研究了一种基于红外图像融合技术进行气体泄漏点定位的方法.通过对气体泄漏热传导过程的有限元模拟和泄漏节流温差的焦耳.汤姆逊系数计算,建立了被测对象的温度场模型.实验采用主动式冷却器对气体进行降温处理以增强现象,利用热像仪分别采集金属与非金属对象充入压缩空气前后的红外图像, 根据不同材质对象的导热特性分别建立泄漏诊断阈值并进行熵值融合计算,从而定位泄漏点.仿真和实验结果表明,红外热像图可以灵敏地反映泄漏点处温度变化,熵融合算法能够快速、准确地提取出多种材质对象的泄漏位置,并且有效克服了被测工件表面缺陷对温度场及定位的干扰.%An air leakage localization method based on infrared image fusion was investigated. Modeling and simulation of heat transfer coupled with steady air-leak flow were addressed by the finite element method. The temperature difference in leak throttling proeess was derived from the expression of Joule-Thomson coefficient. In the experiments, metallic and metalloid test objects were charged with cryogenic compressed air respectively, which enhanced the phenomenon, and their temperature fields were acquired by an infrared camera. Leak diagnostic criterion was set as different values referring to the thermal eonductivities of various tested materials, and entropy fusion operation among the infrared images captured before and atter inflation was conducted. Then, the leak positions were located by a certain strategy. The advantages of the method were demonstrated by experiment, especially in eliminating the interference of surface defects and the influence of shapes by employing the entropy fusion algorithm.
展开▼
