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过程工程学报 ›› 2023, Vol. 23 ›› Issue (12): 1617-1626.DOI: 10.12034/j.issn.1009-606X.222454

• 研究论文 • 上一篇    下一篇

障碍微通道内气液两相流运动特性

霍元浩， 杨刚， 张会臣*   

  1. 大连海事大学船舶与海洋工程学院，辽宁 大连 116026
  • 收稿日期:2022-12-13 修回日期:2023-04-03 出版日期:2023-12-28 发布日期:2024-01-01
  • 通讯作者: 张会臣 hczhang@dlmu.edu.cn
  • 基金资助:
    国家自然科学基金资助项目

Flow characteristics of gas-liquid two-phase flow in microchannel with obstacles

Yuanhao HUO,  Gang YANG,  Huichen ZHANG*   

  1. Naval Architecture and Ocean Engineering College, Dalian Maritime University, Dalian, Liaoning 116026, China
  • Received:2022-12-13 Revised:2023-04-03 Online:2023-12-28 Published:2024-01-01
  • Contact: 会臣 无张 hczhang@dlmu.edu.cn

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摘要： 微通道内障碍对气液两相流压力降和气泡形状具有显著影响。采用实验和数值模拟的方法探究了微通道内障碍位置对氮气/水气液两相流运动特性的影响，分析了不同气液流量条件下障碍微通道内压力降和气泡长度的变化规律。结果表明，障碍微通道内压降高于无障碍微通道，当障碍位于中心位置时，压降最大，这是由于障碍后产生涡流所致，且压降与涡流长度正相关；障碍微通道气泡长度相对于无障碍通道变化均在25%以内，且随着障碍趋近于中心位置，气泡长度变短；不同工况条件下气泡通过障碍时的形状变化呈现三种现象：回缩不发生破裂、回缩发生破裂和不回缩直接破裂。回缩不发生破裂时，回缩长度随毛细数增大而增大；回缩发生破裂时，回缩长度随毛细数增大而减小；回缩长度减小到0时，变为不回缩直接破裂。回缩长度的变化范围随着障碍趋近于中心位置逐渐变大。通过所有障碍过程中，不同工况条件下展现出不同的破裂与合并规律。数值模拟揭示了障碍后产生旋涡长度不同导致压降不同，在气泡破裂瞬间压力存在剧烈变化。通过障碍时，气泡形状的变化源于其周围液相流速的变化，障碍两侧子通道内的速度不同决定两子气泡经过障碍后的不同规律。

关键词: 障碍微通道, 压力降, 气泡长度, 数值模拟, 速度场

Abstract: The obstacles in the microchannel have a significant impact on the pressure drop and bubble shape of gas-liquid two-phase flow. In this work, experimental and numerical simulation methods are used to explore the effect of obstacles in the channel on the movement characteristics of nitrogen/water gas-liquid two-phase flow in the microchannel. The variations of pressure drop and bubble length under different gas and liquid flow rates in microchannel with obstacles are analyzed. The results show that the pressure drop in the obstacle microchannel is higher than that in the barrier free microchannel, and the maximum pressure drop occurs with the obstacle in the center. Through numerical simulation analysis, this is due to the vortex generated after the obstacle, and the pressure drop is positively related to the vortex length. The bubble length of the obstacle microchannel changes within 25% compared to the barrier free channel, and the bubble length becomes shorter as the obstacle approaches the center. Under different flowing conditions, there are three phenomena when bubbles pass through obstacles, including retraction without rupture, retraction with rupture, and direct rupture without retraction. The retraction lengths increase with capillary number increasing in retraction without rupture. The retraction lengths reduce with capillary number increasing in retraction with rupture. When the retraction length decreases to 0, it become a direct fracture without retraction. The variation range of retraction length gradually increases as the obstacle approaches the center. When passing through all obstacles, different breaking and merging laws are displayed under different working conditions. By numerical simulation, different vortex lengths after the obstacle result in different pressure drops, and there exists sever change at the moment of bubble rupture. When passing through the obstacle, the change of bubble shape is affected by the change of liquid phase velocity around it, different velocities in the sub channels on both sides of the obstacle determine the different rules of the two sub bubbles after passing through the obstacle.

Key words: microchannel with obstacles, bubble length, numerical simulation, velocity field