Improvement of efficiency by design optimization of a centrifugal pump impeller

Shape optimization of centrifugal impeller blades has been performed through numerical analysis and implementation of multiple surrogate based optimization methodology. Design variables which are used to define blade angles at leading and trailing edges were introduced to increase the hydraulic efficiency of the impeller. The efficiency was selected as an object function and the optimization was performed using a surrogate base optimization methods. A three-dimensional simulation using Reynolds-averaged Navier Stokes equations for the performance analysis was carried out after designing the geometries of the impellers at the design points selected from the design space which was defined by the lower and upper limits of the variables. Throughout the shape optimization, the hydraulic efficiency was increased by decreasing losses near the blade surfaces and impeller passage. Among different surrogates, a weighted average model produced better results. The application of the multiple surrogate methods not only improved quality of single objective optimization but also gives the feedback of the fidelity of the optimization models.