The S–CO₂ Brayton cycle has been considered as a promising alternative in coal-fired power plants due to its high efficiency and high compactness. However, the high inlet temperature and low heat transfer coefficient of S–CO₂ in the cooling wall tubes arranged in the furnace could lead to thermal fragile in practical operation. In present study, thermal-hydraulic-structural evaluation on S–CO₂ cooling wall tubes is investigated. Firstly, it is found that the stress distribution is mainly dominated by the circumferential temperature gradient. Secondly, a new criterion, the thermal deviation factor (TDF), is proposed to evaluate the tube thermal stress. It indicates the plastic deformation if exceeding the critical value of TDF = 1, which is more efficient than conventional structural analysis. Thirdly, based on the TDF, two typical methods of inserting twisted tapes and unilaterally arranging dimples inside the tube are proposed to reduce the thermal stress. A novel configuration of elliptic dimple with rounded corners is finally proposed to reduce the local stress concentration efficiently. The results show that the elliptic dimples have the highest comprehensive performance, which is recommended as the heat transfer enhancement structures in S–CO₂ cooling wall tubes.

S-CO ₂布雷顿循环因其高效率和高紧凑性而被认为是燃煤电厂的一种有前途的替代方法。然而，在炉内布置的冷却壁管中，S-CO _{2 的}入口温度高，传热系数低，在实际操作中可能导致热脆性。在本研究中，研究了 S-CO ₂冷却壁管的热工水力结构评估。首先，发现应力分布主要受圆周温度梯度支配。其次，提出了一种新的标准，即热偏差因子（TDF）来评估管子的热应力。超过临界值表示塑性变形TDF  = 1，这比传统的结构分析更有效。第三，在TDF的基础上，提出了两种典型的在管内插入双绞带和单边布置凹坑的方法来降低热应力。最后提出了一种带圆角的椭圆形凹坑的新配置，以有效地减少局部应力集中。结果表明，椭圆形凹坑综合性能最高，推荐作为S-CO ₂冷却壁管的传热强化结构。