气体射流不稳定性的建模和实验研究  

Experiments and modelling of gas jet instability using image processing and chaos theory

作　　者：刘泛函[1,2] 王华[1,2] 徐建新[1,3] 

机构地区：[1]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]昆明理工大学冶金与能源工程学院,云南昆明650093 [3]昆明理工大学质量发展研究院,云南昆明650093

出　　处：《化工进展》2016年第11期3433-3440,共8页Chemical Industry and Engineering Progress

基　　金：国家重点基础研究发展计划(2014CB460605);国家自然科学基金(51174105;51206071;51366005;51406071;51206071)项目

摘　　要：基于图像处理技术和混沌理论,提出了一种气体射流图像的量化方法,用以反映气液混合性能。本文使用大津法来获得自适应阀值,并得到最佳的图像分割效果。混合性能(M)用以表征气体射流的空间分布,其定义为气体射流像素占比(W)与射流区域内的灰度标准差(N)之比。通过混合性能的非线性时间序列来表征射流喷射过程的不稳定变化,并得到了以下结果:在射流区制下,射流的稳定性随着修正弗鲁德数的增加而增加,证明了所提出方法的可靠性;其次,在同一工况中射流的稳定性与最大李雅普诺夫指数之间具有明显的线性关系,其线性相关系数为0.954,并构建了射流的稳定性与最大李雅普诺夫指数的线性关系模型。证明了最大李雅普诺夫指数不仅可以判断混合过程是否呈现混沌状态,而且其数值的大小反应了气体射流稳定性的强弱。Based on image processing technology and chaos theory, a novel method for quantitative characterization of gas jet images was proposed,which reflects the mixing performance. The Otsu method was used to find the best threshold value and hence the best segmented images. The mixing performance（M） is defined as the ratio of proportion of gas jet pixels（W） to standard deviation of the grayscale values in gas jet region（N） for characterizing spatial distribution of gas jet. Unsteady motions of the gas jet were characterized by the nonlinear time series of the mixing performances. As have shown,the stability of gas jet（1/V） decrease with the increasing modified Froude number under jetting regime,which confirms the validity of our approach. On top of that,the linear relation between stability and largest Lyapunov exponent（LLE） was obvious with a correlation coefficient of 0.954. For further research a linear model of stability and LLE were constructed. The results showed that the LLE can not only judge the mixing process is nonchaotic or chaotic,also the numerical size of LLE reflected the stability of gas jet.

关 键 词：多相流 混合 稳定性 气泡 混沌 

分 类 号：TF02[冶金工程—冶金物理化学]