{"title":"Influence of Microstructural Change on Crack Growth in Thermal Barrier Coating Subjected to Thermal Cycling under Temperature Gradient","authors":"R. Kitazawa, M. Okada, Takayuki Ozeki","doi":"10.38036/jgpp.14.1_1","DOIUrl":"https://doi.org/10.38036/jgpp.14.1_1","url":null,"abstract":"","PeriodicalId":38948,"journal":{"name":"International Journal of Gas Turbine, Propulsion and Power Systems","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41681236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Surrogate models for predicting transient change in temperature, stress and strain in gas turbine blade","authors":"E. Sakai, Toshihiko Takahashi","doi":"10.38036/jgpp.14.2_1","DOIUrl":"https://doi.org/10.38036/jgpp.14.2_1","url":null,"abstract":"","PeriodicalId":38948,"journal":{"name":"International Journal of Gas Turbine, Propulsion and Power Systems","volume":"80 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70080042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Okada, R. Kitazawa, Toshihiko Takahashi, Takayuki Ozeki
Thermal cycling tests are carried out under a temperature gradient using specimens of thermal barrier coating (TBC). Vertical cracks in the topcoat grow in the direction of the coating thickness, and transverse cracks in the topcoat, which can lead to delamination, grow in the vicinity of the interface with the bondcoat. At a temperature of 1223 K at the substrate surface, with a heat flux of 1.39 MW/m 2 , remarkable growth of transverse cracks is observed, whereas the growth is slower at lower temperatures and heat flux conditions. The transverse crack growth is evaluated using the energy release rate based on Hutchinson’s method. Further, the energy release rate is calculated for a TBC on an in-service blade of an F-class gas turbine. For this, the results from a numerical simulation for the temperature distribution of the blade are used. The criteria for crack growth that can lead to TBC delamination are discussed.
{"title":"Crack Growth in Thermal Barrier Coating Subjected to Thermal Cycling under Temperature Gradient","authors":"M. Okada, R. Kitazawa, Toshihiko Takahashi, Takayuki Ozeki","doi":"10.38036/jgpp.13.3_7","DOIUrl":"https://doi.org/10.38036/jgpp.13.3_7","url":null,"abstract":"Thermal cycling tests are carried out under a temperature gradient using specimens of thermal barrier coating (TBC). Vertical cracks in the topcoat grow in the direction of the coating thickness, and transverse cracks in the topcoat, which can lead to delamination, grow in the vicinity of the interface with the bondcoat. At a temperature of 1223 K at the substrate surface, with a heat flux of 1.39 MW/m 2 , remarkable growth of transverse cracks is observed, whereas the growth is slower at lower temperatures and heat flux conditions. The transverse crack growth is evaluated using the energy release rate based on Hutchinson’s method. Further, the energy release rate is calculated for a TBC on an in-service blade of an F-class gas turbine. For this, the results from a numerical simulation for the temperature distribution of the blade are used. The criteria for crack growth that can lead to TBC delamination are discussed.","PeriodicalId":38948,"journal":{"name":"International Journal of Gas Turbine, Propulsion and Power Systems","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48210619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Water droplet impingement on a low-pressure steam turbine blade causing erosion has been recognized as a crucial issue. It is essential to elucidate a comprehensive droplet detachment mechanism, not only from the trailing edge but also from the liquid film surface. In the present paper, we investigate the influence of interfacial friction factor against liquid film dynamics on a wall sheared by a turbulent gas flow, including the liquid film thickness, liquid film velocity and entrained droplet detached from liquid surface for both pipe flow and plate flow conditions. We conduct the analyses by using a liquid film dynamics model, recently established, considering the three-dimensional destabilized waves and droplet entrainment from the liquid surface. As a result, the film thickness and velocity greatly depends on the interfacial friction factor. Interestingly, the rate of entrained droplet to initial liquid film has a minimum value when the interfacial friction factor equals to the inverse of the liquid film Reynolds number, while the remaining liquid film flow rate becomes maximum.
