Design Optimization for the Hydraulic Efficiency Improvement of a Mixed-Flow Pump Diffuser

In this paper, design optimization for mixed-flow pump diffusers was carried out using a commercial computational fluid dynamics (CFD) code and design-of-experiments (DOE). The design variables of meridional plane and vane plane development were defined for the diffuser design. The blade shape of the diffuser was designed using the traditional method, in which the inlet and exit angles are connected smoothly. First, the design optimization of the defined design variables for vane plane development was achieved. Next, design optimization of the defined design variables for the meridional plane was performed. The objective functions were defined as the total head and total efficiency of the diffusers. The importance of the geometric design variables was analyzed using 2^k factorial designs, and the design optimization of the geometric variables was determined using the response surface method (RSM). The numerical results for reference and optimum models in this work were compared and discussed.