AUTHOR=Yang Jun , Xie Xiongzhou , Tang Guowei , Wang Jianyong 

TITLE=Computational investigation on turbulent heat transfer of supercritical CO2 in the half-roughen horizontal pipe

JOURNAL=Frontiers in Energy Research

VOLUME=11

YEAR=2023

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2023.1249849

DOI=10.3389/fenrg.2023.1249849

ISSN=2296-598X

ABSTRACT=<p>To address the heat transfer degradation that occurs in the top section of horizontal pipes when sCO<sub>2</sub> fluid flows are heated, the upper half wall with higher temperatures is particularly roughened using uniform sand-grain roughness. The SST <inline-formula id="inf1"><mml:math id="m1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>k</mml:mi><mml:mo>−</mml:mo><mml:mi>ω</mml:mi></mml:mrow></mml:math></inline-formula> model is validated and used to simulate the horizontal sCO<sub>2</sub> heat transfer involving a variety of operating parameters and roughness heights. Results indicate that the half-roughen scheme is effective in significantly reducing higher temperatures of the entire upper wall and improving heat transfer homogeneity. The roughness height plays a crucial role, and an optimal value exists, which is largely influenced by the buoyancy strength and its local variations of horizontal sCO<sub>2</sub> flows under different conditions.</p>