棒束通道温度场可视化实验研究

基于激光诱导荧光技术，对带定位格架棒束通道的温度场进行了可视化实验研究。采用折射率匹配技术，搭建可视化实验系统，提出适用于棒束通道温度场点对点标定的关系式，利用此关系式对定位格架下游温度场进行了重构。实验结果显示，采用激光诱导荧光技术可获得定位格架下游全场温度分布。分析了不同加热形式、流量和热流密度对温度分布的影响，并采用轴向流体温差和温度分布不均匀性定量评价了定位格架下游的搅混能力。在定位格架下游0～4D_h范围内，搅混性能逐渐增大，在4D_h后会随高度的增加逐渐减小。结果表明，激光诱导荧光技术可适用于棒束通道温度场的非介入式、全场测量，有助于对相应程序的验证和定位格架搅混性能的评价。

Visual Experimental Investigation of Temperature Field inside Rod Bundle

Laser induced fluorescence (LIF) technique was applied to investigate the temperature distribution in rod bundles with spacer grid. A visual experiment facility was designed using matching index of refraction (MIR) approach. The point-to-point calibration relations of temperature and light intensity applied to rod bundle were presented. Accordingly, temperature field was reconstructed with the calibration relations. The results show that temperature field of downstream of spacer grid can be obtained using LIF technique. The influences of different heating forms, flow rate and heat flux on temperature distribution were analyzed. Meanwhile, temperature difference on the same axial height and temperature non-uniformity were adopted to evaluate the mixing performance in rod bundle. The mixing performance increases gradually on 0-4D_h downstream of spacer grid, and then decreases with the height. It is concluded that LIF technique is applicable to non-intrusive and full-field measurement in rod bundles, and it can be used as good provider for data base to validate CFD codes and evaluate the spacer grid performance.