NUCLEAR TECHNIQUES, Volume. 48, Issue 7, 070003(2025)
Comprehensive analysis of CFD application in thermal-hydraulic of Generation IV reactors
Figures & Tables(11)
Fig. 1. Thermal hydraulic characteristics and concerning aspects in the research of the Generation Ⅳ reactors
Fig. 2. Study on flow characteristics of local key components in SFR (color online)(a) CFD calculation of full core 81 assemblies with 61 wire - wrapped fuel rod bundles[8], (b) Thermal hydraulic simulation of the Intermediate Heat Exchanger
Fig. 3. Illustration of thermal-hydraulic CFD analysis of large-flow-region in SFR systems (color online)
Fig. 4. Schematic diagram of the molten salt reactor (a), the streamline of its lower chambers (b), and the temperature distribution of the molten salt channels in the reactor core (c)[43] (color online)
Fig. 6. Prismatic HTGR (a) Diagram of partial structure model and meshing, (b) Temperature even and RSN distribution contour of the core section along the axial direction of fuel[68] (color online)
Fig. 7. Diagram of distribution of velocity and temperature in the unit pebble bed[75] (color online)
Fig. 8. Challenges faced by CFD applications and main solutions approaches
Table 1. The main models used for the closed study of turbulent heat flux
View tableView in ArticleTable 1. The main models used for the closed study of turbulent heat flux
类别Type 名称Name 特点Characteristics 湍流普朗特数模型
Turbulence Prandtl number model
Prt常数模型
Constant Prtmodel
将Prt作为固定值封闭THF模型；部分学者通过改变Prt值，改善了强迫对流换热计算结果
The THF model is closed with Prt as a fixed value in this model. Some scholars have improved the calculation results of forced convective heat transfer by changing the Prt value.
全局模型
Global model
增加对全局流动状态的考虑，依据液态金属的实验数据拟合经验关系式，但该模型的Prt在空间上的分布仍是定值The consideration of the global flow state has been added in this model, with the empirical relationship being fitted based on the experimental data of liquid metal. However, the spatial distribution of the Prt in it is still constant. 局部模型
Local model
引入湍流佩克莱特数Pet，提出了Prt随空间非线性分布的关系式，解决了全局模型Prt在空间上的分布问题，但其几何条件和边界条件相当局限，其可靠性和适用性有待验证
The turbulent Péclet number Pet is introduced through this model, and the relationship of the nonlinear spatial distribution of Prt has been proposed, which has solved the spatial-distribution problem of the global-model Prt. However, the geometric and boundary conditions of this model are rather limited, thus its reliability and applicability remain to be verified.
代数热通量模型Algebraic heat flux model 广义梯度扩散假设Generalized gradient diffusion hypothesis 考虑雷诺应力对THF的影响，提高了在浮力驱动流中对各向异性湍流热扩散的预测精度
In this model, the influence of Reynolds stress on THF is considered, thus improving its prediction accuracy of anisotropic turbulent thermal diffusion for the buoyance-driven flow.
隐式代数热通量模型
Implicit algebraic heat flux model
依据弱平衡假设，简化得到的THF模型；单套系数无法满足所有情形，可以通过改变模型系数使其适应不同的计算工况This THF model is a simplification based on the weak equilibrium assumption. It cannot fulfil all situations with a single set of coefficients. However, it is plausible to adjust the model coefficients to adapt it to different calculation conditions. 显式代数热通量模型
Explicit algebraic heat flux model
沿用梯度扩散思想，假设THF与平均温度梯度成正比，比例系数为αt，通过αt代数方程间接表示THF，在强迫对流工况下有巨大潜力
This model (AHFM) follows the idea of gradient diffusion, it is still assumed that THF is proportional to the average temperature gradient, with a proportionality coefficient of αt. The THF in this model is represented by the αt algebraic equation indirectly, equipping it with great applicational potential for forced convection conditions.
