**4. Conclusions**

The thermal and hydraulic performance of sCO2 in zigzag channels of different pitch lengths (3 mm, 4.5 mm, 6 mm, 7.75 mm), bending angles (100◦, 115◦, 140◦, straight), and hydraulic diameters (1.17 mm, 2 mm, 4 mm) are studied comparatively with the boundary condition covering the pseudocritical point using the CFD method. In this numerical method, the SST k–ω is adopted as the turbulence model and shows the quantitative prediction of the experiments' heat transfer data. The following conclusions were obtained:


**Author Contributions:** Conceptualization, Y.T. and Y.Z.; methodology, Y.T.; software, Y.T.; validation, Y.T. and Y.Z.; formal analysis, Y.T.; investigation, Y.T.; resources, Y.Z.; data curation, Y.T.; writing original draft preparation, Y.T.; writing—review and editing, Y.Z.; visualization, Y.T.; supervision, Y.Z.; project administration, Y.T.; funding acquisition, Y.T. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Natural Science project of Hunan Province, China, grant number 2020JJ5393 and Education Department of Hunan Province, China, grant number 21B0618.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** The authors declare no conflict of interest.
