Peak Temperature Prediction Method Based on A Theoretical Model of Equivalent Thermal Conductivity for Fully Ceramic Microencapsulated Fuel
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摘要: 为了满足工程上对全陶瓷微封装(FCM)燃料峰值温度快速预测的需求,可以将燃料的等效导热系数代入至简化的均质导热模型中进行燃料峰值温度的反计算。本文基于前期提出的多环导热模型,从基本导热方程出发,以燃料峰值温度为守恒量,将多环模型进一步等效为均质模型,推导了FCM燃料等效导热系数计算理论模型,并将该模型与常规等效导热系数理论模型进行对比。结果表明:本文构建的理论模型可以在多环模型的基础上结合均质模型从而有效地实现对燃料峰值温度的预测。该方法所预测的峰值温度值与实际值偏差基本在3%以内,因而可适用于对含内热源FCM燃料元件峰值温度的预测。本文建立的基于等效导热系数理论模型的预测方法可实现对FCM燃料峰值温度的快速预测。
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关键词:
- 全陶瓷微封装(FCM)燃料 /
- 三结构同向性型(TRISO)燃料 /
- 等效导热系数 /
- 多环导热模型 /
- 峰值温度预测
Abstract: In order to satisfy the engineering need for rapid prediction of peak temperatures of Fully Ceramic Microencapsulated (FCM) fuels, inverse calculations of peak fuel temperatures could be performed by substituting the equivalent thermal conductivity of the fuel into a simplified homogeneous thermal conductivity model. In this paper, based on the multi-annulus model developed in previous study, a theoretical model for calculating the equivalent thermal conductivity of FCM fuel is derived by starting from the basic thermal conductivity equation and taking the peak fuel temperature as a conserved quantity, and the multi-annulus model is further equivalent to a homogeneous model. Then the derived model is compared with some conventional equivalent thermal conductivity theoretical models. The results show that the developed theoretical model could be combined with the homogeneous model to effectively achieve the prediction of peak fuel temperatures. The developed theoretical method is suitable for predicting the peak temperature of FCM fuel elements with internal heat sources, because the deviation between the predicted peak temperature and the actual value is basically within 3%. The developed theoretical model prediction method based on equivalent thermal conductivity could realize the rapid prediction of the peak temperature of FCM fuel. -
表 1 TRISO燃料颗粒几何和物性参数
Table 1. Parameters of TRISO Fuel Particle
表 2 FCM燃料元件几何和物性参数
Table 2. Parameters of FCM Fuel Element
燃料元件结构 外半径/µm 高度/µm 导热系数/(W·m−1·K−1) 燃料芯块 4150 13500 气隙 4235 13500 0.28 燃料包壳 4800 13500 16.6 表 3 不同工况下的线功率
Table 3. Linear Power under Different Conditions
工况 1 2 3 4 5 6 线功率/(W·cm−1) 165 215 265 315 365 415 -
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