Dhinesh Thanganadar, F. Fornarelli, S. Camporeale, F. Asfand, K. Patchigolla
Supercritical carbon dioxide (sCO2) cycles are considered to provide a faster response to load change owing to their compact footprint. sCO2 cycles are generally highly recuperative, therefore the response time is mainly dictated by the heat exchanger characteristics. This study model the transient behaviour of a recuperator in 10 MWe simple recuperative Brayton cycle. The response for the variation of inlet temperature and mass flow boundary conditions were investigated using two approaches based on temperature and enthalpy. The performance of these two approaches are compared and the numerical schemes were discussed along with the challenges encountered. The simulation results were validated against the experimental data available in the literature with a fair agreement. The characteristic time of the heat exchanger for a step change of the boundary conditions is reported that supports the recuperator design process. Compact recuperator responded in less than 20 seconds for the changes in the temperature boundary condition whilst it can take upto 1.5 minutes for mass flow change. In order to reduce the computational effort, a logarithmic indexed lookup table approach is presented, reducing the simulation time by a factor of 20.
{"title":"Recuperator Transient Simulation for Supercritical Carbon Dioxide Cycle in CSP Applications","authors":"Dhinesh Thanganadar, F. Fornarelli, S. Camporeale, F. Asfand, K. Patchigolla","doi":"10.1115/GT2020-14785","DOIUrl":"https://doi.org/10.1115/GT2020-14785","url":null,"abstract":"\u0000 Supercritical carbon dioxide (sCO2) cycles are considered to provide a faster response to load change owing to their compact footprint. sCO2 cycles are generally highly recuperative, therefore the response time is mainly dictated by the heat exchanger characteristics. This study model the transient behaviour of a recuperator in 10 MWe simple recuperative Brayton cycle. The response for the variation of inlet temperature and mass flow boundary conditions were investigated using two approaches based on temperature and enthalpy. The performance of these two approaches are compared and the numerical schemes were discussed along with the challenges encountered. The simulation results were validated against the experimental data available in the literature with a fair agreement. The characteristic time of the heat exchanger for a step change of the boundary conditions is reported that supports the recuperator design process. Compact recuperator responded in less than 20 seconds for the changes in the temperature boundary condition whilst it can take upto 1.5 minutes for mass flow change. In order to reduce the computational effort, a logarithmic indexed lookup table approach is presented, reducing the simulation time by a factor of 20.","PeriodicalId":186943,"journal":{"name":"Volume 11: Structures and Dynamics: Structural Mechanics, Vibration, and Damping; Supercritical CO2","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115208075","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}
Jie-Hong Yuan, C. Schwingshackl, L. Salles, Chian Wong, S. Patsias
Localized nonlinearities due to the contact friction interfaces are widely present in the aero-engine structures. They can significantly reduce the vibration amplitudes and shift the resonance frequencies away from critical operating speeds, by exploiting the frictional energy dissipation at the contact interface. However, the modelling capability to predict the dynamics of such large-scale systems with these nonlinearities is often impeded by the high computational expense. Component mode synthesis (CMS) based reduced order modelling (ROM) are commonly used to overcome this problem in jointed structures. However, the computational efficiency of these classical ROMs are sometimes limited as their size is proportional to the DOFs of joint interfaces resulting in a full dense matrix. A new ROM based on an adaptive formulation is proposed in this paper to improve the CMS methods for reliable predictions of the dynamics in jointed structures. This new ROM approach is able to adaptively switch the sticking contact nodes off during the online computation leading to a significant size reduction comparing to the CMS based models. The large-scale high fidelity fan blade assembly is used as the case study. The forced response obtained from the novel ROM is compared to the state-of-the-art CMS based Craig-Bampton method. A parametric study is then carried out to assess the influence of the contact parameters on the dynamics of the fan assembly. The feasibility of using this proposed method for nonlinear modal analysis is also characterised.
{"title":"Reduced Order Method Based on an Adaptive Formulation and its Application to Fan Blade System With Dovetail Joints","authors":"Jie-Hong Yuan, C. Schwingshackl, L. Salles, Chian Wong, S. Patsias","doi":"10.1115/GT2020-14227","DOIUrl":"https://doi.org/10.1115/GT2020-14227","url":null,"abstract":"\u0000 Localized nonlinearities due to the contact friction interfaces are widely present in the aero-engine structures. They can significantly reduce the vibration amplitudes and shift the resonance frequencies away from critical operating speeds, by exploiting the frictional energy dissipation at the contact interface. However, the modelling capability to predict the dynamics of such large-scale systems with these nonlinearities is often impeded by the high computational expense. Component mode synthesis (CMS) based reduced order modelling (ROM) are commonly used to overcome this problem in jointed structures. However, the computational efficiency of these classical ROMs are sometimes limited as their size is proportional to the DOFs of joint interfaces resulting in a full dense matrix. A new ROM based on an adaptive formulation is proposed in this paper to improve the CMS methods for reliable predictions of the dynamics in jointed structures. This new ROM approach is able to adaptively switch the sticking contact nodes off during the online computation leading to a significant size reduction comparing to the CMS based models. The large-scale high fidelity fan blade assembly is used as the case study. The forced response obtained from the novel ROM is compared to the state-of-the-art CMS based Craig-Bampton method. A parametric study is then carried out to assess the influence of the contact parameters on the dynamics of the fan assembly. The feasibility of using this proposed method for nonlinear modal analysis is also characterised.","PeriodicalId":186943,"journal":{"name":"Volume 11: Structures and Dynamics: Structural Mechanics, Vibration, and Damping; Supercritical CO2","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126490096","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}
In the near future, due to the growing share of variable renewable energy (VRE) in the electricity mix and the lack of large-scale electricity storage, coal power plants will have to gradually shift their role from base-load operation to providing fluctuating back-up power to meet unpredictable and short-noticed load variations, in order to improve the stability of the electrical grid. However, current coal power plants have been designed to operate at base-load and are not optimized for flexible part-load operation, resulting in an intrinsic inadequacy for fast load variations. The founding idea of the H2020 sCO2-Flex project is to improve the flexibility of pulverized coal power plants by adopting supercritical carbon dioxide (sCO2) Brayton power cycles instead of common steam Rankine cycles. Despite the extensive available literature about the design of sCO2 power systems for different applications (concentrating solar power, waste heat recovery, 4th generation nuclear), there is still limited knowledge about part-load strategies that should be implemented in order to maximize system efficiency during real plant operation. This paper aims to provide a deeper insight about the potential of sCO2 power plants for small modular coal power plants (25–100 MWel) highlighting the difficulties that must be faced during part-load operation in order to ensure high system performances still guaranteeing a safe operation of the cycle components. The selected configuration is a recompressed cycle with high temperature recuperator bypass which is modelled in a MATLAB+REFPROP numerical tool specifically developed to optimize the plant nominal performance, to provide a preliminary sizing of each component and to evaluate and compare different off-design operating strategies. In particular, the off-design behavior and the operational constraints of each component will be implemented based on referenced numerical models, adopting reliable correlations and exploiting ad hoc codes for the performance evaluation.
{"title":"Part Load Strategy Definition and Annual Simulation for Small Size sCO2 Based Pulverized Coal Power Plant","authors":"Dario Alfani, M. Astolfi, M. Binotti, Paolo Silva","doi":"10.1115/GT2020-15541","DOIUrl":"https://doi.org/10.1115/GT2020-15541","url":null,"abstract":"\u0000 In the near future, due to the growing share of variable renewable energy (VRE) in the electricity mix and the lack of large-scale electricity storage, coal power plants will have to gradually shift their role from base-load operation to providing fluctuating back-up power to meet unpredictable and short-noticed load variations, in order to improve the stability of the electrical grid. However, current coal power plants have been designed to operate at base-load and are not optimized for flexible part-load operation, resulting in an intrinsic inadequacy for fast load variations. The founding idea of the H2020 sCO2-Flex project is to improve the flexibility of pulverized coal power plants by adopting supercritical carbon dioxide (sCO2) Brayton power cycles instead of common steam Rankine cycles. Despite the extensive available literature about the design of sCO2 power systems for different applications (concentrating solar power, waste heat recovery, 4th generation nuclear), there is still limited knowledge about part-load strategies that should be implemented in order to maximize system efficiency during real plant operation. This paper aims to provide a deeper insight about the potential of sCO2 power plants for small modular coal power plants (25–100 MWel) highlighting the difficulties that must be faced during part-load operation in order to ensure high system performances still guaranteeing a safe operation of the cycle components. The selected configuration is a recompressed cycle with high temperature recuperator bypass which is modelled in a MATLAB+REFPROP numerical tool specifically developed to optimize the plant nominal performance, to provide a preliminary sizing of each component and to evaluate and compare different off-design operating strategies. In particular, the off-design behavior and the operational constraints of each component will be implemented based on referenced numerical models, adopting reliable correlations and exploiting ad hoc codes for the performance evaluation.","PeriodicalId":186943,"journal":{"name":"Volume 11: Structures and Dynamics: Structural Mechanics, Vibration, and Damping; Supercritical CO2","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134571069","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}
An effective method is developed for the efficient calculation of the transient vibration response for mistuned bladed disks under complex excitation and varying rotation speeds. The method uses the large-scale finite element modelling of the bladed disks allowing the accurate description of the dynamic properties of the mistuned bladed disks. The realistic distributions of the excitation forces are considered, which resulted in the multiharmonic excitation loads. The transient response calculation is based on the analytically derived expressions for the transient forced response and the effective method used for the model reduction. The effects of the varying rotation speed on the natural frequencies and mode shapes of the mistuned bladed disk and its effects on the amplitude and the spectral composition of the loading are allowed for. The different functions of the rotation speed variation can be analyzed. Numerical studies of the transient forced response and the amplitude amplification in mistuned bladed disks are performed when the resonance regimes are passed during gas-turbine engine acceleration or deceleration. The effects of different types of excitation force and mistuning on transient amplitude amplification are illustrated by a large number of the computational results and comparative analysis. These results and analysis of transient forced response are shown on an example of a realistic mistuned bladed disk.
{"title":"High Fidelity Transient Forced Response Analysis of Mistuned Bladed Disks Under Complex Excitation and Variable Rotation Speeds","authors":"Jing Tong, C. Zang, E. Petrov","doi":"10.1115/GT2020-15223","DOIUrl":"https://doi.org/10.1115/GT2020-15223","url":null,"abstract":"\u0000 An effective method is developed for the efficient calculation of the transient vibration response for mistuned bladed disks under complex excitation and varying rotation speeds. The method uses the large-scale finite element modelling of the bladed disks allowing the accurate description of the dynamic properties of the mistuned bladed disks. The realistic distributions of the excitation forces are considered, which resulted in the multiharmonic excitation loads. The transient response calculation is based on the analytically derived expressions for the transient forced response and the effective method used for the model reduction.\u0000 The effects of the varying rotation speed on the natural frequencies and mode shapes of the mistuned bladed disk and its effects on the amplitude and the spectral composition of the loading are allowed for. The different functions of the rotation speed variation can be analyzed.\u0000 Numerical studies of the transient forced response and the amplitude amplification in mistuned bladed disks are performed when the resonance regimes are passed during gas-turbine engine acceleration or deceleration. The effects of different types of excitation force and mistuning on transient amplitude amplification are illustrated by a large number of the computational results and comparative analysis. These results and analysis of transient forced response are shown on an example of a realistic mistuned bladed disk.","PeriodicalId":186943,"journal":{"name":"Volume 11: Structures and Dynamics: Structural Mechanics, Vibration, and Damping; Supercritical CO2","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133551329","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}
E. Ferhatoglu, S. Zucca, D. Botto, J. Auciello, Lorenzo Arcangeli
Friction dampers are one of the most common structures used to alleviate excessive vibration amplitudes in turbomachinery applications. There are very well-known types of contact elements exploited efficiently, such as underplatform dampers. However, different design approach is sometimes needed to maximize the effectiveness further. In this paper, computational forced response prediction of bladed disks with a configuration of the secondary structure commonly used by Baker Hughes design, the so-called mid-span dampers, is presented. Mid-span dampers are metal devices positioned at the middle section of the airfoil span and come into contact with the blade by the centrifugal force acting during rotation. Proposed damping mechanism is applied to a realistic steam turbine bladed disk under cyclic symmetric boundary conditions. Friction contact is modeled through a large number of contact nodes between the blade and the damper by using a 2D friction contact element with variable normal load. Harmonic Balance Method and Alternating Frequency/Time approach are utilized to obtain nonlinear algebraic equations in frequency domain and nonlinear forced response is computed by using Newton-Raphson method. The results obtained by numerical simulations show that mid-span dampers are an efficient configuration type of a damping mechanism to be used in the design of the bladed disks for nonlinear vibration analysis.