{"title":"Parametric analysis of interfacial friction factor for liquid film dynamics sheared by turbulent gas flow","authors":"T. Inoue, Y. Kamada, C. Inoue, Zhenying Wang","doi":"10.38036/jgpp.13.3_1","DOIUrl":"https://doi.org/10.38036/jgpp.13.3_1","url":null,"abstract":"Water droplet impingement on a low-pressure steam turbine blade causing erosion has been recognized as a crucial issue. It is essential to elucidate a comprehensive droplet detachment mechanism, not only from the trailing edge but also from the liquid film surface. In the present paper, we investigate the influence of interfacial friction factor against liquid film dynamics on a wall sheared by a turbulent gas flow, including the liquid film thickness, liquid film velocity and entrained droplet detached from liquid surface for both pipe flow and plate flow conditions. We conduct the analyses by using a liquid film dynamics model, recently established, considering the three-dimensional destabilized waves and droplet entrainment from the liquid surface. As a result, the film thickness and velocity greatly depends on the interfacial friction factor. Interestingly, the rate of entrained droplet to initial liquid film has a minimum value when the interfacial friction factor equals to the inverse of the liquid film Reynolds number, while the remaining liquid film flow rate becomes maximum.","PeriodicalId":38948,"journal":{"name":"International Journal of Gas Turbine, Propulsion and Power Systems","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48893746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The role of hydrogen (H 2 ) as a carbon-free energy carrier is discussed since decades for reducing greenhouse gas emissions. As bridge technology towards a hydrogen-based energy supply, fuel mixtures of natural gas or methane (CH 4 ) and hydrogen are possible. The paper presents the first test results of a low-emission Micromix combustor designed for flexible-fuel operation with variable H 2 /CH 4 mixtures. The numerical and experimental approach for considering variable fuel mixtures instead of recently investigated pure hydrogen is described. In the experimental studies, a first generation FuelFlex Micromix combustor geometry is tested at atmospheric pressure at gas turbine operating conditions corresponding to part- and full-load. The H 2 /CH 4 fuel mixture composition is varied between 57 and 100 vol.% hydrogen content. Despite the challenges flexible-fuel operation poses onto the design of a combustion system, the evaluated FuelFlex Micromix prototype shows a significant low NO x performance and high combustion efficiency over a wide fuel range.
{"title":"Flexible Fuel Operation of a Dry-Low-NOx Micromix Combustor with Variable Hydrogen Methane Mixtures","authors":"H. Funke, N. Beckmann","doi":"10.38036/jgpp.13.2_1","DOIUrl":"https://doi.org/10.38036/jgpp.13.2_1","url":null,"abstract":"The role of hydrogen (H 2 ) as a carbon-free energy carrier is discussed since decades for reducing greenhouse gas emissions. As bridge technology towards a hydrogen-based energy supply, fuel mixtures of natural gas or methane (CH 4 ) and hydrogen are possible. The paper presents the first test results of a low-emission Micromix combustor designed for flexible-fuel operation with variable H 2 /CH 4 mixtures. The numerical and experimental approach for considering variable fuel mixtures instead of recently investigated pure hydrogen is described. In the experimental studies, a first generation FuelFlex Micromix combustor geometry is tested at atmospheric pressure at gas turbine operating conditions corresponding to part- and full-load. The H 2 /CH 4 fuel mixture composition is varied between 57 and 100 vol.% hydrogen content. Despite the challenges flexible-fuel operation poses onto the design of a combustion system, the evaluated FuelFlex Micromix prototype shows a significant low NO x performance and high combustion efficiency over a wide fuel range.","PeriodicalId":38948,"journal":{"name":"International Journal of Gas Turbine, Propulsion and Power Systems","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70080502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Panlong Yu, T. Nishiie, T. Kitagawa, Hiroaki Watanabe
The development of turbulent combustion models for a three-feed non-premixed flame is essential for the research of gas-turbine in the oxy-fuel integrated coal gasification combined cycle (IGCC) system. The quasi-two-dimensional flamelet models are considered effective and accurate substitutes for the two-dimensional flamelet model, however, there are still many aspects worth further investigations in terms of each dimension in the flamelet library. The considerations of heat loss, the presumed probability density function (PDF), and the resolution of the diluent fraction in large-eddy simulation (LES) should be attached importance to. In this paper, heat loss, diluent fraction PDF, and resolution of the diluent fraction have been investigated. It has been shown that the current heat loss model in the flamelet equation can correctly interpret the reactions which are facilitated by high temperature. The beta-PDF used for diluent fraction results in a lower temperature in the flame zone than that of the delta-PDF as the diluent fraction fluctuation cannot be overlooked. And also, coarse resolution in terms of the diluent fraction gives interpolation error and shoud be paid attention to.
