The fluid field pressure distribution was obtained using the fluid-solid interaction technology with the combination of computational fluid dynamics(CFD)flow analysis and finite element method(FEM)structure analysis. The aerodynamic loads were exerted on the solid blade surfaces to analyze strain and stress. Then the centrifugal force was added as another load to the blade and the deformation of the centrifugal blade under working condition was achieved. The running blade profile was gained by calculating the deformation magnitude of the solid grid nodes

and the fluid field in the deformed blade passage was analyzed. To evaluate the influence of deformation on the impeller performance with tip clearance variation

the calculations of three kinds of tip clearance distributions were conducted. The results show that the deformation under the aerodynamic load is only about 1%-3% of that under the total load and the largest deformation occurs at the blade inducer tip. The tip clearance decreases from the inlet to the outlet of the blade because the deformed blade root and tip are close to the casing. When the tip clearance of the undeformed blade is 0.5mm

the tip clearance at the deformed blade outlet can decrease by up to 50%. In addition

the isoentropic efficiency of the centrifugal impeller at low flow rate decreases by 0.9%-1.8%because of the variations of the tip clearance and the blade profile.