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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2022, Vol. 43 ›› Issue (12): 426271-426271.doi: 10.7527/S1000-6893.2021.26271

• Material Engineering and Mechanical Manufacturing • Previous Articles     Next Articles

Measurement method of turbine blade film aperture based on infrared thermal imaging and shrinkage law

XIA Kailong1,2, HE Qing1, ZHANG Yusheng1   

  1. 1. Surface Engineering Research Institute, Chinese Academy of Agricultural Mechanization Sciences, Beijing 100083, China;
    2. School of Aeronautics and Astronautics, Shanghai Jiao Tong University, Shanghai 200240, China
  • Received:2021-08-24 Revised:2021-09-07 Published:2021-10-14
  • Supported by:
    National Science and Technology Major Project (2017-Ⅶ-0007-0100)

Abstract: The film cooling structure is one of the three key technologies for design and manufacturing of high-pressure turbine blades of gas turbine engines. Quality control of the structure is of great significance to ensure the cooling effect, operational performance and structural reliability of the turbine blade. Based on the basic principles of infrared thermal imaging non-destructive testing, a set of multi-degree-of-freedom detection platform for the blade air film hole was built. A method for measuring the aperture was proposed, in which pulsed hot/cold air is used as the excitation source, the thermal imager is used as the signal acquisition equipment, and the image processing technology is employed to measure the aperture. 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. High precision aperture value was obtained, with the average difference from the standard plug gauge measurement result being less than 4.40%. The shrinkage law after applying thermal barrier coating was 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 4.0%. The average shrinkage porosity after coating the ceramic layer is 16.2%.

Key words: infrared thermal imaging, film cooling hole, thermal barrier coatings, non-destructive testing, image processing

CLC Number: