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中文核心期刊

内分液结构调控竖直管间歇流型建模研究

MODEL RESEARCH ON MECHANISM OF MODULATED FLOW PATTERNS FOR VERTICAL UPFLOW

  • 摘要: 内分液流型调控管依靠微尺度网孔阻气通液的毛细力学特性,调控气液两相间歇流型以实现传热强化.基于Lockhart-Martinelli 分相模型以及Zuber-Findlay 漂移流动模型,建立描述内分液竖直管内流体动力特性的一维数学模型. 采用模型求解实验工况,计算结果与实验结果误差均在20% 以内. 计算发现,液速对流动现象起决定作用,而气速影响通过丝网的渗透程度. 在定性分析基础上,采用三角立方插值与最小二乘B 样条拟合获得了流动特性与气速、液速的定量函数关系. 据此得出结论,当Rel < 693 7 时,一定出现第1 类工况;当Rel > 693 7,且Reg < 67 时,可能会出现第2 类工况,此时较低的气速会促进第2 类工况的出现. 根据建立的模型与拟合关系式可实现内分液调控管的优化设计.

     

    Abstract: Due to the fact that micropores prevent gas while pump liquid according to their capillary force characteristics, the tube with mesh construction inside is proposed to modulate flow patterns and enhance heat transfer. Based on Lockhart-Martinelli's separated flow model and Zuber-Findlay's drift model, one-dimensional mathematic model is built to describe the flow dynamic behaviors in vertical flow pattern modulated tube. The experimental conditions are solved by mathematic model and the relative errors between model predicted and experimental results are no more than 20%. It is noted that liquid velocity plays a more important role on flow phenomena than gas velocity while gas velocity influences the degree of penetration through the mesh. Based on qualitative analysis, cubic interpolation and least squares B-spline fitting are used to obtain the quantitative function relationship between flow phenomena and superficial velocity. It comes to the conclusion that when Rel < 6937, there must be the first kind of condition, and when Rel > 6937 with Reg < 67, there can be the second kind of condition which is more likely to present at lower gas velocity. The mathematic model and quantitative function can contribute to the optimal design of flow pattern modulated tube.

     

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