{"title":"Nonlinear Vibration Analysis of Turbine Bladed Disks With Mid-Span Dampers","authors":"E. Ferhatoglu, S. Zucca, D. Botto, J. Auciello, Lorenzo Arcangeli","doi":"10.1115/GT2020-14942","DOIUrl":"https://doi.org/10.1115/GT2020-14942","url":null,"abstract":"\u0000 Friction dampers are one of the most common structures used to alleviate excessive vibration amplitudes in turbomachinery applications. There are very well-known types of contact elements exploited efficiently, such as underplatform dampers. However, different design approach is sometimes needed to maximize the effectiveness further. In this paper, computational forced response prediction of bladed disks with a configuration of the secondary structure commonly used by Baker Hughes design, the so-called mid-span dampers, is presented. Mid-span dampers are metal devices positioned at the middle section of the airfoil span and come into contact with the blade by the centrifugal force acting during rotation. Proposed damping mechanism is applied to a realistic steam turbine bladed disk under cyclic symmetric boundary conditions. Friction contact is modeled through a large number of contact nodes between the blade and the damper by using a 2D friction contact element with variable normal load. Harmonic Balance Method and Alternating Frequency/Time approach are utilized to obtain nonlinear algebraic equations in frequency domain and nonlinear forced response is computed by using Newton-Raphson method. The results obtained by numerical simulations show that mid-span dampers are an efficient configuration type of a damping mechanism to be used in the design of the bladed disks for nonlinear vibration analysis.","PeriodicalId":186943,"journal":{"name":"Volume 11: Structures and Dynamics: Structural Mechanics, Vibration, and Damping; Supercritical CO2","volume":"12 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125448682","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}
J. Marion, B. LaRiviere, Aaron Mcclung, J. Mortzheim, Robin W. Ames
A team led by Gas Technology Institute (GTI®), Southwest Research Institute® (SwRI®) and General Electric Global Research (GE-GR), along with the University of Wisconsin and Natural Resources Canada (NRCan), is actively executing a project called “STEP” [Supercritical Transformational Electric Power project], to design, construct, commission, and operate an integrated and reconfigurable 10 MWe sCO2 [supercritical CO2] Pilot Plant Test Facility. The $122* million project is funded $84 million by the US DOE’s National Energy Technology Laboratory (NETL Award Number DE-FE0028979) and $38* million by the team members, component suppliers and others interested in sCO2 technology. The facility is currently under construction and is located at SwRI’s San Antonio, Texas, USA campus. This project is a significant step toward sCO2 cycle based power generation commercialization and is informing the performance, operability, and scale-up to commercial plants. Significant progress has been made. The design phase is complete (Phase 1) and included procurements of long-lead time deliver components. Now well into Phase 2, most major equipment is in fabrication and several completed and delivered. These efforts have already provided valuable project learnings for technology commercialization. A ground-breaking was held in October of 2018 and now civil work and the construction of a dedicated 25,000 ft2 building has progressed and is largely completed at the San Antonio, TX, USA project site. Supercritical CO2 (sCO2) power cycles are Brayton cycles that utilize supercritical CO2 working fluid to convert heat to power. They offer the potential for higher system efficiencies than other energy conversion technologies such as steam Rankine or Organic Rankine cycles this especially when operating at elevated temperatures. sCO2 power cycles are being considered for a wide range of applications including fossil-fired systems, waste heat recovery, concentrated solar power, and nuclear power generation. By the end of this 6-year STEP pilot demo project, the operability of the sCO2 power cycle will be demonstrated and documented starting with facility commissioning as a simple closed recuperated cycle configuration initially operating at a 500°C (932°F) turbine inlet temperature and progressing to a recompression closed Brayton cycle technology (RCBC) configuration operating at 715°C (1319 °F).
