Quasi-3D inviscid flow analysis of contra-rotating axial flow pump

Contra-rotating axial flow rotors, which have been used as a ship propeller and a fan, might be prospective as a pump if higher performance and wider operation range would be obtained than the conventional type of axial flow pumps. Pumps of contra-rotating and conventional types were designed under the condition of the same rotor specific speed, N_s= 1500, by using a conventional method based on empirical data. In the present paper, before starting the experimental works, the pump charac-teristics and flow behaviors of both types are examined numerically by using a quasi-3D inviscid flow analysis, consisting of a streamline curva-ture method in the meridional flow and a blade surface singularity method in blade to blade flow. The selected design parameters for contra-rotating rotor blades are discussed from the calculated results. Then the advantages of using the contra-rotating type are clarified by comparing the pump performance and flow distributions around the blades with those of the conventio al type.