THE EFFECT OF THERMAL BARRIER COATING SURFACE TEMPERATURE ON THE ADHESION BEHAVIOR OF CMAS DEPOSITS

2021 ◽  
pp. 1-14
Author(s):  
Robert A. Clark ◽  
Nicholas Plewacki ◽  
Pritheesh Gnanaselvam ◽  
Jeffrey P. Bons ◽  
Vaishak Viswanathan
Keyword(s):  
High Pressure ◽  
Surface Temperature ◽  
Thermal Barrier Coating ◽  
Thermal Barrier ◽  
Back Side ◽  
Gas Temperature ◽  
Front Side ◽  
Barrier Coating ◽  
Inlet Conditions ◽  
Side Flow

Abstract The interaction of thermal barrier coating’s (TBC) surface temperature with CMAS (calcium magnesium aluminosilicate) like deposits in gas turbine hot flowpath hardware is investigated. Small Hastelloy X coupons were coated in TBC and then subjected to a thermal gradient via back-side impingement cooling and front-side impingement heating using the High Temperature Deposition Facility (HTDF) at The Ohio State University (OSU). TBC front-side surface temperatures were varied by changing a constant temperature back-side mass flow, while maintaining a constant hot-side gas temperature and jet velocity representative of modern commercial turbofan high-pressure turbine (HPT) inlet conditions (approximately 1600K and 200 m/s, or Mach 0.25). In this study, Arizona Road Dust (ARD) was utilized to mimic the behavior of CMAS attack on TBCs. Accelerated deposition tests were performed where approximately 1 gram of ARD was injected into the hot side flow while the TBC surface temperature was held at various points above the minimum observed deposition temperature. Surface deposition on the TBC coupons was evaluated using an infrared camera and a backside thermocouple. In addition, an Eulerian-Lagrangian solver was used to model the hot-side impinging jet AND deposition was predicted using the OSU Deposition model. These results can be used to improve physics-based deposition models by providing valuable data relative to CMAS deposition characteristics on TBC surfaces, which modern commercial turbofan high pressure turbines use almost exclusively.

The Effect of Thermal Barrier Coating Surface Temperature on the Adhesion Behavior of CMAS Deposits

2020 ◽  
Author(s):  
Robert A. Clark ◽  
Nicholas Plewacki ◽  
Pritheesh Gnanaselvam ◽  
Jeffrey P. Bons ◽  
Vaishak Viswanathan
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Surface Temperature ◽  
Mass Flow ◽  
Experimental Results ◽  
Thermal Barrier ◽  
Back Side ◽  
Surface Temperatures ◽  
The Impact ◽  
Side Flow

Abstract The interaction of thermal barrier coating’s surface temperature with CMAS (calcium magnesium aluminosilicate) like deposits in gas turbine hot flowpath hardware is investigated. Small Hastelloy X coupons were coated in TBC using the air plasma spray (APS) method and then subjected to a thermal gradient via back-side impingement cooling and front-side impingement heating using the High Temperature Deposition Facility (HTDF) at The Ohio State University (OSU). A 1-D heat transfer model was used to estimate TBC surface temperatures and correlate them to intensity values taken from infrared (IR) images of the TBC surface. TBC frontside surface temperatures were varied by changing back-side mass flow (kept at a constant temperature), while maintaining a constant hot-side gas temperature and jet velocity representative of modern commercial turbofan high-pressure turbine (HPT) inlet conditions (approximately 1600K and 200 m/s, or Mach 0.25). In this study, Arizona Road Dust (ARD) was utilized to mimic the behavior of CMAS attack on TBCs. To identify the minimum temperature at which particles adhere, the back-side cooling mass flow was set to the maximum amount allowed by the test setup, and trace amounts of 0–10 μm ARD particles were injected into the hot-side flow to impinge on the TBC surface. The TBC surface temperature was increased through coolant reduction until noticeable deposits formed, as evaluated through an IR camera. Accelerated deposition tests were then performed where approximately 1 gram of ARD was injected into the hot side flow while the TBC surface temperature was held at various points above the minimum observed deposition temperature. Surface deposition on the TBC coupons was evaluated using an infrared camera and a backside thermocouple. Coupon cross sections were also evaluated under a scanning electron microscope for any potential CMAS ingress into the TBC. Experimental results of the impact of surface temperature on CMAS deposition and deposit evolution and morphology are presented. In addition, an Eulerian-Lagrangian solver was used to model the hot-side impinging jet with particles at four TBC surface temperatures and deposition was predicted using the OSU Deposition model. Comparisons to experimental results highlight the need for more sophisticated modeling of deposit development through conjugate heat transfer and mesh morphing of the target surface. These results can be used to improve physics-based deposition models by providing valuable data relative to CMAS deposition characteristics on TBC surfaces, which modern commercial turbofan high pressure turbines use almost exclusively.

