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| Impeller pressure pulsation and internal flow law of reactor coolant pump during idling process based on wavelet transform |
| LIU Anlin1, YE Daoxing1,2,3*, LUO Yimin1, CHEN Junlin1, YU Bo1, LAI Xide1,WU Jinchen1, ZHAI Fengli1 |
| 1. School of Energy and Power Engineering, Xihua University, Chengdu, Sichuan 610039, China; 2. Key Laboratory of Fluid and Power Machinery, Ministry of Education, Chengdu, Sichuan 610039, China; 3. Sichuan Key Laboratory of Fluid Machinery and Engineering, Chengdu, Sichuan 610039, China |
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Abstract In order to study the flow law in the reactor coolant pump during idling process, the numerical simulation method was used to calculate the internal flow field of the reactor coolant pump, and the time-frequency characteristics of pressure pulsation in the impeller channel with different idling flow time(TQi)were obtained. The pressure pulsation of the impeller was analyzed by wavelet transform, and the vortex identification of the flow components under different working conditions was carried out by using the second generation vortex identification method Q criterion. The results show that the maximum change of pressure fluctuation coefficient occurs in the middle of the guide vane at the initial stage of idling process, then the maximum change rate occurs at the dynamic and static interface between the impeller and the guide vane, and finally the pressure fluctuation tends to be stable. With the decrease of impeller speed and flow rate, the work area of the guide vane moves to the vicinity of the outlet. Due to the special structure, the tongue part is greatly impacted, and there is backflow nearby, mean while and there is a sign of diffusion to the middle of the flow channel. The pressure pulsation tends to be stable, and the main frequency shifts to the low frequency. The pressure pulsation regularity in the flow channel of each component is gradually destroyed, and the change trend of the guide vane flow channel is relatively gentle. Some of the strong vortex regions in the channel indicates of separation and shedding, and the number gradually decreases. The vortex core in the pumping chamber is mainly concentrated on the left side, which is related to the rotating direction of the impeller. The research can provide some support for the optimization design of the idling characteristics of the reactor coolant pump.
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Received: 22 December 2021
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