摘要
提出了一种基于光场成像的气液两相流中气泡三维测量方法,解决了传统成像仅能进行二维测量的问题.利用光场相机记录气液两相流场的光场信息,结合光场计算成像技术获取两相流场内气泡的全聚焦图像和重聚焦图像序列.通过对全聚焦图像进行二值化分割等图像处理,获得气泡深度方向上的投影,对重聚焦图像序列进行清晰度评价,获得气泡的深度信息.基于获取的气泡投影以及深度信息,实现气泡三维重建,进而统计气泡群尺寸分布、空间位置及含气率等参数.开展了系统标定和试验研究,试验结果表明,截面含气率在深度方向上与气泡深度分布一致,在垂直方向上呈周期性震荡变化;随着气流量从0. 5 L/min增加至1. 1 L/min,气泡数量从28呈正比增加至72,气泡平均直径在气流量达到0. 9 L/min前保持在1. 56 mm左右,在0. 9 L/min后迅速增大,体含气率近似线性增加,气泡深度分布区间逐渐增大.气泡三维重建结果与气泡的产生规律一致,初步验证了方法的可行性.
A three-dimensional measurement method for bubble parameters in gas-liquid two-phase flow was proposed based on the light field photography for solving the problem that bubble parameters could only be measured in two-dimensional problems using conventional photography.The light field camera recorded the light field information of the gas-liquid two-phase flow,and then the total focus image and the refocused images of the bubbles in the two-phase flow field were obtained using a computational imaging technique.The image processing was performed by binarizing the total focus image to obtain the projection of bubbles in the depth direction and evaluating the sharpness of refocused images to obtain the depth of bubbles.Based on the bubble projection and depth information,the three-dimensional reconstruction of the bubbles was achieved,and the parameters,such as size distribution,spatial position and gas void fraction of bubbles were further calculated.The calibration and the experiment were made to evaluate the proposed method.Experimental results show that the cross-sectional void fraction in the depth direction is in agreement with the bubble depth distribution and oscillates periodically in the vertical direction.With the increase of gas flow rates from 0.5 L/min to 1.1 L/min,the amount of bubbles increases from 28 to 72;the average diameter of bubbles maintains about 1.56 mm before the gas flow rate reaches 0.9 L/min,after increasing sharply;the gas volume fraction rises approximately linearly,and the bubble depth interval increases gradually.The three-dimensional reconstruction results of bubbles are in good agreement with the law of bubble formation and distribution,thus verifying the feasibility of the proposed method.
作者
李庆浩
赵陆海波
张彪
唐志永
许传龙
Li Qinghao;Zhao Luhaibo;Zhang Biao;Tang Zhiyong;Xu Chuanlong(Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education,Southeast University,Nanjing 210096,China;Key Laboratory of Low-Carbon Conversion Science and Engineering,Shanghai Advanced Research Institute,Chinese Academy of Sciences,Shanghai 201210,China)
出处
《东南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2018年第6期1143-1151,共9页
Journal of Southeast University：Natural Science Edition
基金
国家自然科学基金资助项目(51676044)
江苏省自然科学基金资助项目(BK20150622
BK20150023)
中国科学院低碳转化科学与工程重点实验室开放课题资助项目(KLLCCSE-201703
SARI
CAS)
关键词
光场
气泡
三维重建
气液两相流
light field
bubbles
three-dimensional reconstruction
gas-liquid two-phase flow