Results From the Phase II Test Using the High-Temperature Developing Unit (HTDU)

1988 ◽  
Vol 110 (2) ◽  
pp. 251-258 ◽  
Author(s):  
S. Aoki ◽  
K. Teshima ◽  
M. Arai ◽  
H. Yamao
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Thermal Barrier Coating ◽  
Phase Ii ◽  
Thermal Barrier ◽  
Test Results ◽  
High Pressure Turbine ◽  
Barrier Coating ◽  
Two Stages

Phase II of the high-temperature turbine test was performed using the High-Temperature Developing Unit (HTDU). This unit has the same two stages as the high-pressure turbine of the AGTJ-100A reheat system. The purpose of the Phase II test was to investigate the potential of candidate technologies that may be applied to the advanced engine, the AGTJ-100B. Cooling characteristics of several cooling schemes for the first stage blades, and the performance of thermal barrier coating employed on the first stage nozzles and blades, were investigated. This paper presents the Phase II test results.

The Effect of Thermal Barrier Coating Surface Temperature on the Adhesion Behavior of CMAS Deposits

2021 ◽  
Author(s):  
Robert Clark ◽  
Nicholas Plewacki ◽  
Pritheesh Gnanaselvam ◽  
Jeffrey Bons ◽  
Vaishak Viswanathan
Keyword(s):  
Surface Temperature ◽  
Thermal Barrier Coating ◽  
Thermal Barrier ◽  
Coating Surface ◽  
Barrier Coating ◽  
Adhesion Behavior

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.

Estimation of Thermal Barrier Coating Surface Temperature and Heat Flux Profiles in a Low Temperature Combustion Engine Using a Modified Sequential Function Specification Approach

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Ryan N. O'Donnell ◽  
Thomas R. Powell ◽  
Zoran S. Filipi ◽  
Mark A. Hoffman
Keyword(s):  
Heat Flux ◽  
Surface Temperature ◽  
Thermal Barrier Coating ◽  
Combustion Engine ◽  
Ex Situ ◽  
Multiple Time Scales ◽  
Thermal Barrier ◽  
Coating Surface ◽  
Barrier Coating ◽  
Sequential Function Specification

A modified form of the sequential function specification method (SFSM) is developed with specific consideration given to multiple time scales in an effort to avoid overregularization of the solution estimates. The authors extend their approach to solve the inverse heat conduction problem (IHCP) associated with the application of thermal barrier coatings (TBC) to in-cylinder surfaces of an internal combustion engine. Subsurface temperature measurements are used to calculate surface heat flux profiles. The modified inverse solver is validated ex situ using a custom fabricated radiation chamber. The solution methodology is extended in situ to evaluate temperature data collected from a single-cylinder research engine operating in homogeneous charge compression ignition (HCCI) mode. Crank angle resolved, thermal barrier coating surface temperature and heat flux profiles are produced—enabling correlation of thermal conditions at the gas-wall boundary with engine performance, emission, and efficiency metrics.

