps have led pump designers to consider the creative strategies for the new type. As a solution, contra-rotating rotors might be applied to a pump. Comparative experiment were conducted for two types, consisting of contra-rotating rotors and a rotor and a stator respectively, which were designed under the same specifications of pump head, flow rate and rotor specific speed. The measured pump performances and flow distributions are shown and the advantages of using contra-rotating type are clarified as follows. Contra-rotating type is superior in pump efficiency and cavitation performance in range of partial flow rates to conventional one though the specified pump head and maximum efficiency are not satisfied at design point in the case of contra-rotating test rotors. Results demonstrate that the rear rotor design is important to improve the pump efficiency.
