Sensitivity Solution of Off-Design Conditions in Centrifugal Pump

Abstract

Centrifugal pumps are most widely used pumps in industry and household usage for fluid flow. During usage of pump, pump speed and discharge may need to be varied. Also during continuous usage of pump, different physical defects may arise. These conditions would create off-design conditions in pump which are studied in this paper. The paper outlines a technique for efficiently obtaining the numerical solution of a pump operating in off-design conditions by leveraging the solution obtained under design conditions. This method is referred to as a “sensitivity solution”, wherein small parameter adjustments are made, and simulations are conducted starting from an already converged solution. Test was done for change in impeller speed and it was found that for one percentage change, sensitivity solution was obtained in one-fourth time compared to its baseline simulation. For the flow rate variation, for two percentage change, sensitivity solution is obtained in one-fifth time. Results support use of sensitivity method for solving flows for variations up to ten percent. Variation in output parameter is seen to be higher in case of speed changes compared to the flow rate.