支撑板对蒸汽发生器流动与传热特性的影响

根据相似模化理论,建立了耦合四叶梅花形支撑板的蒸汽发生器单元管三维物理模型,采用流-固传热方法和热力学相变模型,并基于二回路流体进口质量流量按4∶1分配给热、冷端的边界条件进行了支撑板对蒸汽发生器流动与传热特性的影响的数值研究.模拟结果表明:二回路热、冷端侧沸腾规律分布均匀,计算得到的出口含汽率与大亚湾核电站蒸汽发生器实际运行参数相符;支撑板流通截面的缩减,促使二回路侧流体流速、表面传热系数及含汽率在支撑板区域急剧升高又快速降低,同时二回路流体在支撑板上部出现回流现象,增加了支撑板区域杂质沉积及应力腐蚀的可能.该数值模拟方法可为蒸汽发生器支撑板结构优化设计提供技术支持.

Impacts of Tube Support Plate on Flow and Heat Transfer Characteristics of Steam Generator

Based on the similarity principle, a three-dimensional “unit pipe” physical model of a steam generator coupled quatrefoil tube support plate was established. A numerical study of the impacts of tube support plate on steam generator flow and heat transfer characteristics was performed by using the fluid solid coupled methodology and thermal phase change model based on boundary conditions where the secondary side fluid run into the hot leg and cold leg by a distribution ratio of 4∶1. Simulation results show that balanced boiling distributions in the hot leg and cold leg are obtained and the calculated steam quality of the outlet agrees well with the operating parameter of the steam generator at the Daya Bay Nuclear Power Plant. Due to the smaller area of the flow cross section of the tube support plate, the secondary fluid velocity, surface heat transfer coefficient and steam quality sharply increases and then decreases in the support regions, respectively. The recirculation behavior appears at the top of the support plate, which increases the possibility of deposit of particles and tube corrosion. This numerical simulation methodology can provide technical support for the optimization of the structural design of steam generator tube support plate.