LAUSR

Recent failures of pulverizing wheels in fan mills of a steam turbine power plant show that the dovetail-groove area of the main components (the front disk and the back disk) is vulnerable. With the purpose of improving strength and optimizing design, this work analyzes different material sets used in components and compares various supporting strategies of the critical section to decrease maximum stress in the zone of vulnerability (ZoV). Finite element method is applied in modeling the pulverizing wheel, and nonlinear material property is formed based on bilinear kinematic hardening rule. Typical loading conditions in operation are applied to compare the nonlinear stress and strain distributions and the maximum. The results show that using an alternative material introduces a series of variations of the stress and strain in the assembly. Also, optimizing the supporting strategy can significantly decrease the maximum stress and strain, and the variation of the ZoV should also be considered to compare the enhancement of strength of the whole structure.