Determination of Thermal Barrier Coatings Average Surface Temperature After Engine Operation for Lifetime Validation

2012 ◽  
Vol 134 (12) ◽  
Author(s):  
Grégoire Witz ◽  
Hans-Peter Bossmann
Keyword(s):  
Surface Temperature ◽  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Operating Conditions ◽  
Thermal Barrier ◽  
Engine Operation ◽  
Barrier Coatings ◽  
Average Surface ◽  
Barrier Coating

Assessment of ex-service parts is important for the power generation industry. It gives us the opportunity to correlate part conditions to specific operating conditions like fuel used, local atmospheric conditions, operating regime, and temperature load. For assessment of thermal barrier coatings, one of the most valuable pieces of information is the local thermal condition. A method has been developed in Alstom, allowing determination of a thermal barrier coating average surface temperature after engine operation. It is based on the analysis of the phase composition of the thermal barrier coating by the acquisition of an X-ray diffraction spectrum of the coating surface, and its analysis using Rietveld refinement. The method has been validated by comparing its outcome to thermal models and base metal temperature mapping data. It is used for assessment of combustor and turbine coatings with various purposes: Determination of remnant coating life, building of lifing models, or determination of the coating degradation mechanisms under some specific operating conditions. Examples will be presented showing applications of this method.

Determination of Thermal Barrier Coatings Average Surface Temperature After Engine Operation for Lifetime Validation

2012 ◽  
Author(s):  
Grégoire Witz ◽  
Hans-Peter Bossmann
Keyword(s):  
Surface Temperature ◽  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Operating Conditions ◽  
Thermal Barrier ◽  
Engine Operation ◽  
Barrier Coatings ◽  
Average Surface ◽  
Barrier Coating

Assessment of ex-service parts is important for power generation industry. It gives the opportunity to correlate part conditions to specific operating conditions like fuel used, local atmospheric conditions, operating regime, and temperature load. For assessment of thermal barrier coatings, one of the most valuable information is the local thermal condition. A method has been developed in Alstom, allowing determination of a thermal barrier coating average surface temperature after engine operation. It is based on the analysis of the phase composition of the thermal barrier coating by the acquisition of an X-Ray diffraction spectrum of the coating surface, and its analysis using Rietveld refinement. The method has been validated by comparing its outcome to thermal models and base metal temperature mapping data. It is used for assessment of combustor and turbine coatings with various purposes: determination of remnant coating life, building of lifing models, or determination of the coating degradation mechanisms under some specific operating conditions. Examples will be presented showing applications of this method.

Field Evaluation of 2CaO-SiO2-CaO-ZrO2 Thermal Barrier Coating on Gas Turbine Vanes

1997 ◽  
Author(s):  
N. Mifune ◽  
Y. Harada ◽  
H. Taira ◽  
S. Mishima
Keyword(s):  
Gas Turbine ◽  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Field Evaluation ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Thermal Change ◽  
Barrier Coating ◽  
Turbine Vanes ◽  
Higher Temperature

Abstract Higher-temperature operation in a gas turbine has urged development of heat-resistant coatings and thermal barrier coatings. We have developed a 2CaO-SiO2-CaO-ZrO2 based thermal barrier coating. This coating should effectively prevent separation of the coating by relieving the shear stress generated due to thermal change of environment between layers with dissimilar properties. The coating was applied to stationary vanes of an actual gas turbine in a 25,000-hour test. This paper describes the results of the field test.

Effects of Powder Morphology, Microstructure, and Residual Stresses on Thermal Barrier Coating Thermal Shock Performance

1996 ◽  
Author(s):  
J. Wigren ◽  
J.-F. de Vries ◽  
D. Greving
Keyword(s):  
Residual Stresses ◽  
Thermal Shock ◽  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Gas Turbines ◽  
Thermal Barrier ◽  
Spray Parameters ◽  
Powder Morphology ◽  
Barrier Coatings ◽  
Barrier Coating

Abstract Thermal barrier coatings are used in the aerospace industry for thermal insulation in hot sections of gas turbines. Improved coating reliability is a common goal among jet engine designers. In-service failures, such as coating cracking and spallation, result in decreased engine performance and costly maintenance time. A research program was conducted to evaluate residual stresses, microstructure, and thermal shock life of thermal barrier coatings produced from different powder types and spray parameters. Sixteen coatings were ranked according to their performance relative to the other coatings in each evaluation category. Comparisons of residual stresses, powder morphology, and microstructure to thermal shock life indicate a strong correlation to thermal barrier coating performance. Results from these evaluations will aid in the selection of an optimum thermal barrier coating system for turbine engine applications.

