Water pump characteristic curve obtaining method and system based on three-point method

The invention discloses a water pump characteristic curve obtaining method and system based on a three-point method, and relates to the field of hydraulic design. Establishing a proportional relation between the lift and the rotating speed; establishing a proportional relation between the shaft power and the rotating speed; establishing a proportional relation between the rotating speed and the frequency; mathematical structures of the flow-lift curve under different frequencies are obtained; acquiring mathematical structures of the flow-shaft power curve under different frequencies; obtaining a second flow-lift curve under the condition of a second frequency f2; obtaining a second flow-shaft power curve under the condition of a second frequency f2; a first flow-lift curve is obtained; and obtaining a first flow-shaft power curve. By arranging the proportional relation establishing module, the second data processing module, the first data processing module and the function relation obtaining module, the compl