液压制动管路中气液两相流流型聚类分析识别

利用汽车液压制动系统设计了一套用于检测液压制动管路中气液两相流的实验系统,提出了一种基于图像的灰度共生矩阵与系统聚类分析的气液两相流流型识别方法。该方法使用高速摄像机采集液压制动管路中的气液两相流流型图像,然后利用数字图像处理技术提取流型图像的灰度共生矩阵纹理特征参数,并将这些特征参数作为系统聚类分析的数据,进行系统聚类分析,最终实现流型的识别分类。实验结果表明,选用合适的样品间距和类间距的系统聚类分析模型,能够快速准确地对汽车液压制动系统管路中的4种典型流型进行识别分类,总体识别率达95.625%。该方法为液压制动管路中气液两相流流型参数的研究提供了一种新途径。

Identification of Gas-liquid Two-phase Flow Patterns in Hydraulic Braking Pipeline Based on Cluster Analysis

The automobile braking liquid is in a gas-liquid two-phase state. The gas-liquid two-phase flow in hydraulic braking pipeline is complicated and difficult to be detected. To detect the flow patterns in hydraulic braking pipeline effectively, an experimental bench was built up by mounting a transparent quartz pipe in a hydraulic braking system of automobile, and a flow pattern identification method was proposed based on the gray level co-occurrence matrix and hierarchical cluster analysis. Totally 160 images of gas-liquid two-phase flow patterns in the hydraulic braking pipeline were captured by a digital high speed camera, the feature parameters of gray level co-occurrence matrix of images were extracted by using image processing techniques, and then these feature parameters were used as source data, which were analyzed by the hierarchical cluster analysis method. In order to improve the accuracy of cluster analysis, different sample spaces and class spaces were compared to find the best combination of sample space and class space. Finally, the flow pattern intelligent identification was realized. The test results indicated that the brake fluid was a gas-liquid two-phase flow in hydraulic braking pipeline of automobile, whose flow patterns were recognized as bubbly flow, plug flow, slug flow and annular flow. The cluster analysis results also proved that the method was successful to identify the four typical flow patterns in hydraulic braking pipeline of automobile, and the whole identification accuracy was up to 95.625%. Especially for bubble flow and slug flow, their identification accuracies were 100%. Due to its high speed and high accuracy, the method provided an effective way for researching the flow patterns of gas-liquid two-phase flow in the hydraulic braking system.