红外热成像技术在孔隙尺度下多孔介质相变过程表征中的应用与优化研究  

Application of Infrared Thermography for Characterizing Phase Change Process of Porous Media at Pore Scale

作　　者：王淑 冷航 陈彦伶 王昌涛 陈周林 杨英英 WANG Shu;LENG Hang;CHEN Yanling;WANG Changtao;CHEN Zhoulin;YANG Yingying(School of Energy and Power Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China;Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering,Shanghai 200093,China)

机构地区：[1]上海理工大学能源与动力工程学院,上海200093 [2]上海市动力工程多相流动与传热重点实验室,上海200093

出　　处：《红外技术》2022年第3期294-302,共9页Infrared Technology

基　　金：国家自然科学基金青年基金(52006146);上海市青年科技英才扬帆计划(19YF1434700);上海高校青年东方学者岗位计划。

摘　　要：红外热成像技术是一种应用广泛、发展较快的新型数字化无损检测技术,但其目前仍存在测量精度较低、图像噪声影响较大、数据量巨大等缺点。本文利用红外热成像技术,在孔隙尺度下对多孔材料内石蜡和水的相变过程进行了表征,并对红外热成像测温精度和相界面的表征进行了优化。首先通过添加反射表面(褶皱的铝箔)获取测试过程中环境反射温度,以修正目标物体温度;同时通过引导滤波和主成分热像法(Principal component thermography,PCT)对红外热成像图片降噪,提高红外热像仪对温度场及相界面的检测精度。实验结果表明:环境反射温度修正法可以排除测试环境温度变化对红外测温结果的影响;引导滤波法选取合适的滤波半径和滤波参数后相界面轮廓更加清晰,并取得较好的降噪效果;主成分热像法除了降噪效果好,使相界面更清晰,并使处理数据量减少了4个量级。上述3种优化方法为红外热成像技术在孔隙尺度下多孔介质相变过程表征中的应用提供了技术支持。Infrared thermography(IRT)is a new type of digital nondestructive testing technology that has developed rapidly and has found wide use.However,it still has some shortcomings,such as low accuracy,image noise,and requires a large amount of data.In this study,the phase change processes of paraffin and water in porous materials are characterized by IRT technology at pore scale,and the temperature measurement accuracy and phase interface characterization are optimized.First,the reflective surface(wrinkled aluminum foil)is added to obtain the environmental reflective temperature in the test process to correct the target object temperature;subsequently,guided filtering and principal component thermography(PCT)are used to reduce the noise of IRT images to improve the detection accuracy of the infrared thermal imager for temperature field and phase interface.The experimental results show that the temperature measured by the environmental reflection temperature correction method is closer to that measured by a thermocouple after eliminating the influence of changing environmental temperature;after selecting an appropriate filter radius and filter parameters,the contour of phase interface is clearer,and a better noise reduction effect is obtained.In addition to the good noise reduction effect,PCT makes the phase interface clearer and reduces the amount of processed data by four orders of magnitude.These three processing methods provide better optimization methods and theoretical support for infrared thermal imaging technology to characterize the phase transition process of porous media at the pore scale.

关 键 词：红外无损检测 孔隙尺度 多孔介质 相变过程 降噪优化 

分 类 号：TN219[电子电信—物理电子学]