Effect of Spinel Growth on the Delamination of Thermal Barrier Coatings

2011 ◽  
Vol 462-463 ◽  
pp. 389-394 ◽  
Author(s):  
Wei Xu Zhang ◽  
Yong Le Sun ◽  
Tie Jun Wang
Keyword(s):  
Growth Rate ◽  
Service Life ◽  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Unit Area ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Barrier Coating ◽  
Thermal Growth ◽  
Plasma Sprayed

The spinel growth induces undulation of the thermal growth oxide layer and decreases the service life of plasma-sprayed thermal barrier coatings. An analytical model is introduced to investigate the effect of spinel growth on the delamination of thermal barrier coating. The analytical results show that the number per unit area and the growth rate of spinel have significant influence on the delamination of thermal barrier coating. The stiffer and thicker thermal barrier coating is more easily to delaminate from the bond coat due to the existence of spinels. The effect of spinel on the delamination cannot be neglected. How to reduce the growth rate and the number of spinel is a key problem to prolong the service life of thermal barrier coatings.

A study of suspension plasma-sprayed insulated pistons evaluated in a heavy-duty diesel engine

2019 ◽  
Vol 21 (6) ◽  
pp. 987-997 ◽  
Author(s):  
Anders Thibblin ◽  
Ulf Olofsson
Keyword(s):  
Fuel Consumption ◽  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Heat Losses ◽  
Specific Fuel Consumption ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Barrier Coating ◽  
Plasma Sprayed

Thermal barrier coatings can be used to reduce the heat losses in heavy-duty diesel engines. A relatively new coating method for thermal barrier coatings is suspension plasma-spraying. Single-cylinder engine tests have been run to evaluate how heat losses to piston, cylinder head and exhausts as well as the specific fuel consumption are influenced by coating pistons with two different suspension plasma-sprayed thermal barrier coatings and one atmospheric plasma-sprayed thermal barrier coating, and comparing the results to those from an uncoated steel piston. The two suspension plasma-sprayed thermal barrier coatings showed reduced heat losses through the piston and less heat redirected to the cylinder head compared to conventional atmospheric plasma-sprayed thermal barrier coating, while one suspension plasma-sprayed coating with yttria-stabilized zirconia as top coat material showed increased exhaust temperature. However, the indicated specific fuel consumption was higher for all tested thermal barrier coatings than for an uncoated engine. The best performing thermal barrier coating with respect to indicated specific fuel consumption was a suspension plasma-sprayed coating with gadolinium zirconate as top coat material.

scholarly journals CFD/FEA Co-Simulation Framework for Analysis of the Thermal Barrier Coating Design and Its Impact on the HD Diesel Engine Performance

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2044
Author(s):  
Sean Moser ◽  
K. Dean Edwards ◽  
Tobias Schoeffler ◽  
Zoran Filipi
Keyword(s):  
Heat Flux ◽  
Boundary Conditions ◽  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Barrier Coating ◽  
Fea Modeling ◽  
Coating Design ◽  
Insight Into

Thermal barrier coatings (TBCs) have been investigated both experimentally and through simulation for mixing controlled combustion (MCC) concepts as a method for reducing heat transfer losses and increasing cycle efficiency, but it is still a very active research area. Early studies were inconclusive, with different groups discovering obstacles to realizing the theoretical potential. Nuanced papers have shown that coating material properties, thickness, microstructure, and surface morphology/roughness all can impact the efficacy of the thermal barrier coating and must be accounted for. Adding to the complexities, a strong spatial and temporal heat flux inhomogeneity exists for mixing controlled combustion (diesel) imposed onto the surfaces from the impinging flame jets. In support of the United States Department of Energy SuperTruck II program goal to achieve 55% brake thermal efficiency on a heavy-duty diesel engines, this study sought to develop a deeper insight into the inhomogeneous heat flux from mixing controlled combustion on thermal barrier coatings and to infer concrete guidance for designing coatings. To that end, a co-simulation approach was developed that couples high-fidelity computational fluid dynamics (CFD) modeling of in-cylinder processes and combustion, and finite element analysis (FEA) modeling of the thermal barrier-coated and metal engine components to resolve spatial and temporal thermal boundary conditions. The models interface at the surface of the combustion chamber; FEA modeling predicts the spatially resolved surface temperature profile, while CFD develops insights into the effect of the thermal barrier coating on the combustion process and the boundary conditions on the gas side. The paper demonstrates the capability of the framework to estimate cycle impacts of the temperature swing at the surface, as well as identify critical locations on the piston/thermal barrier coating that exhibit the highest charge temperature and highest heat fluxes. In addition, the FEA results include predictions of thermal stresses, thus enabling insight into factors affecting coating durability. An example of the capability of the framework is provided to illustrate its use for investigating novel coatings and provide deeper insights to guide future coating design.