{"title":"The STEP 10 MWe sCO2 Pilot Demonstration Status Update","authors":"J. Marion, B. LaRiviere, Aaron Mcclung, J. Mortzheim, Robin W. Ames","doi":"10.1115/GT2020-14334","DOIUrl":"https://doi.org/10.1115/GT2020-14334","url":null,"abstract":"\u0000 A team led by Gas Technology Institute (GTI®), Southwest Research Institute® (SwRI®) and General Electric Global Research (GE-GR), along with the University of Wisconsin and Natural Resources Canada (NRCan), is actively executing a project called “STEP” [Supercritical Transformational Electric Power project], to design, construct, commission, and operate an integrated and reconfigurable 10 MWe sCO2 [supercritical CO2] Pilot Plant Test Facility. The $122* million project is funded $84 million by the US DOE’s National Energy Technology Laboratory (NETL Award Number DE-FE0028979) and $38* million by the team members, component suppliers and others interested in sCO2 technology. The facility is currently under construction and is located at SwRI’s San Antonio, Texas, USA campus. This project is a significant step toward sCO2 cycle based power generation commercialization and is informing the performance, operability, and scale-up to commercial plants.\u0000 Significant progress has been made. The design phase is complete (Phase 1) and included procurements of long-lead time deliver components. Now well into Phase 2, most major equipment is in fabrication and several completed and delivered. These efforts have already provided valuable project learnings for technology commercialization. A ground-breaking was held in October of 2018 and now civil work and the construction of a dedicated 25,000 ft2 building has progressed and is largely completed at the San Antonio, TX, USA project site.\u0000 Supercritical CO2 (sCO2) power cycles are Brayton cycles that utilize supercritical CO2 working fluid to convert heat to power. They offer the potential for higher system efficiencies than other energy conversion technologies such as steam Rankine or Organic Rankine cycles this especially when operating at elevated temperatures. sCO2 power cycles are being considered for a wide range of applications including fossil-fired systems, waste heat recovery, concentrated solar power, and nuclear power generation.\u0000 By the end of this 6-year STEP pilot demo project, the operability of the sCO2 power cycle will be demonstrated and documented starting with facility commissioning as a simple closed recuperated cycle configuration initially operating at a 500°C (932°F) turbine inlet temperature and progressing to a recompression closed Brayton cycle technology (RCBC) configuration operating at 715°C (1319 °F).","PeriodicalId":186943,"journal":{"name":"Volume 11: Structures and Dynamics: Structural Mechanics, Vibration, and Damping; Supercritical CO2","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115107860","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}
To date variety of supercritical CO2 cycles were proposed by numerous authors. Multiple small-scale tests performed, and a lot of supercritical CO cycle aspects studied. Currently, 3-10 MW-scale test facilities are being built. However, there are still several pieces of SCO2 technology with the Technology Readiness Level (TRL) 3-5 and system modeling is one of them. The system modeling approach shall be sufficiently accurate and flexible, to be able to precisely predict the off-design and part-load operation of the cycle at both supercritical and condensing modes with diverse control strategies. System modeling itself implies the utilization of component models which are often idealized and may not provide a sufficient level of fidelity. Especially for prediction of off-design and part load supercritical CO2 cycle performance with near-critical compressor and transition to condensing modes with lower ambient temperatures, and other aspects of cycle operation under alternating grid demands and ambient conditions. In this study, the concept of a digital twin to predict off-design supercritical CO2 cycle performance is utilized. In particular, with the intent to have sufficient cycle simulation accuracy and flexibility the cycle simulation system with physics-based methods/modules were created for the bottoming 15.5 MW Power Generation Unit (PGU). The heat source for PGU is GE LM6000-PH DLE gas turbine. The PGU is a composite (merged) supercritical CO2 cycle with a high heat recovery rate, its design and the overall scheme are described in detail. The calculation methods utilized at cycle level and components’ level, including loss models with an indication of prediction accuracy, are described. The flowchart of the process of off-design performance estimation and data transfer between the modules as well. The comparison of the results obtained utilizing PGU digital twin with other simplified approaches is performed. The results of the developed digital twin utilization to optimize cycle control strategies and parameters to improve off-design cycle performance are discussed in detail.
