基于图像检测技术的气液两相流截面含气率测量实验研究

Void Fraction of Vertical Gas-liquid Two-phase Flow Based on Image Detection Method

应用高分辨率工业相机配合远心镜头对内径10mm的小管道内的垂直下降环状流纵剖面拍摄采集原始图像,提出了一种通过数字图像处理技术计算平均截面含气率的计算模型。气液两相流首先通过入口接头沿切向方向进入实验段管道,被迫离心分离后形成垂直下降环状流进入实验段管道,随后利用环状流流型沿中心对称相对规则的特点,对采集图像进行阈值分割、小连通区域剔除、边缘提取和形态学开闭等操作求出截面含气率的采样总平均值,最后对比通过电站锅炉水力计算标准中滑速比模型计算的截面含气率理论计算值与实测值,相对误差均在±9%以内,具有较高的测量精度。

The original image was taken by using the high resolution industrial camera with the far heart camera in the small pipe in the inner diameter of 10mm.In this paper,a computational model for calculating the gas rate of an average cross section with digital image processing technology is proposed.Gas-liquid two phase flow first joint along the tangential direction through the inlet into the experimental section of the pipeline was forced to centrifugal separation after fall in vertical annular flow into the experimental section of pipeline,then used type annular flow along the center of symmetry relative rules,the characteristics of the collected image threshold segmentation,small connected regions excluding,edge detection and morphological opening and closing operation and the cross section of the total average rate of gas sampling.Finally,the calculation value and the measured value of the cross section ratio model calculated by the sliding speed ratio model are calculated by the hydraulic calculation standard of the power station boiler.The relative errors are within±9%with high accuracy.