The interaction between fluid and a down-pumping pitched blade turbine fixed with a flexible shaft in the stirred vessel

as a typical fluid structure interaction phenomenon

was simulated by coupling the Computational Fluid Dynamics and Computational Structural Dynamics. Based on the verification of the simulated impeller torque and dimensionless shaft bending moment with experimental result

the dimensionless shaft bending moment and various loads acting on impeller (including lateral force

axial force and bending moment) were discussed in detail. By separating and extracting the fluid and structural components from those loads

the results show that the shaft bending moment mainly results from the lateral force on impeller although the axial force on impeller is much larger. The impeller mass imbalance increases the shaft bending moment and the lateral force on impeller

but has little influence on the axial force and bending moment acting on impeller. The dominant frequencies of impeller forces are macro-frequency

speed frequency and blade passing frequency

and are associated with the impeller mass imbalance.