Thermal-Mechanical Effects of Ceramic Thermal Barrier Coatings on Diesel Engine Piston

2001 ◽  
Vol 697 ◽  
Author(s):  
Jesse G. Muchai ◽  
Ajit D. Kelkar ◽  
David E. Klett ◽  
Jagannathan Sankar
Keyword(s):  
Diesel Engine ◽  
Thermal Barrier Coatings ◽  
Coating Thickness ◽  
High Stress ◽  
Thermal Barrier ◽  
Element Analysis ◽  
Simulation Code ◽  
Barrier Coatings ◽  
Thermal Boundary Conditions ◽  
Cycle Simulation

AbstractThe purpose of this paper is to investigate the piston temperature and stress distribution resulting from varying coating thicknesses of Partially Stabilized Zirconia (PSZ) thermal barrier coatings for the performance in diesel engine applications. This analysis is based on the premise that coating thickness affects the heat transfer and temperature distribution in the piston. A gas dynamic engine cycle simulation code was used to obtain thermal boundary conditions on the piston then, a 2-D axisymmetric Finite Element Analysis (FEA) using ANSYS was performed to evaluate the temperature and stress distributions in the piston as a function of coating thickness. Coating thicknesses studied include 0.1, 0.2, 0.3, 0.5, 1.0, 1.5, and 2.0mm. The results indicate increased piston surface temperature with increasing coating thickness. The maximum stress on the coated piston surface was high while the substrate stress was less than the coating yield stress for all coating thicknesses. Further, the analysis showed that the interface stress at all coated conditions is low enough such that no separation of the coating is expected. The FEA results suggest an optimum coating thickness of 0.1 to 1.5 mm for diesel engine application to avoid unduly high stress in the ceramic.

High Temperature Radiation Heat Transfer Performance of Thermal Barrier Coatings With Multiple Layered Structures

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Xiao Huang
Keyword(s):  
Heat Transfer ◽  
Thermal Radiation ◽  
Thermal Barrier Coatings ◽  
Wavelength Range ◽  
Coating Thickness ◽  
Single Layer ◽  
Layered Structures ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Layered Coating

Meeting the demands for ever increasing operating temperatures in gas turbines requires concurrent development in cooling technologies, new generations of superalloys, and thermal barrier coatings (TBCs) with increased insulation capability. In the case of the latter, considerable research continues to focus on new coating material compositions, the alloying/doping of existing yttria stabilized zirconia ceramics, and the development of improved coating microstructures. The advent of the electron beam physical vapor deposition coating process has made it possible to consider the creation of multiple layered coating structures to meet specific performance requirements. In this paper, the advantages of layered structures are first reviewed in terms of their functions in impeding thermal conduction (via phonons) and thermal radiation (via photons). Subsequently, the design and performance of new multiple layered coating structures based on multiple layered stacks will be detailed. Designed with the primary objective to reduce thermal radiation transport through TBC systems, the multiple layered structures consist of several highly reflective multiple layered stacks, with each stack used to reflect a targeted radiation wavelength range. Two ceramic materials with alternating high and low refractive indices are used in the stacks to provide multiple-beam interference. A broadband reflection of the required wavelength range is obtained using a sufficient number of stacks. In order to achieve an 80% reflectance to thermal radiation in the wavelength range 0.3–5.3μm, 12 stacks, each containing 12 layers, are needed, resulting in a total thickness of 44.9μm. Using a one dimensional heat transfer model, the steady state heat transfer through the multiple layered TBC system is computed. Various coating configurations combining multiple layered stacks along with a single layer are evaluated in terms of the temperature profile in the TBC system. When compared with a base line single layered coating structure of the same thickness, it is estimated that the temperature on the metal surface can be reduced by as much as 90°C due to the use of multiple layered coating configurations. This reduction in metal surface temperature, however, diminishes with increasing the scattering coefficient of the coating and the total coating thickness. It is also apparent that using a multiple layered structure throughout the coating thickness may not offer the best thermal insulation; rather, placing multiple layered stacks on top of a single layer can provide a more efficient approach to reducing the heat transport of the TBC system.

