Study on Similarity of Pump Blade Adjusting Performances

Through analyzing the change in velocity triangles at the inlet and exit of pump impeller with blade adjusting, and the flow behaviors in the pump passage the pump blade adjusting formulae were derived which reflect the similarity of flow and pumping head with the blade angles adjusted. Based on the experimental data of pump performances a mathematical model was developed to calculate the flow index and head index of the formulae. The objective function is a minimized the least square sum of the errors of the formulae’s calculation and the test data. The formulae were applied to three model pumps. The results show that the errors between calculated and measured data are 0.0228, 0.0116%, 0.0123 respectively, and all the head-flow curves (H-Q) and the power-flow curves (P-Q) agree well with the measured data from model test. Therefore, the derived formulae are featured with good similarity in pump performances for change blade angle, which can be applicable to the performances conversion and prediction of pump with blade adjusting.