二相绕流流动特性的相关性和复杂性分析

Analysis on correlation and complexity of gas-liquid two-phase flow characteristics

从相关性和复杂性二方面对气液二相绕流管束的流型进行研究,分析了二相绕流流动特性。首先利用高速摄影仪采集2种节距比管束的不同流型图像,然后对图像处理提取气液二相流流型图像的复杂性测度(互相关系数,分形盒维数,Shannon信息熵),在此基础上研究了3种复杂性测度随气相折算速度变化的动力学特性和表征气液二相流流型的能力。实验结果表明:3种复杂性测度对流型变化是敏感的;通过分析互相关系数、分形维数和信息熵随二相流流动参数的变化规律,可以得到气液二相绕流流动力学结构特征,有助于二相流动力学机理的研究,为揭示二相流流型演化机理和定量标识流型提供了一种有效的辅助工具。

The correlation and complexity of gas-liquid two-phase flow pattern in in-line tube bundles were investigated.Two-phase flow characteristics across tube bundle were analyzed.Three complexity measures were extracted,including cross-correlation coefficient,fractal box dimension,and Shannon information entropy from flow pattern image signals of gas-liquid two-phase flow in two pitch tube bundles by using digital high speed video systems.Based on the above studies,the chaos dynamic characteristics of three complexity measures with gas superficial velocity and the recognition capability of gas-liquid two-phase flow pattern were analyzed.The experimental results indicate that the three complexity measures were sensitive to the flow pattern transition;through analyzing the rules of three complexity measures with the changes of gas superficial velocity,the dynamics structure of gas-liquid two-phase flow in tube bundle can be obtained,thus providing an efficient,supplementary assistant tool to reveal the flow pattern evolution mechanism of gas-liquid two-phase flow and quantitatively identify flow pattern.