High Temperature Radiation Heat Transfer Performance of Thermal Barrier Coatings With Multiple Layered Structures

2008 ◽  
Author(s):  
Xiao Huang
Keyword(s):  
Heat Transfer ◽  
Thermal Radiation ◽  
Thermal Barrier Coatings ◽  
Wavelength Range ◽  
Coating Thickness ◽  
Single Layer ◽  
Layered Structures ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Layered Coating

Meeting the demands for ever increasing operating temperatures in gas turbines requires concurrent development in cooling technologies, new generations of superalloys, and thermal barrier coatings (TBCs) with increased insulation capability. In the case of the latter, considerable research continues to focus on new coating material compositions, alloying/doping existing yttria stabilized zirconia ceramics, and the development of improved coating microstructures. The advent of the EB-PVD coating process has made it possible to consider the creation of multiple layered coating structures to meet specific performance requirements. In this paper, the advantages of layered structures are first reviewed in terms of their functions in impeding thermal conduction (via phonons) and thermal radiation (via photons). Subsequently, the design and performance of new multiple layered coating structures based on multiple layered stacks will be detailed. Designed with the primary objective to reduce thermal radiation transport through TBC systems, the multiple layered structures consist of several highly reflective multiple layered stacks, with each stack used to reflect a targeted radiation wavelength range. Two ceramic materials with alternating high and low refractive indices are used in the stacks to provide multiple-beam interference. A broadband reflection of the required wavelength range is obtained using a sufficient number of stacks. In order to achieve 80% reflectance to thermal radiation in the wavelength range of 0.3 ∼ 5.3 μm, 12 stacks, each containing 12 layers, are needed, resulting in a total thickness of 44.9 μm. Using a one dimensional heat transfer model, steady state heat transfer through the multiple layered TBC system is computed. Various coating configurations combining multiple layered stacks along with a single layer are evaluated in terms of the temperature profile in the TBC system. When compared to a baseline single layered coating structure of the same thickness, it is estimated that the temperature on the metal surface can be reduced by as much as 90°C due to the use of multiple layered coating configurations. This reduction in metal surface temperature, however, diminishes with increasing scattering coefficient of the coating and total coating thickness. It is also apparent that using a multiple layered structure throughout the coating thickness may not offer the best thermal insulation; rather, placing multiple layered stacks on top of a single layer can provide a more efficient approach to reduce the heat transport of the TBC system.

Running-in behaviour of thermal barrier coatings in the combustion chamber of a diesel engine

2019 ◽  
Vol 234 (1) ◽  
pp. 172-182 ◽  
Author(s):  
Anders Thibblin ◽  
Siamak Kianzad ◽  
Stefan Jonsson ◽  
Ulf Olofsson
Keyword(s):  
Heat Flux ◽  
Diesel Engine ◽  
Thermal Barrier Coatings ◽  
Yttria Stabilized Zirconia ◽  
Thermal Barrier ◽  
Heavy Duty ◽  
Stabilized Zirconia ◽  
Barrier Coatings ◽  
Heavy Duty Diesel

Thermal barrier coatings have the potential to improve the fuel efficiency of heavy-duty diesel engines by reducing heat losses. A method for in-situ measurement of heat flux from the combustion chamber of a heavy-duty diesel engine has been developed and was used to study the running-in behaviour of different thermal barrier coating materials and types of microstructures. The in-situ measurements show that the initial heat flux was reduced by up to 4.7% for all investigated thermal barrier coatings compared to a steel reference, except for an yttria-stabilized zirconia coating with sealed pores that had an increase of 12.0% in heat flux. Gd2Zr2O7 had the lowest initial value for heat flux. However, running-in shows the lowest values for yttria-stabilized zirconia after 2–3 h. Potential spallation problems were observed for Gd2Zr2O7 and La2Zr2O7.

Comprehensive Numerical Simulation of Stress and Damage Fields under Thermo-Mechanical Loading for TBC-Coated Ni-Based Superalloy

2018 ◽  
Vol 774 ◽  
pp. 137-142 ◽  
Author(s):  
Hiroaki Katori ◽  
Masayuki Arai ◽  
Kiyohiro Ito
Keyword(s):  
Numerical Simulation ◽  
Constitutive Equation ◽  
Thermal Barrier Coatings ◽  
Peak Stress ◽  
Thermal Barrier ◽  
High Temperature Creep ◽  
Wave Loading ◽  
Element Analysis ◽  
Barrier Coatings ◽  
Start Up

A finite element analysis code was developed to accurately predict stress and damage fields in thermal barrier coatings (TBCs) systems subjected to thermo-mechanical loadings. An inelastic constitutive equation for TBCs, and a Chaboche-type viscoplastic constitutive equation for Ni-based super alloys (IN738LC) were employed to simulate high temperature creep and cyclic deformation. Simulations of the TBC/IN738LC system subjected to two types of loading, namely, a triangle-wave loading and a GT-operation loading, were performed using the developed analysis code. The results confirmed that the stress and damage fields in the TBC/IN738LC system could be simulated accurately, and provided us with credible results regarding the crack occurrence. Additionally, the analysis under the GT-operation loading conditions revealed that a peak stress generated during the start-up operation would lead to delamination of the TBC, while a peak stress at the shut-down would lead to cracking in the substrate.

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