Improving the efficiency of regenerative blower impellers

Results of a study concerning the influence of impeller blade shape on increasing the efficiency of regenerative blowers are presented. Three impellers designed with different angles for the blades at inlet and outlet sections are considered: straight blades impeller (β
₁
= β
₂
= 90
⁰
), forward twisted blades and backward twisted blades (β
₁
= 90
⁰
; β
₂
= 105
⁰
). Experimental research reported highest values for the pressure coefficients (Ψ) and flow coefficients (φ) for the impeller with forward twisted blades. In this case the values for the blower efficiency was 1.2-2% higher then those reported by the other two impellers and same casing. As the outlet blade angle is increasing and the blades are more twisted forward better performances are available. The solution of twisted blade is more effective then simply inclined blade when comparing the efficiency values at similar design data.