Conjugate flow and heat transfer analysis between segmented thermal barrier coatings and cooling film

2021 ◽  
Vol 167 ◽  
pp. 107003
Author(s):  
Yun Long ◽  
Xiaohu Chen ◽  
Yuzhang Wang ◽  
Yiwu Weng
Keyword(s):  
Heat Transfer ◽  
Thermal Barrier Coatings ◽  
Heat Transfer Analysis ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Flow And Heat Transfer

Performance and Steady State Heat Transfer Analysis of Functionally Graded Thermal Barrier Coatings Systems

2018 ◽  
Vol 5 (14) ◽  
pp. 27936-27945 ◽  
Author(s):  
Kirti Teja Pasupuleti ◽  
Shawn Dsouza ◽  
R. Thejaraju ◽  
Shankar Venkataraman ◽  
Parvati Ramaswamy ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Thermal Barrier Coatings ◽  
Functionally Graded ◽  
Heat Transfer Analysis ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
State Heat ◽  
Steady State Heat ◽  
Steady State Heat Transfer

Microstructure and Heat Transfer Phenomena in Ceramic Thermal Barrier Coatings

2001 ◽  
Vol 84 (4) ◽  
pp. 827-835 ◽  
Author(s):  
Paolo Scardi ◽  
Matteo Leoni ◽  
Federico Cernuschi ◽  
Angelamaria Figari
Keyword(s):  
Heat Transfer ◽  
Thermal Barrier Coatings ◽  
Thermal Barrier ◽  
Barrier Coatings

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.

scholarly journals Analysis of the energetic/environmental performances of gas turbine plant: Effect of thermal barrier coatings and mass of cooling air

2009 ◽  
Vol 13 (1) ◽  
pp. 147-164 ◽  
Author(s):  
Ion Ion ◽  
Anibal Portinha ◽  
Jorge Martins ◽  
Vasco Teixeira ◽  
Joaquim Carneiro
Keyword(s):  
Thermal Conductivity ◽  
Gas Turbine ◽  
Thermal Barrier Coatings ◽  
Turbine Blades ◽  
Heat Transfer Analysis ◽  
Thermal Barrier ◽  
Inlet Temperature ◽  
Barrier Coatings ◽  
Cooling Air Flow ◽  
Cooling Air

Zirconia stabilized with 8 wt.% Y2O3 is the most common material to be applied in thermal barrier coatings owing to its excellent properties: low thermal conductivity, high toughness and thermal expansion coefficient as ceramic material. Calculation has been made to evaluate the gains of thermal barrier coatings applied on gas turbine blades. The study considers a top ceramic coating Zirconia stabilized with 8 wt.% Y2O3 on a NiCoCrAlY bond coat and Inconel 738LC as substrate. For different thickness and different cooling air flow rates, a thermodynamic analysis has been performed and pollutants emissions (CO, NOx) have been estimated to analyze the effect of rising the gas inlet temperature. The effect of thickness and thermal conductivity of top coating and the mass flow rate of cooling air have been analyzed. The model for heat transfer analysis gives the temperature reduction through the wall blade for the considered conditions and the results presented in this contribution are restricted to a two considered limits: (1) maximum allowable temperature for top layer (1200?C) and (2) for blade material (1000?C). The model can be used to analyze other materials that support higher temperatures helping in the development of new materials for thermal barrier coatings.

A Conjugate 3-D Flow and Heat Transfer Analysis of a Thermal Barrier Cooled Turbine Guide Vane

1998 ◽  
Author(s):  
Dieter E. Bohn ◽  
Volker J. Becker
Keyword(s):  
Heat Transfer ◽  
Gas Turbines ◽  
Guide Vane ◽  
Suction Side ◽  
Heat Transfer Analysis ◽  
Thermal Barrier ◽  
Trailing Edge ◽  
Flow And Heat Transfer ◽  
Turbine Guide Vane ◽  
Basic Configuration

This paper presents the numerical investigations of the flow and heat transfer of two configurations of a transonic turbine guide vane. The basic configuration is a vane with convection cooling. The second configuration is additionally coated with a thermal barrier consisting of ZrO2. The results are obtained with a conjugate heat transfer and flow computer code that has been developed at the Institute of Steam and Gas Turbines. Measurement data is available for the basic configuration and the computational results are compared to the experimental results. The results show very good agreement between calculated and measured vane surface temperatures. The trailing edge turns out to be subjected to high thermal loads as it is too thin to be cooled effectively. Secondary flow phenomena like the passage vortex and the corner vortex and their impact on the temperature distribution are discussed. The ZrO2 coating is calculated for a thickness of 300μm. The substrate material temperatures are lowered by about 20 K–29 K in the stagnation point area and by about 27 K–43 K in the shock area on the suction side. At the trailing edge, the coating on the suction side and on the pressure side hardly influences the metal temperature.

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.

Conjugate heat transfer modeling of a turbine vane endwall with thermal barrier coatings

2019 ◽  
Vol 123 (1270) ◽  
pp. 1959-1981 ◽  
Author(s):  
Xing Yang ◽  
Zhenping Feng ◽  
Terrence W. Simon
Keyword(s):  
Heat Transfer ◽  
Thermal Barrier Coatings ◽  
Film Cooling ◽  
Conjugate Heat Transfer ◽  
Thermal Protection ◽  
Design Stage ◽  
Thermal Barrier ◽  
Cooling Effectiveness ◽  
Barrier Coatings ◽  
Turbine Vane

ABSTRACTAdvanced cooling techniques involving internal enhanced heat transfer and external film cooling and thermal barrier coatings (TBCs) are employed for gas turbine hot components to reduce metal temperatures and to extend their lifetime. A deeper understanding of the interaction mechanism of these thermal protection methods and the conjugate thermal behaviours of the turbine parts provides valuable guideline for the design stage. In this study, a conjugate heat transfer model of a turbine vane endwall with internal impingement and external film cooling is constructed to document the effects of TBCs on the overall cooling effectiveness using numerical simulations. Experiments on the same model with no TBCs are performed to validate the computational methods. Round and crater holes due to the inclusion of TBCs are investigated as well to address how film-cooling configurations affect the aero-thermal performance of the endwall. Results show that the TBCs have a profound effect in reducing the endwall metal temperatures for both cases. The TBC thermal protection for the endwall is shown to be more significant than the effect of increasing coolant mass flow rate. Although the crater holes have better film cooling performance than the traditional round holes, a slight decrement of overall cooling effectiveness is found for the crater configuration due to more endwall metal surfaces directly exposed to external mainstream flows. Energy loss coefficients at the vane passage exit show a relevant negative impact of adding TBCs on the cascade aerodynamic performance, particularly for the round hole case.

Sign in / Sign up

Export Citation Format

Share Document