有效导热系数模型在核热推进反应堆的应用  

Effective thermal conductivity model applied in pellet bed reactors for nuclear thermal propulsion

作　　者：游尔胜 李依依 王甜蜜 幸奠川[1] 吉宇[2] 徐建军[1] YOU Ersheng;LI Yiyi;WANG Tianmi;XING Dianchuan;JI Yu;XU Jianjun(CNNC Key Laboratory of Nuclear Reactor Thermal Hydraulics Technology,Nuclear Power Institute of China(NPIC),Chengdu 610213,China;Institute of Nuclear and New Energy Technology,Tsinghua University,Beijing 100084,China)

机构地区：[1]中国核动力研究设计院中核核反应堆热工水力技术重点实验室,四川成都610213 [2]清华大学核能与新能源技术研究院,北京100084

出　　处：《火箭推进》2024年第4期94-102,共9页Journal of Rocket Propulsion

基　　金：国家自然科学基金联合基金(U1967203)。

摘　　要：核热推进反应堆一般选用氢气做工质,通过堆芯燃料颗粒加热到高温,以实现较高的发动机推力和比冲。基于美国核热推进火箭发动机的典型堆芯设计方案,在高温气冷堆球床有效导热系数模型的基础上,对更小直径的燃料颗粒与更高温度的氢气工质组成的颗粒床混合介质进行了初步计算,获得了燃料种类、颗粒直径、孔隙率等关键参数对堆芯导热能力的影响规律。同时,考虑到燃料颗粒采用多种材料复合而成的包覆型结构,采用均匀化方法对不同材料的基础热物性进行了等效计算,从而为有效导热系数模型提供固体域平均导热参数。从计算结果来看,颗粒直径和孔隙率对有效导热系数的影响更大,特别是高温条件下辐射换热作用占主导,使得材料自身导热系数的贡献很小。Nuclear thermal propulsion(NTP)is a new-type nuclear reactor application which chooses hydrogen gas as the working medium,heated by fuel pellets in the reactor core to extremely high temperature,so as to achieve huge thrust and high specific impulse.Based on the typical design of reactor core in American NTP rocket engine programs,the effective thermal conductivity model of high temperature gas-cooled reactors was used and preliminary applied,for the analysis of the pellet bed mixed with smaller fuel particles and higher temperature hydrogen gas.The influences of fuel type,pellet diameter and pellet bed porosity on the thermal conductivity of the reactor core were also obtained in this paper.Meanwhile,considering that the fuel pellet was usually coated by multi-layers with different materials,the homogenization method was used for equivalent calculation in thermal properties of these materials,aimed to provide the average thermal conductivity parameters of solid domain for the effective thermal conductivity model.According to the calculation results,the pellet diameter and pellet bed porosity have a greater impact on the effective thermal conductivity,relative to the components thermal conductivity,especially under high temperature conditions that the radiation heat transfer is dominant.This paper has important significance for the development of NTP rocket engines with the capacity of further design and thermal hydraulics analysis of pellet bed reactors.

关 键 词：有效导热系数 模型应用 颗粒床反应堆 核热推进 

分 类 号：TL99[核科学技术—核技术及应用]