Numerical Simulation about the Impacts of the Secondary Side Flow Distributions on the Flow and Heat Transfer in a Steam Generator

Taken the steam generator of Daya Bay Nuclear Power Plant as the prototype, the "unit pipe" three-dimensional physical model of steam generator is established under the guidance of the similarity principle. Numerical simulation is implemented about the impacts of the secondary inlet flow distributions on the flow and heat transfer in a steam generator based on CFX by adopting flow-solid coupled heat transfer method and thermal phase change model. Compared with a inlet flow distribution ratio of 1:1, when the distribution ratio of the inlet secondary side flow is 4:1, the results show that a long secondary preheating section results, together with a low cross-section void fraction of the hot leg and a high value for the cold leg . The export mass fraction is consistent with the practical operating parameters of Daya Bay Nuclear Power Plant. Due to the fact that fluid velocity in the region of U bend for the secondary side flow is smaller, flow-induced vibration damage in U-bend tubes of the cold leg region is mitigated. Distributions of wall temperature are basically consistent with the experimental results; while tube wall has a low average temperature, especially in the hot leg. The numerical simulation method could provide technical support to accurately determine the flow distribution ratio of the secondary side for different types of steam generator.