二阶矩闭合模型Second-moment closed model 二阶矩闭合模型
Second-moment closed model
擅长模拟不均匀、各向异性的湍流传热行为，但其模型过于复杂，在实际工程计算的可行性仍需广泛的验证This model is suitable for simulating the turbulent heat transfer behaviors of non-uniformity and anisotropy, but with it showing excessive complexity, its feasibility in practical engineering calculations still needs to be extensively verified. 机器学习闭合模型
Machine learning closed model
机器学习闭合模型
Machine learning closed model
利用数据驱动方法修改或重构传统模型，增强THF模型处理非线性问题的能力，但模型在训练工况外可能失效，需要通过迁移学习提高泛化能力
Using the data-driven method, the traditional model has been modified or reconstructed in this model, and the ability of the THF model to handle nonlinear problems has been enhanced. However, the model may fail outside the training conditions, leading to its generalization ability requiring improved through transfer learning.
Table 2. Multi-scale code coupling methods
View tableView in ArticleTable 2. Multi-scale code coupling methods
耦合方式
Coupling method
显式耦合
Explicit coupling
半隐式耦合
Half-implicit coupling
隐式耦合
Implicit coupling
数据传递方向
Data transmission
direction
单向
Unidirectional
双向多次交换
Bidirectional with multiple exchanges
联合求解
Joint solution
时间步长限制
Time step restriction
严格受CFL条件约束
Strictly constrained by CFL
condition
部分放宽但仍可能受限
Partially relaxed, but still may be limited
完全不受限
Completely unrestricted
稳定性Stability 易发散Prone to divergence 中等Moderate 强稳定Strong stability 计算成本
Computational cost
低Low 中等Moderate 极高Extremely high 适用场景
Applicable scenarios
参数平缓变化，快速计算
Parameters change smoothly, fast calculation
中等非线性，需反馈控制
Moderate nonlinearity, feedback control is required
强非线性，多物理场强耦合
Strong nonlinearity, multi-physics field strong coupling
实现复杂度
Implementation complexity
简单
Simple
中等
Moderate
需全局迭代框架
Requires a global iterative framework
Table 3. Criteria for technology maturity levels
View tableView in ArticleTable 3. Criteria for technology maturity levels
TRL等级
TRL level
要求
Request
目标
Target
TRL 1 基础原理被提出但尚未进行实验验证
The basic principle has been proposed, yet has not been experimentally verified
基础研究与概念验证
Basic research and proof of concept
TRL 2 技术概念形成且初步实验验证完成
The technical concept is formed and the preliminary experimental verification is completed
TRL 3 关键功能在实验室环境中得到验证
Key features are validated in a lab environment
TRL 4 组件或子系统在实验室环境中集成并验证
Components or subsystems are integrated and validated in a lab environment
技术开发与原型验证
Technology development and prototyping
TRL 5 组件或子系统在模拟环境中验证
Components or subsystems are validated in a simulated environment
TRL 6 系统原型在相关环境中验证
System prototypes are validated in the relevant environment
TRL 7 系统原型在实际环境中验证
System prototypes are validated in a real-world environment
系统集成与商业化
System integration and commercialization
TRL 8 系统完成并通过测试准备商业化
The system is completed and tested, and ready for commercialization
TRL 9 技术成功应用于实际场景且商业化完成
The technology has been successfully applied to practical scenarios and commercialized
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Guangliang CHEN, Wenquan TAO, Dechang CAI, Xinli YIN, Jinchao LI, Gang TAN, Shuqi MENG, Guodong YE, Xiong ZHENG. Comprehensive analysis of CFD application in thermal-hydraulic of Generation IV reactors[J]. NUCLEAR TECHNIQUES, 2025, 48(7): 070003
Paper Information
Category: Special Issue on The First Academic Annual Conference of the Research Reactor and Innovative Reactor Association of Chinese Nuclear Society and Advanced Nuclear Power System Reactor Engineering
Received: Apr. 23, 2025
Accepted: --
Published Online: Sep. 15, 2025
The Author Email: Wenquan TAO (TAOWenquan)
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