Numerical study of the flow and heat transfer of supercritical CO2 flowing in various vertical serpentine tubes

被引：0

作者：

Huang T. ^{[1
]}

Li X. ^{[1
]}

Christopher D.M. ^{[2
]}

Ba Q. ^{[1
]}

Cheng L. ^{[1
]}

机构：

[1] Institute of Thermal Science and Technology, Shandong University, Jinan

[2] Key Laboratory of Thermal Science and Power Engineering of Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing

来源：

Qinghua Daxue Xuebao/Journal of Tsinghua University | 2020年 / 60卷 / 03期

关键词：

Convective heat transfer; Serpentine tubes; Supercritical CO[!sub]2[!/sub; Tube shape;

D O I：

10.16511/j.cnki.qhdxxb.2019.21.031

中图分类号：

学科分类号：

摘要：

As an environmentally friendly natural refrigerant, CO2 has been increasingly used as the working fluid in heat pumps. The flow and heat transfer of supercritical CO2 flowing in various serpentine tubes were modeled here to investigate the influence of the tube geometry on the heat transfer and to investigate the heat transfer enhancement mechanisms. Twelve full-size three-dimensional geometries were generated with different inner diameters and bend diameters to investigate the effects of the tube inner diameter and bend diameter on the flow and heat transfer of supercritical CO2 for a given flow flux. The results show that the heat transfer coefficient decreases as both the bend diameter and the inner diameter decrease. Thus, the outer wall temperature increases more rapidly and is higher with larger inner diameters and tube bend diameters. Finally, the effects of flow direction on the heat transfer were also studied to show that upward flow results in a higher heat transfer coefficient than downward flow for inner diameters larger than 1 mm. The present results are useful for enhanced heat exchanger designs to improve system efficiencies. © 2020, Tsinghua University Press. All right reserved.

引用

页码：263 / 270

页数：7

共 20 条

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