东北大学学报（自然科学版）

东北大学学报(自然科学版) ›› 2013, Vol. 34 ›› Issue (8): 1175-1178.DOI: -

• 机械工程 • 上一篇    下一篇

亚临界CO2在缩放喷管中降压膨胀的数值模拟

马娟丽1，孙皖1，刘昌海1，侯予1,2   

  1. (1.西安交通大学能源与动力工程学院，陕西西安710049；2.西安交通大学动力工程多相流国家重点实验室，陕西西安710049)
  • 收稿日期:2013-03-14 修回日期:2013-03-14 出版日期:2013-08-15 发布日期:2013-03-22
  • 通讯作者: 马娟丽
  • 作者简介:马娟丽(1981-)，女，陕西渭南人，西安交通大学博士研究生；侯予(1973-)，男，河北唐山人，西安交通大学教授，博士生导师.
  • 基金资助:
    国家自然科学基金资助项目(50976082)；高等学校博士学科点专项科研基金资助项目(20090201110006)；中央高校基本科研业务费专项资金资助项目.

Numerical Simulation of Decompression Expansion of Subcritical CO2 Through ConvergingDiverging Nozzle

MA Juanli1， SUN Wan1， LIU Changhai1， HOU Yu1,2   

  1. 1. School of Energy and Power Engineering， Xi’an Jiaotong University， Xi’an 710049， China; 2. State Key Laboratory of Multiphase Flow in Power Engineering， Xi’an Jiaotong University， Xi’an 710049， China.
  • Received:2013-03-14 Revised:2013-03-14 Online:2013-08-15 Published:2013-03-22
  • Contact: HOU Yu
  • About author:-
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摘要： 忽略两相间的滑移速度，采用Fluent中的混合模型对亚临界CO2过冷液体进入缩放喷管降压膨胀产生气泡的两相流动过程进行了二维数值模拟.其中，气液两相间单位体积内的质量传递率采用空化模型理论进行计算.计算工况如下:喷管液体CO2进口压力为61MPa，温度为29315K，喷管出口为两相状态.计算结果显示，CO2工质流经喉部时，压力急剧降低，相间的质量传递率达到最大值，CO2工质发生相变；工质进入扩散段后，随着压力降低，气体份额不断增大，喷管出口压力为165MPa时，气体体积份额约为093.数值模拟值与实验值对比结果为，计算压力与实测压力值最大误差不超过101%，计算温度与实测温度值最大误差不超过19%.数值模拟揭示了亚临界CO2在喷管中的气液两相膨胀过程.

关键词: 亚临界CO2, 气-液两相流, 缩放喷管, CO2喷射器, 质量传递率, 空化模型理论

Abstract: Twophase flow generated from expansion of subcooled subcritical CO2 when flowing through a convergingdiverging nozzle was studied numerically using the mixture model of the Fluent with the sliding velocity neglected. Mass transfer rate between the two phases was calculated with the cavitation model under 61MPa and 29315K at the nozzle inlet. The results show that phase change occurs at the throat and the pressure drops steeply with the mass transfer rate reaching the maximum. The vapor volume fraction increases with decrease of pressure when the CO2 flows through the nozzle diverging section. When the pressure at nozzle exit gets to 165MPa， the volume fraction reaches 093. The comparison of calculated and experimental results show that the maximum relative error of pressure is less than 101% and that of temperature is less than 19%. Mechanism of the twophase flow expansion process of the subcooled CO2 through a convergingdiverging nozzle was well described by numerical simulation.

Key words: subcritical CO2, gasliquid twophase flow, convergingdiverging nozzle, CO2 ejector, mass transfer rate, cavitation model theory

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