Determination of Cooling Parameters for a High-Speed, True-Scale, Metallic Turbine Vane

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Marc D. Polanka ◽  
James L. Rutledge ◽  
David G. Bogard ◽  
Richard J. Anthony
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Low Temperature ◽  
Surface Temperature ◽  
Thermal Barrier Coating ◽  
Biot Number ◽  
Operating Conditions ◽  
Thermal Barrier ◽  
Barrier Coating ◽  
Overall Effectiveness

Facilities such as the Turbine Research Facility (TRF) at the Air Force Research Laboratory have been acquiring uncooled heat transfer measurements on full-scale metallic airfoils for several years. The addition of cooling flow to this type of facility has provided new capabilities and new challenges. Two primary challenges for cooled rotating hardware are that the true local film temperature is unknown, and cooled thin-walled metallic airfoils prohibit semi-infinite heat conduction calculation. Extracting true local adiabatic effectiveness and the heat transfer coefficient from measurements of surface temperature and surface heat transfer is therefore difficult. In contrast, another cooling parameter, the overall effectiveness (ϕ), is readily obtained from the measurements of surface temperature, internal coolant temperature, and mainstream temperature. The overall effectiveness is a normalized measure of surface temperatures expected for actual operating conditions and is thus an important parameter that drives the life expectancy of a turbine component. Another issue is that scaling ϕ from experimental conditions to engine conditions is dependent on the heat transfer through the part. It has been well-established that the Biot number must be matched for the experimentally measured ϕ to match ϕ at engine conditions. However, the thermal conductivity of both the metal blade and the thermal barrier coating changes substantially from low-temperature to high-temperature engine conditions and usually not in the same proportion. This paper describes a novel method of replicating the correct thermal behavior of the thermal barrier coating (TBC) relative to the metal turbine while obtaining surface temperature measurements and heat fluxes. Furthermore, this paper describes how the ϕ value obtained at the low-temperature conditions can be adjusted to predict ϕ at high-temperature engine conditions when it is impossible to match the Biot number perfectly.

Uncertainty Quantification and Conjugate Heat Transfer: A Stochastic Analysis

2012 ◽  
Author(s):  
F. Montomoli ◽  
A. D’Ammaro ◽  
S. Uchida
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Uncertainty Quantification ◽  
Thermal Barrier Coating ◽  
Coating Thickness ◽  
Conjugate Heat Transfer ◽  
Metal Temperature ◽  
Thermal Barrier ◽  
Barrier Coating ◽  
Pressure Nozzle

Conjugate Heat Transfer studies are a common method to predict the thermal loading in high pressure nozzles. Despite the accuracy of nowadays tools, it is not clear how to include the uncertainties associated to the turbulence level, the temperature distribution or the thermal barrier coating thickness in the numerical simulations. All these parameters are stochastic even if their value is commonly assumed to be deterministic. For the first time, in this work a stochastic analysis is used to predict the metal temperature in a real high pressure nozzle. The domain is the complete high pressure nozzle of F-type Mitsubishi Heavy Industries gas turbine with impingement, film and trailing edge cooling. The stochastic variations are included by coupling Uncertainty Quantification Methods and Conjugate Heat Transfer. Two Uncertainty Quantification methods have been compared: a Probabilistic Collocation Method (PCM) and a Stochastic Collocation Method (SCM). The stochastic distribution of thermal barrier coating thickness, used in the simulations, has been measured at the midspan. A Gaussian distribution for the turbulence intensity and hot core location has been assumed. By using PCM and SCM, the probability to obtain specific metal temperature at midspan is evaluated. The two methods predict the same distribution of temperature with a maximum difference of 0.6% and the results are compared with the experimental data measured in the real engine. The experimental data are inside the uncertainty band associated to the CFD predictions except near at the trailing edge on the pressure side. This work shows that one of the most important parameters affecting the metal temperature uncertainty is the pitch-wise location of the hot core. Assuming a probability distribution for this location, with a standard deviation of 1.7 degrees, the metal temperature at midspan can change up to 30%. The impact of turbulence level and thermal barrier coating thickness is one order of magnitude less important.

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.

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