Effects of rotating speed on the unsteady pressure pulsation of reactor coolant pumps with steam-generator simulator

Non-uniform suction flow is generated at the inlet of the reactor coolant pump due to the complex geometry of the steam-generator simulator. From our previous work, the non-uniform inflow has a great effect on the flow structures in the pump. The unsteady pressure pulsation characteristics in a reactor coolant pump with steam-generator simulator are investigated in various flow rates and various rotational speeds. Pressure pulsation signals measured from the sensors on the pump casing and outlet pipe are analysed by FFT (Fast Fourier Transform) and RMS (Root Mean Square) method. Pressure pulsation characteristics, both discrete peaks and RMS values, are easily affected by different operational conditions and measuring positions. Pressure amplitudes at fRPF increases with rotation speed increasing in different flow rates, but pressure amplitudes at fR and fSPF fluctuate slightly with the rotation speed increasing. Meanwhile, the effect of rotational speed on pressure pulsation are analysed. It is found that pressure amplitudes of RMS value and fRPF increase with rotating speed increasing. This means that low rotating speed will reduce the pump vibration, so adjusting rotating speed is an appropriate method to stable operation of the pump. Finally, the present work will provide a different view on the pressure pulsations in the pump with non-uniform inflow in different rotation speeds. This research is helpful to provide a good reference for non-uniform inflow study of the pump, and it is helpful to the vibration analysis and fault diagnosis of the pump.