Abstract:

Based on the actual operating process of the steam generator in Daya Bay Nuclear Power Plant,a transient simulation of load down from 100% to 50% operating condition was carried out by utilizing the CFD technologies to reveal the dynamic variation rule of steam generator heat-transfer characteristics in the load down process.The simulation results show that fluid thermal parameters of the primary and secondary sides decrease over time in the load down process.With the decrease of heat transfer intensity,the perturbation impact of tube support plates(TSPs)on steam quality,fluid velocity,and surface heat transfer coefficient in the secondary side decrease gradually.Corresponding to the operating condition of 100%,70% and 50%,the fluid temperature of primary outlet is 297.2,295.6 and 294.8℃ and the steam quality at the outlet of secondary outlet is 24.5%,16.7% and 12.1%,respectively,which are in consistent with actual operating parameters of steam generator in Daya Bay Nuclear Power Plant.These results can provide theoretical support to the safe operation and optimization design of steam generator.

Key words: steam generator, thermal-hydraulic characteristics, transient simulation, multiphase flow, model reduction, heat transfer

摘要：

基于大亚湾核电站蒸汽发生器实际运行过程,采用CFD技术,对其100%~50%工况的降负荷过程进行瞬态模拟,以揭示蒸汽发生器流动传热特性在降负荷过程中的动态变化规律。计算结果表明,降负荷过程中,一、二次侧流体热工参数均随时间降低,而且随着换热强度下降,支撑板(TSPs)对二次侧含汽率、流速及表面换热系数的扰动作用也逐渐减弱。对应于100%、70%及50%三种工况,一次侧流体出口温度分别为297.2、295.6和294.8℃,二次侧出口流体平均质量含汽率分别为24.5%、16.7%和12.1%,模拟结果均与大亚湾核电站运行过程中的实际值相符。研究结果为蒸汽发生器的安全运行及优化设计提供了理论参考。

关键词: 蒸汽发生器, 热工水力特性, 瞬态模拟, 多相流, 模型简化, 传热