Capacity Enhancement of a Double Suction Centrifugal Pump by Numerical Simulation and Optimization Design Method
摘要
In practice, there is sometimes a need to increase the flow rate according to demand in permanent water supply systems. In this study, by retrofitting the impeller of the double suction centrifugal pump, the operating flow rate of the pump was increased by 32.7% over the previous one. Using a two-dimensional design method, an impeller was designed to satisfy the new flow rate requirement, and the response surface optimization was performed to maximize the hydraulic efficiency while maintaining the head. The optimization was carried out through the process of experimental planning by central composite design, performance prediction by CFD simulation, response surface construction by non-parametric regression, and search of optimal points by genetic algorithms. The combination of BladeEditor, ICEM CFD, TurboGrid, CFX, and DesignXplorer in ANSYS facilitated the parameterization and optimization of the impeller. By optimization, the pump efficiency at the design point was 3.2% higher than the initial design value. The performance of the pump after impeller retrofitting was validated by numerical simulation and experiments. A method is presented to estimate the actual pump performance from the simulation results obtained with a mesh model without reflecting the gap between the impeller and the casing. The numerical simulation results are verified by comparison with the experimental results. By retrofitting the impeller, the operating flow rate increased from 3300 to 4380 m3/h, and the head increased from 50.4 to 57.2 m. Our results show that increasing the pump flow rate by 30% from the original one is feasible by retrofitting only the impeller. The method used in this paper can help to improve performance at low cost by modifying only the impeller in other pumps with extra motor power.