化工学报 ›› 2017, Vol. 68 ›› Issue (8): 3049-3055.DOI: 10.11949/j.issn.0438-1157.20161643

• 流体力学与传递现象 • 上一篇    下一篇

直接接触式沸腾换热过程气泡混合均匀度评价

肖清泰1, 黄峻伟1, 潘建新2, 刘赟3, 徐建新1, 王华1   

  1. 1 昆明理工大学省部共建复杂有色金属资源清洁利用国家重点实验室, 云南 昆明 650093;
    2 曼彻斯特大学数学学院, 英国 曼彻斯特 M13 9PL;
    3 科罗拉多大学波德分校机械工程系, 美国 科罗拉多 80309
  • 收稿日期:2016-11-18 修回日期:2017-05-09 出版日期:2017-08-05 发布日期:2017-05-19
  • 通讯作者: 徐建新
  • 基金资助:

    国家自然科学基金项目(51666006,51406071);云南省科技领军人才培养计划项目(2015HA019)。

Assessing mixing uniformity of bubbles in direct-contact boiling heat transfer process

XIAO Qingtai1, HUANG Junwei1, PAN Jianxin2, LIU Yun3, XU Jianxin1, WANG Hua1   

  1. 1 State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, Yunnan, China;
    2 School of Mathematics, University of Manchester, Manchester M13 9PL, UK;
    3 Department of Mechanical Engineering, University of Colorado Boulder, Colorado 80309, USA
  • Received:2016-11-18 Revised:2017-05-09 Online:2017-08-05 Published:2017-05-19
  • Supported by:

    supported by the National Natural Science Foundation of China (51666006, 51406071) and the Scientific and Technological Leading Talent Projects in Yunnan Province (2015HA019).

摘要:

针对直接接触式沸腾换热过程中气泡群扰动的多相流体混合性能评价问题,提出一种基于图像处理技术与像素偏差理论量化混合复杂流体流型均匀性的精确检测与度量新方法。通过气泡群RGB图像的灰度矩阵进行偏差计算,精确地定量描绘了直接接触式换热过程中的气-液混合状态,其值大小反映了气泡群的分布状况,而不同工况下混合均匀时间的差异反映了不同多相体系的均匀性差异;对偏差序列进行正态性检验,发现其近似符合正态分布;运用混沌检测方法对序列进行混沌特征分析,发现整个混合过程是混沌的。通过一个简单的指标实现了复杂条件下气泡群的量化和表征,为多相流流型识别提供了新的分析思路并指导换热过程的混沌强化。

关键词: 直接接触式沸腾换热, 混沌, 成像, 气泡, 混合, 蒸发

Abstract:

In order to assess the mixing performance of multiphase flow disturbed by bubble swarms in direct-contact boiling heat transfer process, a novel technique based on image processing technique and pixel discrepancy theory was proposed to test and measure the mixing uniformity of complex fluids. The gray scale matrix of bubbles RGB image was used to calculate discrepancy. The mixed state of gas-liquid in direct-contact heat transfer was characterized accurately and quantitatively. The values reflect the distribution status of bubbles swarm. Different mixing uniformity of multiphase flow systems have different mixing time. Pixel discrepancy time series were employed for normality test and chaotic detection. It is found that the data is approximate normal distribution and the whole mixing processes are chaotic. A simple method was used to solve a complicated problem that the quantification and characterization of bubbles behavior under the complicated condition. The alternative route brings new insights to study multiphase flow identification and can act as a guide to enhancing the chaotic behavior of systems.

Key words: direct contact boiling heat transfer, chaos, imaging, bubble, mixing, evaporation

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