Investigation on optimization of centrifugal fan impeller based on the blade angle distribution law

Centrifugal fans are widely used in various industries. When the efficiency of the centrifugal fan is low, it is often desired to improve its efficiency by replacing the impeller and keeping other components unchanged. The blade angle distribution on the blade streamline can produce different shape blades, which will affect the efficiency of the impeller. However, the blade angle distribution law of the centrifugal fan with good performance is still unclear. In order to improve the performance of centrifugal fans by adjusting the blade angle distribution law, the four different blade angle distribution optimization strategies are designed, the best performance centrifugal fan is obtained through comparative analysis. The investigation shows that compared with the original fan, the efficiency of schemes 1–2 and 4–3 is increased by more than 5%. The pressure distributions on the blade surface are more uniform for schemes 3–6 and 4–3. For schemes 1–2 and 4–3, the number and area of low-pressure zones between the inlet blades are reduced, and the vortices and secondary flows between blades are reduced. Therefore, the impeller performs better under all flow rate operation conditions. The investigation of the external characteristic experimental test of the selected schemes reveals, that the efficiency of schemes 1–2 and 4–3 is 5%–10% higher than the original fan. Scheme 4–3 has a wider high-efficiency area, better overall efficiency, and lower power than scheme 1–2. Scheme 4–3 can meet the pressure rise requirements of the fan, and is an optimal fan optimization scheme with the best fan performance. In this paper, the effect of blade angle distribution on centrifugal fan is studied, and the efficiency of centrifugal fan is improved significantly. The achievements provide scientific guidance for performance optimization of centrifugal fan.