Optimization design of high-speed impeller for high-performance and low-noise cordless vacuum cleaner

In this study, the flow and noise performances of high-speed fan-motor unit for cordless vacuum cleaner is improved by equipping splitter blades on the impeller which drive the suction air through flow passage of the cordless vacuum cleaner. First of all, in order to investigate the flow field through the fan-motor unit, especially impeller, the unsteady incompressible RANS equations are solved. Based on flow field results, the FW-H integral equation is used to predict radiated flow noise from the impeller. Predicted results are compared to the measured ones to validate the numerical method used. It is found from the predicted flow field that the strong vortex is formed around the mid-chord region of the main blades where the blade curvature change rapidly. As the vortex structure adversely affects both flow and noise performances, supplementary splitter blades is added to the existing impeller to suppress the identified vortex. The response surface method using two factors is employed to determine the optimum location and length of splitter for maximum flow rate and/or minimum radiated noise. The finally selected design shows more flow rate and lower noise than the existing one