Analysis of thermal radiation effects on temperatures in turbine engine thermal barrier coatings

Siegel, Robert; Spuckler, C. M.

doi:10.1016/s0921-5093(97)00845-9

Cited by 121 publications

(67 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The value [57] of n for PS YSZ, in the wavelength range of interest, is ~2.1. Radiative heat transport is in general the outcome of multiple scattering and absorption events, as well as direct radiative transfer.…”

Section: Radiative Heat Transfermentioning

confidence: 94%

“…Fine columnar grains form during solidification, aligned normal to the plane of the coating. There has also been study [57][58][59] of radiation transmission characteristics. The material is relatively transparent to wavelengths in the near infra-red, although this radiation is strongly scattered by interfaces and grain boundaries.…”

Section: Composition and Microstructurementioning

confidence: 99%

See 1 more Smart Citation

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

2009

View full text Add to dashboard Cite

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 (ie 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 modelling 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.

show abstract

Section: Radiative Heat Transfermentioning

confidence: 94%

Section: Composition and Microstructurementioning

confidence: 99%

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

2009

View full text Add to dashboard Cite

show abstract

“…Unfortunately, this radiation part cannot be extracted from the radiation correction of the LFA measurement This requires a detailed analyses of the influence of radiation, translucency and emissivity of TBCs that can be found e.g. in [21,22]. An additional effect that needs to be considered when measuring k is the atmosphere.…”

Section: Methodsmentioning

confidence: 99%

Thermal conductivity issues of EB‐PVD thermal barrier coatings

Schulz¹,

Rätzer‐Scheibe

Saruhan

et al. 2007

Materialwissenschaft Werkst

View full text Add to dashboard Cite

The thermal conductivity of electron-beam physical vapor deposited (EB-PVD) thermal barrier coatings (TBCs) was investigated by the Laser Flash technique. Sample type and methodology of data analyses as well as atmosphere during the measurement have some influence on the data. A large variation of the thermal conductivity was found by changes in TBC microstructure. Exposure at high temperature caused sintering of the porous microstructure that finally increased thermal conductivity up to 30 %. EB-PVD TBCs show a distinct thickness dependence of the thermal conductivity due to the anisotropic microstructure in thickness direction. Thin TBCs had a 20 % lower thermal conductivity than thick coatings.

show abstract

“…Fine columnar grains form during solidification, aligned normal to the plane of the coating. There has also been study (Siegel & Spuckler 1998;Petrov & Chernyshev 1999;Eldridge et al 2002) of radiation transmission characteristics. The material is relatively transparent to wavelengths in the near infrared part of the spectrum, although this radiation can be scattered by interfaces and grain boundaries.…”

Section: Illustrative Case Historiesmentioning

confidence: 99%

Porous materials for thermal management under extreme conditions

Clyne

Golosnoy

Tan

et al. 2005

Phil. Trans. R. Soc. A.

116

View full text Add to dashboard Cite

A brief analysis is presented of how heat transfer takes place in porous materials of various types. The emphasis is on materials able to withstand extremes of temperature, gas pressure, irradiation, etc., i.e. metals and ceramics, rather than polymers. A primary aim is commonly to maximize either the thermal resistance (i.e. provide insulation) or the rate of thermal equilibration between the material and a fluid passing through it (i.e. to facilitate heat exchange). The main structural characteristics concern porosity (void content), anisotropy, pore connectivity and scale. The effect of scale is complex, since the permeability decreases as the structure is refined, but the interfacial area for fluid-solid heat exchange is, thereby, raised. The durability of the pore structure may also be an issue, with a possible disadvantage of finer scale structures being poor microstructural stability under service conditions. Finally, good mechanical properties may be required, since the development of thermal gradients, high fluid fluxes, etc. can generate substantial levels of stress. There are, thus, some complex interplays between service conditions, pore architecture/scale, fluid permeation characteristics, convective heat flow, thermal conduction and radiative heat transfer. Such interplays are illustrated with reference to three examples: (i) a thermal barrier coating in a gas turbine engine; (ii) a Space Shuttle tile; and (iii) a Stirling engine heat exchanger. Highly porous, permeable materials are often made by bonding fibres together into a network structure and much of the analysis presented here is oriented towards such materials.

show abstract

Analysis of thermal radiation effects on temperatures in turbine engine thermal barrier coatings

Cited by 121 publications

References 13 publications

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

Thermal conductivity issues of EB‐PVD thermal barrier coatings

Porous materials for thermal management under extreme conditions

Contact Info

Product

Resources

About