{"title":"Large-eddy simulation of a three-feed non-premixed flame for an oxy-fuel gas turbine burner","authors":"Panlong Yu, T. Nishiie, T. Kitagawa, Hiroaki Watanabe","doi":"10.38036/jgpp.13.1_1","DOIUrl":"https://doi.org/10.38036/jgpp.13.1_1","url":null,"abstract":"The development of turbulent combustion models for a three-feed non-premixed flame is essential for the research of gas-turbine in the oxy-fuel integrated coal gasification combined cycle (IGCC) system. The quasi-two-dimensional flamelet models are considered effective and accurate substitutes for the two-dimensional flamelet model, however, there are still many aspects worth further investigations in terms of each dimension in the flamelet library. The considerations of heat loss, the presumed probability density function (PDF), and the resolution of the diluent fraction in large-eddy simulation (LES) should be attached importance to. In this paper, heat loss, diluent fraction PDF, and resolution of the diluent fraction have been investigated. It has been shown that the current heat loss model in the flamelet equation can correctly interpret the reactions which are facilitated by high temperature. The beta-PDF used for diluent fraction results in a lower temperature in the flame zone than that of the delta-PDF as the diluent fraction fluctuation cannot be overlooked. And also, coarse resolution in terms of the diluent fraction gives interpolation error and shoud be paid attention to.","PeriodicalId":38948,"journal":{"name":"International Journal of Gas Turbine, Propulsion and Power Systems","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70080444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A large eddy simulation (LES) employing a non-adiabatic flamelet generated manifolds (NA-FGM) approach, which can account for the effects of heat loss, is applied to CH 4 -air super lean premixed combustion fields generated by an axisymmetric jet burner with cooled walls under pressurized conditions. In addition, the validity in predicting the CO emissions is examined. The NA-FGM approach captures the trends of CO emissions well during the experiments, in which the CO emissions increase with a decreasing equivalence ratio. It is shown that the increase in CO emissions for low equivalence ratios is not due to the increase in the CO production, but to the slow rate of CO consumption, which keeps the CO concentration high downstream. The results suggest that capturing such a sensitive reduction of CO consumption rate by heat loss is important for accurately predicting the CO emissions in developing a low-emissions gas turbine combustor at low load.
{"title":"Prediction of CO emissions in turbulent super lean premixed combustion under pressurized conditions using an LES/non-adiabatic FGM approach","authors":"K. Yunoki, T. Nishiie, R. Kurose","doi":"10.38036/jgpp.12.3_1","DOIUrl":"https://doi.org/10.38036/jgpp.12.3_1","url":null,"abstract":"A large eddy simulation (LES) employing a non-adiabatic flamelet generated manifolds (NA-FGM) approach, which can account for the effects of heat loss, is applied to CH 4 -air super lean premixed combustion fields generated by an axisymmetric jet burner with cooled walls under pressurized conditions. In addition, the validity in predicting the CO emissions is examined. The NA-FGM approach captures the trends of CO emissions well during the experiments, in which the CO emissions increase with a decreasing equivalence ratio. It is shown that the increase in CO emissions for low equivalence ratios is not due to the increase in the CO production, but to the slow rate of CO consumption, which keeps the CO concentration high downstream. The results suggest that capturing such a sensitive reduction of CO consumption rate by heat loss is important for accurately predicting the CO emissions in developing a low-emissions gas turbine combustor at low load.","PeriodicalId":38948,"journal":{"name":"International Journal of Gas Turbine, Propulsion and Power Systems","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70080433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Non-axisymmetric contoured endwall can reduce aerodynamic loss in axial turbine if the endwall shape is well designed. Meanwhile, contouring of the endwall can change the value of the total heat flux through the endwall, mainly by changing the distribution of heat transfer coefficient and the endwall area. In this study, several optimized non-axisymmetric contoured endwall shapes are found in an annular cascade passage by a multi-objective optimization process to achieve both improved aerodynamic performance in the passage and more beneficial heat transfer characteristics on the endwall. The optimized contoured endwall designs were found and they are all with sunken area in the middle of the passage and risen area in the aft part of the passage near the suction side. In addition, the case with better heat transfer performance features higher area-averaged heat transfer coefficient but with smaller total endwall area. contouring, as compared to the flat endwall. The total heat transfer was reduced by 2% with a 3.1% reduction in the averaged heat transfer coefficient value and a 1.3% increasing of endwall area value.
