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水中气泡群图像灰度特征的研究
Study of Gray Feature of Water Bubbles Group Image
【作者】 杨林；
【导师】 杨龙滨；
【作者基本信息】 哈尔滨工程大学 ， 热能工程， 2015， 硕士
【摘要】 水中气泡广泛存在于许多领域,起着很重要的传热、传质作用,显然对水中气泡的研究有助于提高许多领域的生产效率。水中气泡已经成为两相流学科里一个热门的研究课题。然而大多数的研究都侧重于气泡的几何参数、运动参数、分离参数、含气率等参数。本文则借助于气泡群的灰度研究水中气泡群的气量以及分布特征。本文以水中气泡群的灰度为研究对象,搭建了气泡群图像灰度值实时采集系统。借助图像测量技术,对水中气泡群的灰度进行了测量。测量空气的体积流量范围为20.9-27.93 L/min、28.68-36 L/min、34.08-48.88 L/min。由整幅图片研究图像的灰度值,得到图片灰度值-时间曲线和体积流量-时间曲线有着较好的相似性。研究结果揭示水中气泡群的灰度值可以有效反映水中气泡群的气量。为研究灰度值的空间分布特征,本文从左向右,从上至下将每幅图片等分为9个区域。从左到右的三个区域,分别命名为区域左、中、右;从上到下的三个区域,分别命名为区域上、中、下。研究图像分块区域的灰度值,得出上、中、下3层区域的灰度值随高度分层。并且同一列的3个区域之间也有着较好的分层现象。当体积流量增大时,分层现象仍然存在。研究图像分块区域的灰度值,得出左、中、右3部分区域中,中部区域是图片中气泡群灰度值的核心区域,中部区域灰度值-时间曲线和灰度总值-时间曲线有着很好的相似性,中部区域是气泡群的最佳匹配区域。当体积流量增大时,中部区域仍然是气泡群灰度值的核心区域和最佳匹配区域。本文的研究均基于水中气泡群的灰度特征,研究结果揭示水中气泡群的灰度值可以有效反映水中气泡群的气量和分布特征,这种方法可用于测量未知区域气泡气量和分布特征。
【Abstract】 Bubble in water widely exists in many areas,plays an important role in heat and mass transfer,obviously the investigation of bubble in water helps to improve and increase productivity of these areas.The study of water bubbles also is a hot research topic in the two-phase discipline.However,most studies have focused on the bubble geometry parameters,motion parameters,separate parameters,void fraction.This paper studies gas volume and distribution of bubbles via the gray feature of bubbles cluster in water.In this paper,gray of bubbles cluster in water is regarded as the research topic;buliding a bubbles cluster image gray value real-time acquisition system.With the image measurement technology,gray of bubbles cluster in water are measured.The air volume flow rate range is 20.9-27.93 L / min,28.68-36 L / min and 34.08-48.88 L/min.By the entire picture,gray value of image is studied.The image gray value-time curve and air volume rate – time curve has a better similarity.The results reveal that the gray value of the water bubble clusters could reflect the volume flow.To study the spatial distribution of gray values,in the paper,from left to right,from top to bottom,each picture will be divided into nine regions.Three regions which from left to right are named as region left,middle and right;Three regions which from top to bottom are named as the region upper,middle and lower.Analyzing gray value of block area of image,obtain that the gray values present layered phenomenon along the height.Three regional gray value of each column also have good layered phenomenon.When the volume of traffic increases,the layered phenomenon between three areas also exits.Analyzing gray value of block area of image,the central area is the main area of gray value of the bubbles cluster,the gray value-time curve of the central area has a good similarity with the gray value-time curve,and the central area is the best match area of bubbles cluster.When the volume of traffic increases,the position that the central area is the main area of gray value of the bubbles cluster is not changed.And the central area also is the best match area of bubbles cluster.This paper’s investigations all base on the gray feature of bubbles cluster in water,the results reveal that the gray value of the water bubble clusters could reflect the volume flow and distribution of the water bubble clusters.This method will help test the volume flow and distribution of the water bubble clusters of unknown area.