Development of non-destructive heat resistance evaluation system for TBC on gas turbine blade

Fujii, Tomoharu; Takahashi, Toshihiko; Sakai, Eiji; Fujioka, Terutaka; Chandra, Budi; Simmons, Kathy; Pickering, Stephen; Tittel, Marc

Abstract

The use of thermal barrier coatings (TBCs) is the key technique for realizing high-efficiency gas turbine combined cycles. Hence, TBCs are applied to various hot gas path components such as combustors, blades, and vanes. The application of a TBC causes a significant decrease in the temperature of the base metal surface. Consequently, the lifetime of the component is increased. However, it is reported that under high-temperature operating conditions, the heat resistance of the TBC decreases gradually because of sintering and erosion of the TBC layer. Accurate evaluation of changes in the TBC heat resistance is very important for evaluating the residual lifetime of a given component. We have previously developed a nondestructive technique for measuring the heat resistance of TBCs applied on the inner surface of a combustion liner. In this technique, the TBC surface is heated by a laser beam, and the temperature change of this heated point is measured by an IR camera. The heat resistance is calculated from the measured temperature. On the basis of this concept, we have made improvements to this technique so that it can be used to measure the heat resistance of a TBC layer on a blade surface. However, several difficulties are encountered whenusing this technique for the abovementioned purpose. For example, the blade has a three-dimensional (3D) surface and complex internal cooling paths, as opposed to the combustion liner, which has a simple cylindrical shape. Hence, it is difficult to keep the same heating condition at any surface. To overcome these difficulties, we propose a new concept and develop a system for measuring the heat resistance of the TBC layer on a blade. This system is mainly composed of a carbon dioxide laser, a robot arm, and an IR camera. In this paper, we present an overview of the developed system. Copyright © 2010 by ASME.

• Presentation Conference Type: Conference Paper (published)
• Conference Name: Proceedings of the ASME Turbo Expo
• Start Date: Jun 14, 2010
• End Date: Jun 18, 2010
• Acceptance Date: Jun 14, 2010
• Publication Date: Dec 1, 2010
• Peer Reviewed: Peer Reviewed
• Volume: 3
• Pages: 125-131
• Book Title: Volume 1: Aircraft Engine; Ceramics; Coal, Biomass and Alternative Fuels; Education; Electric Power; Manufacturing Materials and Metallurgy
• DOI: https://doi.org/10.1115/GT2010-22631
• Keywords: scavenge, bearing chamber, gas turbine, multiphase flow
• Public URL: https://uwe-repository.worktribe.com/output/978417
• Publisher URL: http://dx.doi.org/10.1115/GT2010-22631
• Additional Information: Title of Conference or Conference Proceedings : ASME Turbo Expo 2010: Power for Land, Sea, and Air