Heat Transfer Characteristics of Supercritical Pressure CO2 in a Vertical Smooth Tube

被引：0

作者：

Zhang L. ^{[1
]}

Zhu B. ^{[1
]}

Wu X. ^{[1
]}

Xu J. ^{[1
]}

机构：

[1] Beijing Key Laboratory of Multiphase Flow and Heat Transfer (North China Electric Power University), Changping District, Beijing

来源：

Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | 2019年 / 39卷 / 15期

基金：

国家重点研发计划;

关键词：

Heat transfer; Heat transfer deterioration; Mixed convection; Numerical simulation; Supercritical carbon dioxide;

D O I：

10.13334/j.0258-8013.pcsee.181015

中图分类号：

学科分类号：

摘要：

Heat transfer characteristics of supercritical pressure carbon-dioxide (SCO2) in a heating vertical smooth tube were investigated experimentally and numerically. The experiment was performed in a 2m smooth tube with an inner diameter of 10mm, 4 cases from experimental database were chosen for analysis through numerical method. The comparison of numerical results showed that SST k-ω turbulent model gave better agreement than other turbulent models, so it was selected to stimulate the process of heat and mass transfer. Two heat transfer modes are defined respectively: normal heat transfer (NHT) and heat transfer deterioration (HTD). Thermal properties of supercritical fluid were also analyzed in this work. The result shows that the effects of flow acceleration are significant and the location of large Cp zone (a narrow temperature zone near pseudo-critical temperature (Tpc) whose Cp gradient varies sharply) in the radial section and the bulk temperature (Tb) can determine whether HTD would happen in the process of the heat transfer. In NHT cases, the large Cp zone occupies the buffer layer (5<y+<60) of the boundary layer in wall-bounded turbulent flow until Tb almost reach Tpc. In HTD cases, there is still a gap between Tb and Tpc while the large Cp zone mainly appears in the core region of flow with a decrease of Reynolds shear stress, which leads to the deterioration of turbulent kinetic energy and heat transfer. Heat transfer won't recover until the direction of Reynolds shear stress changes. © 2019 Chin. Soc. for Elec. Eng.

引用

页码：4487 / 4496

页数：9

共 33 条

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