Investigation of dynamic stress of rotor in residual heat removal pumps based on fluid-structure interaction

Vibration and dynamic stress caused by the interaction between the fluid and the structure can affect the reliability of pumps. This study presents an investigation of internal flow field and the structure response of residual heat removal pump using a combined calculation for turbulent flow, and the structure response of rotor was first defined using a two-way coupling method. For the calculation, the flow field is based on the shear stress transport k-v turbulence model and the structure response is determined using an elastic structural dynamic equation. The results show that the domain frequencies of pressure fluctuations of monitors on the outlet of impeller are the integer multiples of rotating shaft frequency (f(n)) and the amplitude of the relatively large pressure fluctuation peak is the lowest under the design flow rate operating condition. Meanwhile, the time-average radial force value at the design flow rate condition is the smallest and the hydraulic force magnitude at the maximum operating flow rate condition is the largest, and phase difference can be clearly seen among the results obtained under different flow rates. Furthermore, the relatively large stress of rotor for all operating conditions is the biggest at shaft shoulder where the bearing is installed, and it increases with flow rate.