System Matched 3D Radial Impeller Design With Variable Inlet Angle Distributions

In vacuum cleaners radial impellers with high rotational speed are very often used. A high rotational speed is connected with a best efficiency point of the radial impeller at a high flow rate. This is contrary to the working point of the whole system. Thus there is need for a radial impeller designs having a high efficiency at low flow rates under the restriction of a high rotational speed. One important parameter connected to the hydraulic efficiency characteristics of the radial impeller is the blade inflow angle β₁. In order to shift the best efficiency point towards lower flow rates radial impellers with double curved blades and a linear β₁ distribution were designed and CFD simulations were done in order to investigate the effect of this approach. A linear variation of the inflow angle β₁ enables the designer to shift the efficiency characteristics of the impeller towards lower flow rates with a gain in hydraulic efficiency and pressure increase.