基于阵列热风激励的航发叶片近表面缺陷红外检测方法

航空发动机叶片的三维曲面结构、复杂的材料特性和特殊的冷却通道等，给叶片近表面缺陷的检测带来了困难。针对热激励源加热不均导致检测的红外热图效果差、缺陷识别率低的问题，提出了一种阵列热风激励的主动红外检测方法，改进并搭建一套可调阵列热风红外无损检测实验平台。通过设计阵列热风激励与局部热风激励的对比实验，并采用Canny算子进行缺陷边缘识别，证明了阵列热风激励主动红外检测方法的优势。通过实验分析不同材料下含裂纹试件的温度变化规律。实验结果表明：随热扩散系数增大，温升出现越早，表面最大温度呈下降趋势。通过利用检测实验平台对航空发动机叶片进行检测，揭示了导热性和隔热性缺陷的温度分布规律；其中导热性、隔热性和两者混合类型的缺陷检出率分别达到86.7%、93.3%、90%，也表明阵列热风激励红外检测方法能有效检测出航发叶片中的裂纹缺陷。

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.