{"title":"Application of Digital Twin Concept for Supercritical CO2 Off-Design Performance and Operation Analyses","authors":"L. Moroz, M. Burlaka, T. Zhang, O. Altukhova","doi":"10.1115/GT2020-15743","DOIUrl":"https://doi.org/10.1115/GT2020-15743","url":null,"abstract":"\u0000 To date variety of supercritical CO2 cycles were proposed by numerous authors. Multiple small-scale tests performed, and a lot of supercritical CO cycle aspects studied. Currently, 3-10 MW-scale test facilities are being built. However, there are still several pieces of SCO2 technology with the Technology Readiness Level (TRL) 3-5 and system modeling is one of them. The system modeling approach shall be sufficiently accurate and flexible, to be able to precisely predict the off-design and part-load operation of the cycle at both supercritical and condensing modes with diverse control strategies. System modeling itself implies the utilization of component models which are often idealized and may not provide a sufficient level of fidelity. Especially for prediction of off-design and part load supercritical CO2 cycle performance with near-critical compressor and transition to condensing modes with lower ambient temperatures, and other aspects of cycle operation under alternating grid demands and ambient conditions.\u0000 In this study, the concept of a digital twin to predict off-design supercritical CO2 cycle performance is utilized. In particular, with the intent to have sufficient cycle simulation accuracy and flexibility the cycle simulation system with physics-based methods/modules were created for the bottoming 15.5 MW Power Generation Unit (PGU). The heat source for PGU is GE LM6000-PH DLE gas turbine. The PGU is a composite (merged) supercritical CO2 cycle with a high heat recovery rate, its design and the overall scheme are described in detail. The calculation methods utilized at cycle level and components’ level, including loss models with an indication of prediction accuracy, are described. The flowchart of the process of off-design performance estimation and data transfer between the modules as well. The comparison of the results obtained utilizing PGU digital twin with other simplified approaches is performed. The results of the developed digital twin utilization to optimize cycle control strategies and parameters to improve off-design cycle performance are discussed in detail.","PeriodicalId":186943,"journal":{"name":"Volume 11: Structures and Dynamics: Structural Mechanics, Vibration, and Damping; Supercritical CO2","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125363487","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. Zambon, A. Hosangadi, T. Weathers, Mark Winquist, J. Mays, Shinjiro Miyata, G. Subbaraman
The challenge in the design of oxy-combustors for direct-fired supercritical CO2 (sCO2) cycles is in addressing disparate performance metrics and objectives. Key design parameters to consider include among others: injector design for mixing and flame stability, split of recycled CO2 diluent between injectors and cooling films, target flame temperatures to control non-condensable products, and strategies to inject the diluent CO2 for film cooling and thermal control. In order to support novel oxy-combustor designs, a high-fidelity yet numerically efficient modeling framework based on the CRUNCH CFD® flow solver is presented, featuring key physics-based sub-models relevant in this regime. For computational efficiency in modeling large kinetic sets, a flamelet/progress variable (FPV) based tabulatedchemistry approach is utilized featuring a three-stream extension to allow for the simulation of the CO2 film cooling stream in addition to the fuel and oxidizer streams. Finite-rate chemistry effects are modeled in terms of multiple progress variables for the primary flame as well as for slower-evolving chemical species such as NOx and SOx contaminants. Real fluid effects are modeled using advanced equations of states. The predictive capabilities of this computationally-tractable design support tool are demonstrated on a conceptual injector design for an oxy-combustor operating near 30 MPa. Simulations results provide quantitative feedback on the effectiveness of the film cooling as well as the level of contaminants (CO, NO, and N) in the exhaust due to impurities entering from the injectors. These results indicate that this framework would be a useful tool for refining and optimizing the oxy-combustor designs as well as risk mitigation analyses.