{"title":"Multi-Objective Optimization of Non-Axisymmetric Contoured Endwall for Axial Turbines","authors":"Pingting Chen, Xueying Li, Hongde Jiang","doi":"10.38036/JGPP.12.1_1","DOIUrl":"https://doi.org/10.38036/JGPP.12.1_1","url":null,"abstract":"Non-axisymmetric contoured endwall can reduce aerodynamic loss in axial turbine if the endwall shape is well designed. Meanwhile, contouring of the endwall can change the value of the total heat flux through the endwall, mainly by changing the distribution of heat transfer coefficient and the endwall area. In this study, several optimized non-axisymmetric contoured endwall shapes are found in an annular cascade passage by a multi-objective optimization process to achieve both improved aerodynamic performance in the passage and more beneficial heat transfer characteristics on the endwall. The optimized contoured endwall designs were found and they are all with sunken area in the middle of the passage and risen area in the aft part of the passage near the suction side. In addition, the case with better heat transfer performance features higher area-averaged heat transfer coefficient but with smaller total endwall area. contouring, as compared to the flat endwall. The total heat transfer was reduced by 2% with a 3.1% reduction in the averaged heat transfer coefficient value and a 1.3% increasing of endwall area value.","PeriodicalId":38948,"journal":{"name":"International Journal of Gas Turbine, Propulsion and Power Systems","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70080365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Henrik von der Haar, Panagiotis Ignatidis, F. Dinkelacker
A disturbed combustion process in an aircraft engine has an impact on the internal flow and leads to specific irregularities in the species distribution in the exhaust jet. Measuring this distribution provides information about the combustion state and offers the possibility to reduce the engine down-time during inspection. The approach has the potential to improve the resource management as well as the availability and safety of the system. Aim of the research project is to evaluate the state of an aircraft engine by analyzing the emission field in the exhaust jet and using a support vector machine (SVM) algorithm for automatic defect detection and allocation.
{"title":"Experimental and Numerical Based Defect Detection in a Model Combustion Chamber through Machine Learning","authors":"Henrik von der Haar, Panagiotis Ignatidis, F. Dinkelacker","doi":"10.38036/jgpp.12.4_1","DOIUrl":"https://doi.org/10.38036/jgpp.12.4_1","url":null,"abstract":"A disturbed combustion process in an aircraft engine has an impact on the internal flow and leads to specific irregularities in the species distribution in the exhaust jet. Measuring this distribution provides information about the combustion state and offers the possibility to reduce the engine down-time during inspection. The approach has the potential to improve the resource management as well as the availability and safety of the system. Aim of the research project is to evaluate the state of an aircraft engine by analyzing the emission field in the exhaust jet and using a support vector machine (SVM) algorithm for automatic defect detection and allocation.","PeriodicalId":38948,"journal":{"name":"International Journal of Gas Turbine, Propulsion and Power Systems","volume":"106 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70080436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents the interaction between blade vibration and part-span rotating stall in a multi-stage high speed compressor. Unsteady aerodynamic and aeroelastic simulations were conducted using URANS CFD. Steady state computations showed short length scale disturbances formed local to the tip of a front stage rotor. Using a full annulus model, these disturbances were shown to coalesce into flow structures rotating around the annulus at approximately 76% of the shaft rotational speed. Natural evolution of the rotating stall did not result in a coherent spatial pattern. Sensitivity studies showed that operating point and tip clearance have significant impact on the developed state of rotating stall. Subsequent analyses carried out with prescribed rotor blade vibration showed a spatial ‘lock-in’ event where the circumferential order of the part-span rotating stall shifted to match that induced by the vibration mode. Moreover, in contrast to its natural form in the absence of vibration, the fully developed rotating stall showed a coherent stall signal. More importantly, it was found that numerical boundary conditions such as mixing plane and sliding planes can significantly influence the outcome of prediction.
{"title":"Influence of Blade Vibration on Part-Span Rotating Stall","authors":"F. Zhao, J. Dodds, M. Vahdati","doi":"10.33737/jgpps/130873","DOIUrl":"https://doi.org/10.33737/jgpps/130873","url":null,"abstract":"This paper presents the interaction between blade vibration and part-span rotating stall in a multi-stage high speed compressor. Unsteady aerodynamic and aeroelastic simulations were conducted using URANS CFD. Steady state computations showed short length scale disturbances formed local to the tip of a front stage rotor. Using a full annulus model, these disturbances were shown to coalesce into flow structures rotating around the annulus at approximately 76% of the shaft rotational speed. Natural evolution of the rotating stall did not result in a coherent spatial pattern. Sensitivity studies showed that operating point and tip clearance have significant impact on the developed state of rotating stall. Subsequent analyses carried out with prescribed rotor blade vibration showed a spatial ‘lock-in’ event where the circumferential order of the part-span rotating stall shifted to match that induced by the vibration mode. Moreover, in contrast to its natural form in the absence of vibration, the fully developed rotating stall showed a coherent stall signal. More importantly, it was found that numerical boundary conditions such as mixing plane and sliding planes can significantly influence the outcome of prediction.","PeriodicalId":38948,"journal":{"name":"International Journal of Gas Turbine, Propulsion and Power Systems","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69675653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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