Abstract Within the framework of the Work Package DIV 1 - “Divertor Cassette Design and Integration” of the EUROfusion action, a research campaign has been jointly carried out by University of Palermo and ENEA to investigate the thermal-hydraulic behaviour of the DEMO divertor cassette cooling system, focussing the attention on the 2018 configuration of the Plasma Facing Components (PFCs) circuit consistent with the DEMO baseline 2017. The research campaign has been carried out following a theoretical-computational approach based on the finite volume method and adopting the commercial Computational Fluid-Dynamic (CFD) code ANSYS CFX. A steady-state CFD analysis has been carried out for the PFCs cooling circuit under nominal conditions and its thermal-hydraulic performances have been assessed in terms of coolant total pressure drop, flow velocity and Critical Heat Flux (CHF) margin distributions among the Plasma Facing Units (PFUs) channels, to check whether they comply with the corresponding limits. Results obtained have clearly predicted a total pressure drop of ≈1.7 MPa, slightly higher than the prescribed limit of 1.4 MPa, as well as a sufficient margin against CHF onset, higher than 1.4 except for three IVT PFU channels where a minimum value of 1.39 is predicted. Moreover, a parametric study has been performed in order to assess the operating map of the cooling circuit in the phase-space of coolant inlet temperature, pressure and mass flow rate, to be intended as that domain where the circuit thermal-hydraulic performances let it stay within the prescribed requirements. Models, loads and boundary conditions assumed for the analyses are herewith reported and critically discussed, together with the main results obtained.

中文翻译：

---

关于 DEMO Divertor Plasma Facing Components 冷却回路的热工水力运行图的数值评估

摘要 在 EUROfusion 行动的工作包 DIV 1 -“导流器盒设计和集成”的框架内，巴勒莫大学和 ENEA 联合开展了一项研究活动，以调查 DEMO 导流器盒冷却的热工水力行为系统，重点关注与 2017 年 DEMO 基线一致的等离子面向组件 (PFC) 电路的 2018 年配置。该研究活动是按照基于有限体积方法的理论计算方法进行的，并采用商业计算流体-动态 (CFD) 代码 ANSYS CFX。在标称条件下对 PFCs 冷却回路进行了稳态 CFD 分析，并根据冷却剂总压降对其热工水力性能进行了评估，等离子单元 (PFU) 通道之间的流速和临界热通量 (CHF) 裕度分布，以检查它们是否符合相应的限制。获得的结果清楚地预测总压降约为 1.7 MPa，略高于规定的 1.4 MPa 限制，并且有足够的防止 CHF 发作的裕度，高于 1.4，但三个 IVT PFU 通道除外，其中最小值为 1.39预料到的。此外，还进行了参数研究，以评估冷却液入口温度、压力和质量流量相空间中冷却回路的运行图，旨在作为回路热工水力性能允许的域保持在规定的要求内。楷模，