化工学报 ›› 2023, Vol. 74 ›› Issue (3): 1062-1072.DOI: 10.11949/0438-1157.20221426

• 流体力学与传递现象 • 上一篇    下一篇

冷却条件下渐扩/渐缩管内超临界压力二氧化碳的传热特性

朱兵国1(), 何吉祥1, 徐进良2, 彭斌1   

  1. 1.兰州理工大学机电工程学院,甘肃 兰州 730050
    2.华北电力大学低品位能源多相流与传热北京市重点实验室,北京 102206
  • 收稿日期:2022-11-01 修回日期:2023-02-21 出版日期:2023-03-05 发布日期:2023-04-19
  • 通讯作者: 朱兵国
  • 作者简介:朱兵国(1988—),男,博士,讲师,zhubg@lut.edu.cn
  • 基金资助:
    甘肃省青年科学基金项目(22JR5RA283)

Heat transfer characteristics of supercritical pressure CO2 in diverging/converging tube under cooling conditions

Bingguo ZHU1(), Jixiang HE1, Jinliang XU2, Bin PENG1   

  1. 1.School of Mechanical & Electrical Engineering, Lanzhou University of Technology, Lanzhou 730050, Gansu, China
    2.Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy, North China Electric Power University, Beijing 102206, China
  • Received:2022-11-01 Revised:2023-02-21 Online:2023-03-05 Published:2023-04-19
  • Contact: Bingguo ZHU

摘要:

采用SST k-ω湍流模型,数值计算了冷却条件下超临界压力二氧化碳(SCO2)在三种水平管(等截面管、渐扩管和渐缩管)内的传热特性,研究了不同运行参数(压力、质量流量及热通量)对传热性能的影响。结果表明,与等截面管相比,渐扩管有效地强化了传热,采用渐扩管时,SCO2的总传热系数最大提高了47.98%。然而,相比等截面管,渐缩管却削弱了传热。最后,从类冷凝和湍流场分布的角度阐明了传热强化的物理机理。为SCO2冷却器的优化设计提供了新的思路和理论指导。

关键词: 超临界二氧化碳, 渐扩/渐缩管, 传热强化, 类冷凝, 湍流

Abstract:

Using the SST k-ω turbulence model, the heat transfer characteristics of supercritical carbon dioxide (SCO2) in three kinds of horizontal tubes (uniform cross-section tube, diverging tube and converging tube) were numerically calculated under cooling conditions, and different operating parameters were studied (pressure, mass flow and heat flux) on heat transfer performance. The computational results demonstrate that the diverging tube effectively strengthen heat transfer compared with the uniform cross-section tube. A maximum improvement of 47.98% in overall heat transfer coefficient can be observed with the employment of diverging tubes. However, the converging tube weakens the heat transfer. According to the distribution of quasi-liquid film and turbulent kinetic energy, the physical mechanism of heat transfer enhancement is clarified by the dual-effect of quasi-liquid film and turbulent kinetic energy on this account. Our work provides a new idea and theoretical guidance for the optimal design of SCO2 cooler.

Key words: supercritical carbon dioxide, diverging/converging tube, heat transfer enhancement, pseudo-condensation, turbulent flow

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