Structural components of gas turbines, particularly the blades, sustain a variety of damages during the operation process. The most frequent cause of these damages are the overheating and thermal fatigue of the material. A primary technique to assess condition of the blades is the metallographic examination. In spite of the fact that metallographic analysis delivers much more information on the structure of examined blade material, it is a type of destructive test resulting in the destruction of the blade which makes further utilization of the item impossible. The paper has been intended to discuss non-destructive testing methods and to present capabilities of applying them to diagnose objectively changes in the microstructure of a turbine blade with computer software engaged to assist with the analyses. The following techniques are discussed: a visual method, based on the processing of images of the material surface in visible light, active thermography, based on the detection of infrared radiation, and the X-ray computed tomography. All these are new non-destructive methods of assessing technical condition of structural components of machines. They have been intensively developed at research centers worldwide, and in Poland. The computer-aided visual method of analyzing images enables diagnosis of the condition of turbine blades, without the necessity of dismantling of the turbine. On the other hand, the active thermography and the X-ray computed tomography, although more sensitive and more reliable, can both be used with the blades dismounted from the turbine. If applied in a complex way, the non-destructive methods presented in this paper, are expected to increase significantly probability of detecting changes in the blade’s condition, which in turn would be advantageous to reliability and safety of gas turbine service
1. Adamczyk J., Będkowski K. (2005), Digital methods in remote sensing, SGGW Publishing House, Ed. 1, Warsaw.
2. Błachnio J. (2011), Analysis of causes of decohesion of a gas turbine blade made of EI-867WD alloy, Aircraft Engineering and Aerospace Technology, An International Journal, Vol. 83 No 1, 14-20.
3. Błachnio J., Bogdan M. (2010), A non-destructive method to assess condition of gas turbine blades, based on the analysis of blade-surface image, Russian Journal of Nondestructive Testing, Vol. 46, No. 11, 860-866.
4. Błachnio J., Kułaszka A. (2009), Computer aided visual inspection of the technical condition of gas turbine blades during their operation period, Journal of KONES, Vol. 16, No. 3, 23-30.
5. Błachnio J., Pawlak W. (2011), Damageability of gas turbine blades - evaluation of exhaust gas temperature in front of the turbine using a non-linear observer, Advances in Gas Turbine Technology, In Tech, 435-464.
6. Bogdan M., Błachnio J., Derlatka M. (2009), Computer-aided method of diagnostics of gas turbine blades, Acta Mechanica et Automatica, Vol 3, No. 4, 13-16.
7. Burakowski T. (2002), The proposal of determining quantitative synergism in surface engineering, 3rd International Conference on Surface Engineering, Chengdu, P. R. China.
8. Chalimoniuk M., Błachnio J., Krzysztofik J. (2010), Analysis of the feasibility to investigate condition of gas turbine vanes by means of the radiographic method, Journal of KONBIN, No 1(13), 129-138.
9. Chalimoniuk M., Szczepanik R., Błachnio J. (2013), The rate of decohesion of a gas turbine blade as assessed with the X-ray computed tomography (CT), Journal of KONES, Vol. 20, No. 3, 89-96.
10. Electronic Instrument CT-X-ray (2011), The research report, Computer Tomography for Industrial Applications, YXLON. International.
11. EVEREST XLG3-Video Probe (2006), GE Inspection Technologies.
12. Holland S. D. (2011), Thermographic signal reconstruction for vibrothermography, Infrared Physics & Technology, 54, 503-511.
13. Karczewski, Z. (2008), Endoscopic diagnostics of marine engines, Diagnostyka, 3(47), 19-23.
14. Kułaszka A., Bogdan M., Błachnio J. (2011), New non-destructive methods of diagnosing health of gas turbine blades, Advances in Gas Turbine Technology, InTech, 465-498.
15. Maldague X. (2001), Theory and practice of infrared technology for nondestructive testing, John Wiley and Sons, New York.
16. Marsh S. (2013), Preventig fretting fatigue in blade dovetail roots by modifying geometry of contact surfaces, Power Transmission Engineering, 45-49.
17. Oliferuk W. (2008), Infrared thermography for nondestructive testing of materials and equipment, Gamma Office, Warsaw.
18. Pike L. M., Flower H. L. (2006), Gas turbine superalloy with improved fabricability. Advanced Materials and Processes, ASM International, Vol. 164, No. 6, 39- 43.
19. Pitkänen J. et al. (2001), NDT methods for revealing anomalies and defects in gas turbine blades, Proc 15th WCNDT, Rome.
20. Skočovský P., Podrábský T., Belan J. (2004), Operational degradation of aluminium-silicone layer of turbine blades made from Ni-based alloy, The Archive of Machinery Technology and Automation, Vol. 24, No. 1, 45-52.
21. Spychała J., Pawlak W., Kułaszka A., Błachnio J. (2013), Assessment of technical condition demonstrated by gas turbine blades by processing of images for their surfaces, Journal of KONBIN, 1 (21).
22. Szczepanik R., Rządkowski R. (2012), A study on the dynamics of aero engine blades under different operating conditions, Air Force Institute of Technology, Warsaw.
23. Wróbel Z., Koprowski R. (2004), Practice in image processing within the MATLAB software, EXIT Academic Publishing House, Warsaw.
24. Zieliński T. P. (2005), Digital signal processing - from theory to practice, Transport and Communications Publishers, Warsaw.
25. Żółtowski B., Cempel C. (2004), Machinery fault diagnosis engineering, Polish Society of Engineering Diagnosis, Warsaw.