CIESC Journal ›› 2015, Vol. 66 ›› Issue (3): 942-948.DOI: 10.11949/j.issn.0438-1157.20141622

• 流体力学与传递现象 • 上一篇    下一篇

毛细管内气液Taylor流动的气泡及阻力特性

张井志1,2, 李蔚1   

  1. 1 浙江大学能源工程学院, 浙江 杭州 310027;
    2 浙江大学能源工程学院, 先进航空发动机协同创新中心, 浙江 杭州 310027
  • 收稿日期:2014-10-28 修回日期:2014-12-11 出版日期:2015-03-05 发布日期:2015-03-05
  • 通讯作者: 李蔚
  • 基金资助:
    浙江省自然科学基金项目(Z13E060001);国家科技支撑计划项目(2012BAA10B01)。

Bubble and frictional characteristics of gas-liquid Taylor flow in capillary tube

ZHANG Jingzhi1,2, LI Wei1   

  1. 1 College of Energy Engineering, Zhejiang University, Hangzhou 310027, Zhejiang, China;
    2 Co-Innovation Center for Advanced Aero-Engine, College of Energy Engineering, Zhejiang University, Hangzhou 310027, Zhejiang, China
  • Received:2014-10-28 Revised:2014-12-11 Online:2015-03-05 Published:2015-03-05
  • Supported by:
    supported by the Natural Science Foundation of Zhejiang Province (Z13E060001) and the Chinese National Key Technology R&D Program (2012BAA10B01).

摘要: 采用相对坐标系方法,研究毛细管(d 2mm)内充分发展垂直上升气液Taylor流动,分析两种工作介质下Taylor气泡的形状、上升速度、液膜厚度以及压降特性。结果表明:随着两相表观速度(Vtp)增大,Taylor气泡长度增大,气泡尾部曲率半径增大。气泡长度及内部回流区随着气泡体积分数(ξg)增大而增大,量纲1液膜厚度与气泡上升速度与毛细数(Ca)正相关,模拟结果与经验公式吻合较好。摩擦阻力因子(fc)随Vtpξg的增大而降低,N2/乙二醇为工质的Taylor流动fc低于单相情况,而N2/水为工质的Taylor流动fc高于单相情况。Kreutzer等的流型依赖公式以及Lockhart等的分离模型可较好预测本文的两相压降,模拟结果与预测值的误差在±10%以内,常规通道所推荐C 5仍然适用于本文毛细管情况。

关键词: Taylor气泡, 气液两相流, 数值模拟, 毛细管, 相对坐标系

Abstract: In order to obtain the frictional characteristics of fully developed Taylor flow in the vertical capillary tube, numerical simulations of the flow in the capillary tube with diameter of 2 mm were conducted by using the moving frame reference method. The shape, rising velocity of Taylor bubble, liquid film thickness and pressure drop were obtained using two different working fluids and analyzed. Simulation results showed that the length of Taylor bubble and the radius of curvature increased with increasing two-phase superficial velocity Vtp. The length of Taylor bubble also increased with increasing gas void ξg, while the nose and tail of Taylor bubble were independent of ξg. Dimensionless thickness of liquid film and rising velocity of Taylor bubbles were proportional to capillary number Ca. Friction factor fc decreased with increasing Vtp and ξg. The fc of Taylor flow with N2/ (CH2OH)2 as working fluid was lower than that of single phase with the same Vtp, while the fc for N2/H2O was higher than that of single phase. The model proposed by Lockhart and Martinelli, and the flow pattern dependent model proposed by Kreutzer et al. could predict the pressure drop obtained from simulation with an error of ±10%. The Chisholm number C 5 which was recommended for conventional tube when both phases were laminar was also reasonable for the capillary tube in the simulation work.

Key words: Taylor bubble, gas-liquid flow, numerical simulation, capillary tubes, relative coordinate

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