基于热-流-固耦合的燃料元件性能分析方法研究

Research on Analysis Method for Performance of Fuel Element Based on Thermal-Fluid-Solid Coupling

中空棱柱形燃料元件形式和运行工况特殊,没有现成的燃料性能分析软件能够满足计算要求,需要建立新的分析方法。本研究基于COMSOL软件二次开发,采用颗粒增强复合材料的等效物性模型和共轭传热技术实现中空六棱柱形燃料的三维热-流-固耦合计算,通过与美国通用电气公司数据的对比证明了该分析方法的有效性。采用该方法计算了多种燃料元件尺寸和不同轴向功率分布下的热应力和温度,结果表明侧棱处温度最高而内壁面壁厚最薄处热应力最大,壁厚越薄、长度越长,燃料元件的最大热应力和温度越小,展平入口段的轴向功率分布也能够略微降低最大热应力和温度。以上分析方法可以用于新型中空棱柱形燃料元件的优化设计。

The existed fuel performance analysis tools are not applicable to the hollow prism fuel with special structure and operation conditions,so a new method is needed to assist the fuel design and evaluation.In this paper,a 3D fluid-thermal-solid coupling analysis method was established based on the COMSOL software by conjugate heat transfer technology and the equivalent material property models for particle reinforced composites,and had been verified with the General Electric data.Temperature and thermal stress of fuel elements in different sizes and axial power distributions were calculated with this method.The results show that maximum temperature exists at the side edge of prism,and maximum thermal stress exists at the thinnest inner wall.The thinner and longer fuel has the smaller maximum thermal stress and temperature.Flatting the axial power distribution in the entrance region can decrease the maximum thermal stress and temperature slightly.This analysis method can be used to optimize the design of the hollow prism fuel element.