Comparative strength analysis of two popular options of the radial centrifugal fan impeller design used in horizontal conveyor dryer for fine-grained raw materials is presented. Three types of materials for impeller manufacturing-ASTM A36 steel, Hardox 450 steel and aluminium alloy 6061-T6 are considered. The finite element method (FEM) has been used to investigate stresses and deformations of the impeller within the operational speed range. Analysis shows that the better design is the impeller made of Hardox 450 steel with a central disk. Although the maximum stress is slightly higher in the blades slot for central disk fitting for this design option, it has greatly reduced stresses in contact edges with two other disks (by 22-38%) and blades bending deformation (by 51%). For this design, the maximum operational rotation speed is 1135 min-1 according to the yield strength with a 15% safety factor, while for basic design, it is 1225 min-1. The rational choice of material depends on maximum value of the yield stress to density ratio as well as taking into account the operating conditions and required fan performance. Recommendations for manufacturing the centrifugal fan impeller related to chosen material are given.
Keywords: FEM; centrifugal fan; horizontal conveyor dryer; impeller; raw materials.