Thermal Stress in Volcanic-Ash-Deposited Thermal Barrier Coatings Monitored by Long-Range Laser System

2016 ◽  
Vol 713 ◽  
pp. 293-296
Author(s):  
Masayuki Arai ◽  
Daichi Yamaura
Keyword(s):  
Thermal Stress ◽  
Power Plants ◽  
Volcanic Ash ◽  
Thermal Power ◽  
Laser System ◽  
Tokyo Bay ◽  
Thermal Barrier ◽  
Ash Deposition ◽  
Barrier Coating ◽  
Laser Monitoring

All thermal power plants including gas turbine (GT) of Tokyo electric company are located along Tokyo bay. If Mt. Fuji is exploded, volcanic ash is fallen down in Kanto area. If volcanic ash is inhaled into GTs, the ash would be firstly impacted and deposited onto thermal barrier coating (TBC) of the blades. Such deposition of the volcanic ash causes the delamination of the ceramic coating. In this study, TBC delamination mechanisms due to the volcanic ash deposition is discussed based upon thermal stress evaluated by a laser monitoring measurement system.

Delamination Cracking in Thermal Barrier Coating System

2002 ◽  
Vol 124 (4) ◽  
pp. 922-930 ◽  
Author(s):  
Y. C. Zhou ◽  
T. Hashida
Keyword(s):  
Thermal Stress ◽  
Temperature Gradient ◽  
Thermal Barrier Coating ◽  
Ceramic Coating ◽  
Compressive Load ◽  
Bending Moment ◽  
Thermal Barrier ◽  
Barrier Coating ◽  
Thermal Growth ◽  
Coating Delamination

Delamination cracking in thermal barrier coating (TBC) system is studied with the newly developed theoretical model. A semi-infinite long interface crack is pre-existing. The thermal stress and temperature gradient in TBC system are designated by a membrane stress P and a bending moment M. In this case, the effects of plastic deformation, creep of ceramic coating, as well as thermal growth oxidation and temperature gradient in TBC system are considered in the model due to the fact that these effects are considered in the calculation of thermal stress. The energy release rate, mode I and mode II stress intensity factors, as well as mode mixed measure ψ, are derived. The emphatic discussion about PSZ/Ni-alloy reveals that the TBC system may not fail in the form of coating delamination during the period of heat hold. However, the failure may be in the form of coating delamination during cooling or in the heating period during the second cycle or later cycles. The conclusion is consistent with the experimental observations. The delamination of ceramic coating is induced by the compressive load in the coating.

scholarly journals Effect of Thermal Barrier Coating on the Thermal Stress of Gas Microturbine Blades and Nozzles

2020 ◽  
Vol 66 (10) ◽  
pp. 581-590
Author(s):  
Oscar Tenango-Pirin ◽  
Elva Reynoso-Jardón ◽  
Juan Carlos García ◽  
Yahir Mariaca ◽  
Yuri Sara Hernández ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Thermal Barrier Coating ◽  
Thermal Insulation ◽  
Turbine Blades ◽  
Temperature Fields ◽  
Maximum Temperature ◽  
Thermal Barrier ◽  
New Materials ◽  
Barrier Coating ◽  
Operational Life

Thermal barrier coatings play a key role in the operational life of microturbines because they reduce thermal stress in the turbine components. In this work, numerical computations were carried out to assess new materials developed to be used as a thermal barrier coating for gas turbine blades. The performance of the microturbine components protection is also evaluated. The new materials were 8YSZ, Mg2SiO4, Y3Ce7Ta2O23.5, and Yb3Ce7Ta2O23.5. For testing the materials, a 3D gas microturbine model is developed, in which the fluid-structure interaction is solved using CFD and FEM. Temperature fields and stress magnitudes are calculated on the nozzle and blade, and then these are compared with a case in which no thermal barrier is used. Based on these results, the non-uniform temperature distributions are used to compute the stress levels in nozzles and blades. Higher temperature gradients are observed on the nozzle; the maximum temperature magnitudes are observed in the blades. However, it is found that Mg2SiO4 and Y3Ce7Ta2O23.5 provided better thermal insulation for the turbine components compared with the other evaluated materials. Mg2SiO4 and Y3Ce7Ta2O23.5 presented the best performance regarding stress and thermal insulation for the microturbine components. Keywords: thermal barrier coating, gas microturbine, turbine blade, thermal stress

Novel Thermal Barrier Coatings Resistant to Molten Volcanic Ash Deposition

2019 ◽  
Author(s):  
Siddharth Lokachari ◽  
Wenjia Song ◽  
Masahiro Fukumoto ◽  
Yan Lavallée ◽  
Hongbo Guo ◽  
...  
Keyword(s):  
Thermal Barrier Coatings ◽  
Volcanic Ash ◽  
Thermal Barrier ◽  
Ash Deposition ◽  
Barrier Coatings
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