Analysis of Conjugate Heat Transfer Between Cooling Film and Thermal Barrier Coatings Based on Micro-Structure

2016 ◽  
Author(s):  
Yuzhang Wang ◽  
Jiali Li ◽  
Hongzhao Liu ◽  
Yiwu Weng
Keyword(s):  
Heat Transfer ◽  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Conjugate Heat Transfer ◽  
Spatial Variations ◽  
Thermal Barrier ◽  
Micro Structure ◽  
Barrier Coatings ◽  
Barrier Coating ◽  
Micro Structures

Due to different preparation processes and long term operation, the micro structure of thermal barrier coating is different. The different micro structures have great effect on the thermal insulation properties of thermal barrier coatings and the conjugate heat transfer between the cooling film and thermal barrier coatings. In this work, different micro structures of thermal barrier coating were reconstructed using the scanning electron microscopy (SEM) images of two kinds of real thermal barrier coatings. The developed numerical calculation program based on the lattice Boltzmann method (LBM) was used to analyze the conjugate flow field and heat transfer between cooling film and porous thermal barrier coatings. The results show that the micro structures of thermal barrier coatings have a great influence on the stability of the surface film. Weak spatial variations in fluid velocity appear over the coating surface. The spatial variations in velocity over the layered coatings are larger because of its rough surfaces. The ratio of the vertical velocity to the bulk flow velocity can reach 2.5%. There is obvious vortex flow at the interface of coatings and cooling film, and weak flow in the interior perpendicular pores of the columnar coatings.

scholarly journals Stress and Displacement Distribution of the Thermal Barrier Coatings in the Turbine Engine Combustion Chamber

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 842
Author(s):  
Jianxin Wang ◽  
Zhenzhe Li ◽  
Fengxun Li
Keyword(s):  
Combustion Chamber ◽  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Operating Temperature ◽  
Turbine Blades ◽  
Thermally Grown Oxide ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Barrier Coating ◽  
Thermally Grown

A thermal barrier coating forms a high temperature resistant metal by the spraying of ceramics or other materials. Thermal barrier coatings are mainly used in the aviation field because they can significantly improve the thermal resistance of the aircraft engine turbine blades, combustion chamber and the other hot parts. In this paper, a thermal barrier coating model of the combustion chamber is established by using the finite element method. The stress field and displacement field of thermal barrier coatings under different thicknesses of the thermally grown oxide layer and thermal barrier coating layer, and the maximum operating temperature were studied. The results show that stress and deformation under the three thermal cycles increase with the increase in operating temperature and the thickness of thermally grown oxide (TGO) and thermal barrier coat (TBC), except for the case of TGO thickness of 2 μm.

Depletion Model of Aluminum in Bond Coat for Plasma-Sprayed Thermal Barrier Coatings

2009 ◽  
Vol 75 ◽  
pp. 31-35 ◽  
Author(s):  
Chang Che ◽  
G.Q. Wu ◽  
Hong Yu Qi ◽  
Z. Huang ◽  
Xiao Guang Yang
Keyword(s):  
Mathematical Model ◽  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Bond Coat ◽  
Thermal Exposure ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Barrier Coatings ◽  
Barrier Coating ◽  
Plasma Sprayed

The aluminum depletion of NiCrAlY bond coat in an air-plasma-sprayed thermal barrier coating (TBC) has been studied by experimental and simulative approaches. Upon thermal exposure, Al depletion regions were observed. The depletion of aluminum is resulting from Al diffusion towards the surface of bond coat and into substrate. A mathematical model of Al depletion was presented. The model is able to explain the observed results in a qualitative way and has been shown that Al depletes within the bond coat by diffusion.

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