Infrared Detection of Near Surface Defects of Aeroengine Blade Based on Array Hot Air Excitation

The three-dimensional curved structure, complex material properties and special cooling channels of the aeroengine blades have brought difficulties to the detection of the near surface defects of the blades. Aiming at the problem that the uneven heating of the thermal excitation source leads to poor detection of infrared heat maps and low defect recognition, an active infrared detection method based on array hot air excitation is proposed, and a set of adjustable array hot air infrared non-destructive testing experimental platform is improved and built. By designing a comparative experiment between array hot air excitation and local hot air excitation, and using the canny operator to identify the edge of defects, the advantages of the array hot air excitation active infrared detection method are proved. The temperature variation law of the cracked specimens under different materials is analyzed through experiments. The experimental results show that as the thermal diffusion coefficient increases, the earlier the temperature rise occurs, and the maximum surface temperature shows a downward trend. Through the use of testing experimental platform to detect the aeroengine blades, the temperature distribution law of thermal conductivity and thermal insulation defects is revealed; the thermal conductivity, thermal insulation, and two mixed types of defects are detected The rates reached 86.7%, 93.3%, and 90% respectively. It also shows that the array hot-air excitation infrared detection method can effectively detect the crack defects in the blades of the aeroengine.