The University of Southampton
University of Southampton Institutional Repository

Heat Transfer Through Plasma-Sprayed Thermal Barrier Coatings in Gas Turbines: A Review of Recent Work

Heat Transfer Through Plasma-Sprayed Thermal Barrier Coatings in Gas Turbines: A Review of Recent Work
Heat Transfer Through Plasma-Sprayed Thermal Barrier Coatings in Gas Turbines: A Review of Recent Work
A review is presented of how heat transfer takes place in plasma-sprayed (zirconia-based) thermal barrier coatings (TBCs) during operation of gas turbines. These characteristics of TBCs are naturally of central importance to their function. Current state-of-the-art TBCs have relatively high levels of porosity (~15%) and the pore architecture (i.e., its morphology, connectivity, and scale) has a strong influence on the heat flow. Contributions from convective, conductive, and radiative heat transfer are considered, under a range of operating conditions, and the characteristics are illustrated with experimental data and modeling predictions. In fact, convective heat flow within TBCs usually makes a negligible contribution to the overall heat transfer through the coating, although what might be described as convection can be important if there are gross through-thickness defects such as segmentation cracks. Radiative heat transfer, on the other hand, can be significant within TBCs, depending on temperature and radiation scattering lengths, which in turn are sensitive to the grain structure and the pore architecture. Under most conditions of current interest, conductive heat transfer is largely predominant. However, it is not only conduction through solid ceramic that is important. Depending on the pore architecture, conduction through gas in the pores can play a significant role, particularly at the high gas pressures typically acting in gas turbines (although rarely applied in laboratory measurements of conductivity). The durability of the pore structure under service conditions is also of importance, and this review covers some recent work on how the pore architecture, and hence the conductivity, is affected by sintering phenomena. Some information is presented concerning the areas in which research and development work needs to be focussed if improvements in coating performance are to be achieved.
plasma spray coatings, pore connectivity, sintering, thermal barrier coatings, thermal conductivity, zironia
1059-9630
809-821
Golosnoy, I.O.
40603f91-7488-49ea-830f-24dd930573d1
Cipitria, A.
53f2ee50-b925-41f3-a195-ecb46fce2c01
Clyne, T.W.
00678bf7-17de-46e8-9b35-bf1ca73bce9b
Golosnoy, I.O.
40603f91-7488-49ea-830f-24dd930573d1
Cipitria, A.
53f2ee50-b925-41f3-a195-ecb46fce2c01
Clyne, T.W.
00678bf7-17de-46e8-9b35-bf1ca73bce9b

Golosnoy, I.O., Cipitria, A. and Clyne, T.W. (2009) Heat Transfer Through Plasma-Sprayed Thermal Barrier Coatings in Gas Turbines: A Review of Recent Work. Journal of Thermal Spray Technology, 18 (5-6), 809-821. (doi:10.1007/s11666-009-9337-y).

Record type: Article

Abstract

A review is presented of how heat transfer takes place in plasma-sprayed (zirconia-based) thermal barrier coatings (TBCs) during operation of gas turbines. These characteristics of TBCs are naturally of central importance to their function. Current state-of-the-art TBCs have relatively high levels of porosity (~15%) and the pore architecture (i.e., its morphology, connectivity, and scale) has a strong influence on the heat flow. Contributions from convective, conductive, and radiative heat transfer are considered, under a range of operating conditions, and the characteristics are illustrated with experimental data and modeling predictions. In fact, convective heat flow within TBCs usually makes a negligible contribution to the overall heat transfer through the coating, although what might be described as convection can be important if there are gross through-thickness defects such as segmentation cracks. Radiative heat transfer, on the other hand, can be significant within TBCs, depending on temperature and radiation scattering lengths, which in turn are sensitive to the grain structure and the pore architecture. Under most conditions of current interest, conductive heat transfer is largely predominant. However, it is not only conduction through solid ceramic that is important. Depending on the pore architecture, conduction through gas in the pores can play a significant role, particularly at the high gas pressures typically acting in gas turbines (although rarely applied in laboratory measurements of conductivity). The durability of the pore structure under service conditions is also of importance, and this review covers some recent work on how the pore architecture, and hence the conductivity, is affected by sintering phenomena. Some information is presented concerning the areas in which research and development work needs to be focussed if improvements in coating performance are to be achieved.

Text
IOG_et_al_review_JTST.pdf - Accepted Manuscript
Download (1MB)

More information

Published date: 15 December 2009
Keywords: plasma spray coatings, pore connectivity, sintering, thermal barrier coatings, thermal conductivity, zironia
Organisations: EEE

Identifiers

Local EPrints ID: 267635
URI: http://eprints.soton.ac.uk/id/eprint/267635
ISSN: 1059-9630
PURE UUID: 8bb89dbe-7f6b-4def-a2b7-02a22edcfc73

Catalogue record

Date deposited: 29 Jun 2009 14:48
Last modified: 16 Dec 2019 20:41

Export record

Altmetrics

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×