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基于红外热成像的涡轮叶片气膜孔孔径测量方法及缩孔规律研究

夏凯龙1,何箐2,张雨生2   

  1. 1. 上海交通大学
    2. 中国农业机械化科学研究院
  • 收稿日期:2021-08-24 修回日期:2021-10-13 出版日期:2021-10-14 发布日期:2021-10-14
  • 通讯作者: 何箐
  • 基金资助:
    国家科技重大专项

Research on the Measurement Method of Turbine Blade Film Hole Aperture Based on Infrared Thermal Imaging and the Shrinkage Law

  • Received:2021-08-24 Revised:2021-10-13 Online:2021-10-14 Published:2021-10-14

摘要: 气膜冷却结构是燃气涡轮发动机高压涡轮叶片的三大关键设计制造技术之一,其质量控制对保证涡轮叶片的气冷效果、使役性能和结构可靠性具有重要意义。基于红外热成像无损检测的基本原理,搭建了一套多自由度叶片气膜孔检测平台,提出了一种以脉冲热/冷空气为激励源、热像仪为信号采集设备和图像处理技术为实现途径的孔径测量方法,同时考虑气膜孔轴线特征和叶身型面曲率因素,设置正弦和动态余弦修正因子优化了以霍夫圆检测函数为核心的孔径测量算法,得到了与标准塞规测量结果平均差值小于4.4%的高精度孔径值,并总结了涂覆热障涂层后的缩孔规律,结果表明:涂覆粘结层对气膜孔孔径的影响不大,相对原始孔径的平均缩孔率小于4%;涂覆陶瓷层后的平均缩孔率则为16.2%。

关键词: 红外热成像, 叶片气膜孔, 无损检测, 图像处理

Abstract: The film cooling structure is one of the three key technologies of design and manufacturing for high-pressure turbine blades of gas turbine engines. Its quality control is of great significance to ensure the cooling effect, operational performance and structural reliability of the turbine blades. Based on the basic principles of infrared thermal imaging non-destructive testing, a set of multi-degree-of-freedom blade air film hole detection platform has been built, and a method for measuring aperture has been proposed, which applies pulsed hot/cold air as excitation source, thermal imager as signal acquisition equipment and image processing technology to achieve the approach.At the same time, considering the characteristics of the air film hole axis and the curvature of the blade body, the sine and dynamic cosine correction factors are set to optimize the hole measurement algorithm based on the Hough circle detection function, and the high precision aperture value has been obtained, whose average difference with the standard plug gauge measurement result is less than 4.4%. Also, the shrinkage law after applying thermal barrier coating has been summarized. The result shows that the coating of the adhesive layer has little effect on the pore diameter of the air film, and the average shrinkage rate relative to the original pore diameter is less than 4 %.The average shrinkage porosity after coating the ceramic layer is 16.2%.

Key words: infrared thermal imaging, firm cooling holes, non-destructive testing, image processing

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