Effect of Cracked Blade Distribution on Strength of Centrifugal Impeller

In this paper, the finite element analysis is made to the structure of the impeller, a finite element model of a impeller with cracks was established. This paper presents results of the stress analysis of the compressor blade subjected to centrifugal force and aerodynamic equilibrium pressure. A nonlinear finite element method was utilized to determine the stress state of the blades. In this analysis, the numerical models without defects and also with cracks were defined. The simulation results showed that high stresses occurred in the areas where the cracks initiated under both centrifugal force and aerodynamic equilibrium pressure. The distribution of two cracked blades can greatly influence the stress level of the impeller; when two cracked blades locate in the adjacent positions，the increasing value of stress is minimum. When the two cracked blades separated by 150°, the increasing value of stress is maximum. It provides a basis for strength calculation of the impeller.