Design of next generation thermal barrier coatings — Experiments and modelling

Gupta, Mohit; Curry, Nicholas; Nylén, Per; Markocsan, Nicolaie; Vaßen, Robert

doi:10.1016/j.surfcoat.2012.09.015

Cited by 78 publications

(30 citation statements)

References 25 publications

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“…Convective heat transfer within the matrix to filler or pores is neglected because of convective heat transfer is significant only when pore size is large or if the gas pressure during operation is very high . The radiative heat transfer component is also neglected as it is significant only in higher temperatures range . In this section, the thermal conductivity of the composites has been estimated using OOF2 code.…”

Section: Resultsmentioning

confidence: 99%

“…It is seen that the heat flux varies in composites due to difference in thermal conductivities of materials as well as the presence of pores. The thermal conductivity of the composites ( κ c ) can be calculated as :

κ_{c} = \frac{Q_{avg}}{dT / dx}

where Q avg is the average heat energy flux per unit area, dT is the temperature difference and dx is the width of the microstructural image. A number of theoretical methods/models exist for the prediction of effective thermal conductivity of composites.…”

Section: Resultsmentioning

confidence: 99%

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Finite Element Analysis of the Microstructure of AlN–TiN Composites

Patel

Vaish

Sinha

et al. 2014

Strain

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Finite element modelling (FEM) is performed on AlN-TiN composites. The structure-property relationships are studied for 5 and 10 vol.% TiN composites in view of thermal and thermo-mechanical properties. Thermal stresses are simulated at various temperatures for the 5 and 10% TiN samples in homogeneous and heterogeneous temperature environments. It is found that compressive stresses are associated with the microstructure and these stresses are largest at the interface of the AlN-TiN phases. In addition, thermal strains are simulated at various temperatures for both the compositions. Thermal conductivity and thermal expansion coefficient are estimated using FEM and compared with other known analytical methods.

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Section: Resultsmentioning

confidence: 99%

κ_{c} = \frac{Q_{avg}}{dT / dx}

Section: Resultsmentioning

confidence: 99%

Finite Element Analysis of the Microstructure of AlN–TiN Composites

Patel

Vaish

Sinha

et al. 2014

Strain

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“…The internal convective cooling removes heat from the gas turbine blade, while the TBC provides a low thermal conductivity barrier that protects the blade against high-temperature oxidation, corrosion, and thermal cycling. 29 Figure 3 shows a one-dimensional system representing the wall of a convection-cooled gasturbine blade with a thermal barrier coating. Similar to the method used in Ref.…”

Section: Application To a System Of 1-d Models Representing The Hmentioning

confidence: 99%

A Purposed Model Coupling Framework for the Rapid Assembly of Complex System Simulations within an Integrated Computational Environment

McNunn

Bryden

2014

52nd Aerospace Sciences Meeting

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Often the emergent behavior of large-scale complex engineered and natural systems is a consequence of the interaction and interconnectivity between a large numbers of component subsystems. Consequently, modeling and simulating these large-scale systems requires methods that enable large numbers of heterogeneous, distributed models and databases to be assembled into a federated architecture that supports their interoperability and information sharing. However, to accurately propagate information through a federated system of models and databases a workflow is needed that identifies any data-related interdependencies that require an implicit solution and schedule the sequence of data exchanges, model runtimes, and database queries that is needed to evaluate the overall system. Although the local data exchanges that are needed to simulate the connectivity between any two components are often well understood, identifying the necessary workflow to solve a large-scale system of component models and databases is challenging and generally not practical using a hands-on or brute-force approach. As a result, a novel method is needed that identifies the computational workflow needed to accurately propagate data through a large-scale federated system of models and databases to ensure each component receives the necessary input data from the other components in the system prior to it being solved or queried. This paper develops a methodology that utilizes Tarjan's algorithm for finding the strongly connected components of a directed graph as a mechanism for organizing and scheduling the computational workflow needed to solve federated systems of models and databases based on the local input and output data associated with each component. The methodology is applied to identify the computational workflow needed to solve a system of models and databases representing the heat transfer and thermal stress in a one-dimensional gas turbine blade wall with a thermal barrier coating, and a system of models and databases representing a hybrid gas turbine, solid oxide fuel cell energy system.

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“…APS coatings can be tailored to a range of microstructural features to enable various operational behaviors and performances with distinct modulus, toughness, and conductivity properties. Common variants, including coatings with degrees of porosity and dense vertically cracked (DVC) coatings have allowed for an expansion of microstructurally linked, performance driven applications . Emerging of late is the application of multiple coating layers, tailored specifically to address disparate threats, including oxidation induced failure, erosion, and ash/sand particle damage, many of which occur simultaneously, engendering a need for multi‐functionality in performance …”

Section: Introductionmentioning

confidence: 99%

Orientation‐dependent mechanical and thermal properties of plasma‐sprayed ceramics

et al. 2018

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Due to droplet‐based assembly, microstructure anisotropy is expected in atmospheric plasma‐sprayed coatings (APS), with lamellar separations and interfaces having critical effects on properties. Quantitative determination of these anisotropic properties is difficult due to geometric test constraints. This has been overcome in the literature through a variety of indirect, local, or modeled evaluation, however direct measurement on like‐dimensioned coatings is not available. In this work, 25‐mm thick ceramic coating variants, deposited at two different feed rates, were obtained from industry and macroscopic mechanical and thermal properties were evaluated in both in‐plane and out‐of‐plane orientations using identical specimen geometries. As expected, and confirming select past work, coating anisotropy has a direct influence on measured properties. The response of each property is microstructure‐dependent, highlighting the specific interaction: for instance, the fracture toughness is 120% higher in the through‐thickness orientation versus in‐plane after thermal aging, while the thermal conductivity was 24% lower in the through‐thickness. The former benefits from the lamellar interfaces that provide obstacles to crack propagation while the latter sees these interfaces as efficient phonon scatters. The results provide insights for design through robust property measurements and into operational mechanisms in this class of highly defected ceramics.

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Design of next generation thermal barrier coatings — Experiments and modelling

Cited by 78 publications

References 25 publications

Finite Element Analysis of the Microstructure of AlN–TiN Composites

Finite Element Analysis of the Microstructure of AlN–TiN Composites

A Purposed Model Coupling Framework for the Rapid Assembly of Complex System Simulations within an Integrated Computational Environment

Orientation‐dependent mechanical and thermal properties of plasma‐sprayed ceramics

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