Leak Localization Method Based on Infrared Thermography Using Local Entropy Difference Algorithm

Investigates the temperature characteristic of air leak flow and a novel leak localization method is put forward based on local entropy difference. The temperature drop in leak throttling process is derived from the expression of Joule-Thomson coefficient, which is corrected by compressibility factor. Test object is charged with cryogenic compressed air and its temperature field is acquired by infrared thermography. Leak positions can then be identified by local entropy calculation among multi-frame infrared images before and after inflation. It was proved by experiments that the method was effective and sensitive, especially in eliminating the influences of shape information and surface defects.