{"title":"A High-Fidelity Modeling Tool to Support the Design of Oxy-Combustors for Direct-Fired sCO2 Cycles","authors":"A. Zambon, A. Hosangadi, T. Weathers, Mark Winquist, J. Mays, Shinjiro Miyata, G. Subbaraman","doi":"10.1115/GT2020-14406","DOIUrl":"https://doi.org/10.1115/GT2020-14406","url":null,"abstract":"\u0000 The challenge in the design of oxy-combustors for direct-fired supercritical CO2 (sCO2) cycles is in addressing disparate performance metrics and objectives. Key design parameters to consider include among others: injector design for mixing and flame stability, split of recycled CO2 diluent between injectors and cooling films, target flame temperatures to control non-condensable products, and strategies to inject the diluent CO2 for film cooling and thermal control. In order to support novel oxy-combustor designs, a high-fidelity yet numerically efficient modeling framework based on the CRUNCH CFD® flow solver is presented, featuring key physics-based sub-models relevant in this regime. For computational efficiency in modeling large kinetic sets, a flamelet/progress variable (FPV) based tabulatedchemistry approach is utilized featuring a three-stream extension to allow for the simulation of the CO2 film cooling stream in addition to the fuel and oxidizer streams. Finite-rate chemistry effects are modeled in terms of multiple progress variables for the primary flame as well as for slower-evolving chemical species such as NOx and SOx contaminants. Real fluid effects are modeled using advanced equations of states. The predictive capabilities of this computationally-tractable design support tool are demonstrated on a conceptual injector design for an oxy-combustor operating near 30 MPa. Simulations results provide quantitative feedback on the effectiveness of the film cooling as well as the level of contaminants (CO, NO, and N) in the exhaust due to impurities entering from the injectors. These results indicate that this framework would be a useful tool for refining and optimizing the oxy-combustor designs as well as risk mitigation analyses.","PeriodicalId":186943,"journal":{"name":"Volume 11: Structures and Dynamics: Structural Mechanics, Vibration, and Damping; Supercritical CO2","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130868664","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 dry gas seal is a promising sealing technology to control the leakage flow through the clearance between the stationary and rotational components of Supercritical Carbon Dioxide (SCO2) turbomachinery. The dry gas seal is firstly designed for the SCO2 compressor shaft end of the GE’s 450MWe Brayton cycle power generation system. Then the effects of the spiral angle and gas film thickness on the designed dry gas seal performance are numerically investigated using the three-dimensional Reynolds-Averaged Navier-Stokes (RANS) and SST turbulence model. The accuracy of the numerical method is validated by comparison of the previous research data done by Gabriel et al. with air as the working fluid. The Current study analyzed the sealing performance parameters of the designed dry gas seal for SCO2 compressor shaft end at five gas film thicknesses and four spiral angles. These parameters include: opening force, leakage rate, stiffness, and opening force leakage ratio. Also, the impacts of the spiral angle on flow direction in the fluid film are analyzed. The obtained results show that the designed dry gas seal meets the requirement of the leakage flow rate of the SCO2 compressor shaft end. The dry gas seal with a spiral angle of 15° is the best solution due to its low leakage rate and its’ best comprehensive sealing performance. On some occasions where high stability is required, the dry gas seal with a spiral angle of 30° can be selected due to its’ highest film stiffness. The present work provides the reference of the dry gas seal design for the SCO2 compressor shaft end.
干气密封是一种很有前途的密封技术，用于控制超临界二氧化碳(SCO2)涡轮机械固定部件和旋转部件之间间隙的泄漏流量。干气密封首先设计用于GE 450MWe Brayton循环发电系统的SCO2压缩机轴端。然后利用三维reynolds - average Navier-Stokes (RANS)湍流模型和SST湍流模型，数值研究了螺旋角和气膜厚度对设计的干气密封性能的影响。通过与Gabriel等先前以空气为工质的研究数据对比，验证了数值方法的准确性。本研究对设计的SCO2压缩机轴端干气密封在5种气膜厚度和4个螺旋角下的密封性能参数进行了分析。这些参数包括:开启力、泄漏率、刚度、开启力泄漏比。分析了螺旋角对液膜内流动方向的影响。计算结果表明，所设计的干气密封满足SCO2压缩机轴端泄漏流量的要求。螺旋角为15°的干气密封泄漏率低，综合密封性能最好，是最佳的解决方案。在一些需要高稳定性的场合，由于其最高的膜刚度，可以选择螺旋角为30°的干气密封。为SCO2压缩机轴端干气密封设计提供参考。
