Head calculation and amendments for centrifugal pumps at shut off condition

How to calculate head of the centrifugal pump at shut off condition has been a difficult problem. The existing methods to compute head of centrifugal pump at shut off condition and their detail formula were introduced. Based on the practical calculation of 34 centrifugal pumps, the precision and application range of all methods were analyzed. The analysis indicates that the result of Euler method is theoretical head of centrifugal pump at shut off condition and its deviation is more than 60%. The precision of Throne method is the highest and its average deviation is 4.29%. The precision of Stirling method is the lowest and its average deviation is 11.3%. The specific speed was chosen as independent variable and non-linearity regression analysis was used to amend the seven methods. The revision formula and confidence parameters were presented. At last, 5 centrifugal pumps were chosen to check up the regression analysis results and the practical application indicates that the precision of the modified formula is improved obviously and can meet the engineering requirement.