Temperature monitoring of through-thickness temperature gradients in thermal barrier coatings using ultrasonic guided waves
Temperature monitoring of through-thickness temperature gradients in thermal barrier coatings using ultrasonic guided waves
Ultrasonic guided waves offer a promising method of monitoring the online temperature of plate-like structures in extreme environments, such as aero-engine nozzle guide vanes (NGVs), and can provide the resolution, response rate, and robust operation that is required in aerospace. Previous investigations have shown the potential of such a system but the effect of the complex physical environment on wave propagation is yet to be considered. This article uses a numerical approach to investigate how thermal barrier coatings (TBCs) applied to the surface of many components designed for extreme thermal conditions will affect ultrasonic guided wave propagation, and how a system can be employed to monitor through-thickness temperature changes. The top coat/bond coat boundary in NGVs has been shown to be a temperature critical point that is difficult to monitor with traditional temperature sensors, which highlights the potential of ultrasonic guided waves. Differences in application method and layer thickness are considered, and analysis of through-thickness displacement profiles and dispersion curves are used to predict signal response and determine the most suitable mode of operation. Heat transfer simulations (COMSOL) have been used to predict temperature gradients within a TBC, and dispersion curves have been produced from the temperature dependant material properties. Time dependant simulations of wave propagation are in good agreement with dispersion curve predictions of wave velocity for the two lowest order modes in three thicknesses of TBC top coat (100, 250, and 500 μm). When wave velocity measurements from the simulations are compared to dispersion curves generated at isotropic temperatures, the corresponding temperature represents the average temperature of a gradient system well. Such a measurement system could, in principle, be used in conjunction with surface temperature measurement systems to monitor through-thickness temperature changes.
Ultrasonic guided waves, Thermal barrier coatings, Temperature monitoring, Nozzle guide vanes
Yule, Lawrence
87c4d44f-a50a-4ae4-8084-50de55b9a24c
Harris, Nicholas
237cfdbd-86e4-4025-869c-c85136f14dfd
Hill, Martyn
0cda65c8-a70f-476f-b126-d2c4460a253e
Zaghari, Bahareh
5c3f92a5-3143-4dad-bcb4-7e34ebd4901f
Yule, Lawrence
87c4d44f-a50a-4ae4-8084-50de55b9a24c
Harris, Nicholas
237cfdbd-86e4-4025-869c-c85136f14dfd
Hill, Martyn
0cda65c8-a70f-476f-b126-d2c4460a253e
Zaghari, Bahareh
5c3f92a5-3143-4dad-bcb4-7e34ebd4901f
Yule, Lawrence, Harris, Nicholas, Hill, Martyn and Zaghari, Bahareh
(2024)
Temperature monitoring of through-thickness temperature gradients in thermal barrier coatings using ultrasonic guided waves.
Journal of Nondestructive Evaluation, 43 (1), [22].
(doi:10.1007/s10921-023-01038-5).
Abstract
Ultrasonic guided waves offer a promising method of monitoring the online temperature of plate-like structures in extreme environments, such as aero-engine nozzle guide vanes (NGVs), and can provide the resolution, response rate, and robust operation that is required in aerospace. Previous investigations have shown the potential of such a system but the effect of the complex physical environment on wave propagation is yet to be considered. This article uses a numerical approach to investigate how thermal barrier coatings (TBCs) applied to the surface of many components designed for extreme thermal conditions will affect ultrasonic guided wave propagation, and how a system can be employed to monitor through-thickness temperature changes. The top coat/bond coat boundary in NGVs has been shown to be a temperature critical point that is difficult to monitor with traditional temperature sensors, which highlights the potential of ultrasonic guided waves. Differences in application method and layer thickness are considered, and analysis of through-thickness displacement profiles and dispersion curves are used to predict signal response and determine the most suitable mode of operation. Heat transfer simulations (COMSOL) have been used to predict temperature gradients within a TBC, and dispersion curves have been produced from the temperature dependant material properties. Time dependant simulations of wave propagation are in good agreement with dispersion curve predictions of wave velocity for the two lowest order modes in three thicknesses of TBC top coat (100, 250, and 500 μm). When wave velocity measurements from the simulations are compared to dispersion curves generated at isotropic temperatures, the corresponding temperature represents the average temperature of a gradient system well. Such a measurement system could, in principle, be used in conjunction with surface temperature measurement systems to monitor through-thickness temperature changes.
Text
s10921-023-01038-5
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More information
Accepted/In Press date: 6 December 2023
e-pub ahead of print date: 24 January 2024
Additional Information:
Funding Information: this work was supported by the Lloyds Register Foundation International Consortium of Nanotechnology, University of Southampton DTP fund, and the EPSRC under grant EP/S005463/1 (Better FITT Early detection of contact distress for enhanced performance monitoring and predictive inspection of machines).
Keywords:
Ultrasonic guided waves, Thermal barrier coatings, Temperature monitoring, Nozzle guide vanes
Identifiers
Local EPrints ID: 486519
URI: http://eprints.soton.ac.uk/id/eprint/486519
ISSN: 1573-4862
PURE UUID: 6ffddf37-fb25-4008-bf24-98d67c2e9f5b
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Date deposited: 25 Jan 2024 17:30
Last modified: 18 Mar 2024 04:10
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Contributors
Author:
Lawrence Yule
Author:
Nicholas Harris
Author:
Bahareh Zaghari
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