{"title":"Design and Investigations on Dry Gas Seal of the Shaft End for 450MWe Supercritical Carbon Dioxide Compressor","authors":"Tao Yuan, Zhigang Li, Jun Li, Q. Yuan","doi":"10.1115/GT2020-14586","DOIUrl":"https://doi.org/10.1115/GT2020-14586","url":null,"abstract":"\u0000 The dry gas seal is a promising sealing technology to control the leakage flow through the clearance between the stationary and rotational components of Supercritical Carbon Dioxide (SCO2) turbomachinery. The dry gas seal is firstly designed for the SCO2 compressor shaft end of the GE’s 450MWe Brayton cycle power generation system. Then the effects of the spiral angle and gas film thickness on the designed dry gas seal performance are numerically investigated using the three-dimensional Reynolds-Averaged Navier-Stokes (RANS) and SST turbulence model. The accuracy of the numerical method is validated by comparison of the previous research data done by Gabriel et al. with air as the working fluid. The Current study analyzed the sealing performance parameters of the designed dry gas seal for SCO2 compressor shaft end at five gas film thicknesses and four spiral angles. These parameters include: opening force, leakage rate, stiffness, and opening force leakage ratio. Also, the impacts of the spiral angle on flow direction in the fluid film are analyzed. The obtained results show that the designed dry gas seal meets the requirement of the leakage flow rate of the SCO2 compressor shaft end. The dry gas seal with a spiral angle of 15° is the best solution due to its low leakage rate and its’ best comprehensive sealing performance. On some occasions where high stability is required, the dry gas seal with a spiral angle of 30° can be selected due to its’ highest film stiffness. The present work provides the reference of the dry gas seal design for the SCO2 compressor shaft end.","PeriodicalId":186943,"journal":{"name":"Volume 11: Structures and Dynamics: Structural Mechanics, Vibration, and Damping; Supercritical CO2","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121066790","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}
Typical turbofan engine-support-structure systems having a high thrust-to-weight ratio are light, and the structure primarily comprises a plate and shells. The local vibration response of the support structure is excessively large when different frequency loads are applied. A structural vibration response control method based on dry friction damping is proposed to control the excessive vibration response. A dry friction damper with dynamic suction was designed to enhance the damping characteristics of the rotor supporting structure system in the wide frequency domain, without sacrificing the dynamic stiffness of the structure. The system is designed to effectively control the vibration response of the supporting structure at the working-speed frequency. Through theoretical modeling and simulation analyses, the influence of friction contact and damper structure characteristics on the damping effect is described quantitatively. Furthermore, the design idea and the damping process of the supporting structure are described. The calculation results show that the contact friction of the dry friction damper can consume the vibration energy of the supporting frame. A reasonable design of the contact characteristics and geometric configuration parameters of the damper can further optimize the vibration-reduction effect, and thereby improve the vibration response control design of the supporting structure system of aeroengines.
{"title":"Research on Damping Vibration Reduction Design Method of Aeroengine Supporting Structure System","authors":"Chao Li, B. Lei, Yanhong Ma, Jie Hong","doi":"10.1115/GT2020-16316","DOIUrl":"https://doi.org/10.1115/GT2020-16316","url":null,"abstract":"\u0000 Typical turbofan engine-support-structure systems having a high thrust-to-weight ratio are light, and the structure primarily comprises a plate and shells. The local vibration response of the support structure is excessively large when different frequency loads are applied. A structural vibration response control method based on dry friction damping is proposed to control the excessive vibration response. A dry friction damper with dynamic suction was designed to enhance the damping characteristics of the rotor supporting structure system in the wide frequency domain, without sacrificing the dynamic stiffness of the structure. The system is designed to effectively control the vibration response of the supporting structure at the working-speed frequency. Through theoretical modeling and simulation analyses, the influence of friction contact and damper structure characteristics on the damping effect is described quantitatively. Furthermore, the design idea and the damping process of the supporting structure are described. The calculation results show that the contact friction of the dry friction damper can consume the vibration energy of the supporting frame. A reasonable design of the contact characteristics and geometric configuration parameters of the damper can further optimize the vibration-reduction effect, and thereby improve the vibration response control design of the supporting structure system of aeroengines.","PeriodicalId":186943,"journal":{"name":"Volume 11: Structures and Dynamics: Structural Mechanics, Vibration, and Damping; Supercritical CO2","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121069064","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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