In order to determine the optimal structural parameters of a plastic centrifugal pump in the framework of an orthogonal-experiment approach, a numerical study of the related flow field has been performed using CFX. The thickness S, outlet angle β2, inlet angle β1, wrap angle, and inlet diameter D1 of the splitter blades have been considered as the variable factors, using the shaft power and efficiency of the pump as evaluation indices. Through a parametric analysis, the relative importance of the influence of each structural parameter on each evaluation index has been obtained, leading to the following combinations: β1 19°, β2 35°, S 2 mm, wrap angle 154°, and D1 85 mm (corresponding to the maximum efficiency of 75.48%); β1 19°, β2 20°, S 6 mm, wrap angle 158°, and D1 81 mm (corresponding to the minimum shaft power of 75.48%). Moreover, the grey correlation method has been applied to re-optimize the shaft power and efficiency of the pump, leading to the following optimal combination: β1 19°, β2 15°, S 4 mm, D1 81 mm, and wrap angle 152°(corresponding to the maximum efficiency of 71.81% and minimum shaft power of 2.187 kW).

The structural design parameters of a plastic centrifugal pump were calculated and modeled, and flow field simulation analysis of the model was performed using CFD, in the framework of an orthogonal design method (or experiment). The inlet mounting angle β1, outlet mounting angle β2, wrap angle ϕ, and impeller inlet diameter D1 of the pump impeller were the four factors assumed for the application of the orthogonal experiment, using the efficiency and Net Positive Suction Head (NPSH) as evaluation indices. Moreover, taking the maximum efficiency and minimum NPSH of the plastic centrifugal pump as the evaluation factors, the parameters of the pump impeller were re-optimized through the Taguchi algorithm (leading to the following optimal combination: inlet diameter 35 mm, inlet angle 26°, outlet angle 27°, and wrap angle 110°). The minimum NPSH and the maximum efficiency have been found to be 0.957% and 61.5%, respectively.