A one-dimensional design and dynamic model of a microtube heat exchanger is presented for cooling supercritical CO2 to near critical conditions (35°C and ∼90 bar) with water. A control strategy is designed and implemented to achieve a desired hot-side CO2 outlet temperature, while the cooling-water exit temperature is monitored (ideally kept below 50°C). The control responses during drastic process changes at the boundaries such as sCO2 inlet flow/pressure and cooling water inlet temperature are presented.
{"title":"Modeling and Control of a Supercritical CO2 Water Cooler in an Indirect-Fired 10MWe Recompression Brayton Cycle Near Critical Conditions","authors":"E. Liese, P. Mahapatra, Yuan Jiang","doi":"10.1115/gt2019-90496","DOIUrl":"https://doi.org/10.1115/gt2019-90496","url":null,"abstract":"\u0000 A one-dimensional design and dynamic model of a microtube heat exchanger is presented for cooling supercritical CO2 to near critical conditions (35°C and ∼90 bar) with water. A control strategy is designed and implemented to achieve a desired hot-side CO2 outlet temperature, while the cooling-water exit temperature is monitored (ideally kept below 50°C). The control responses during drastic process changes at the boundaries such as sCO2 inlet flow/pressure and cooling water inlet temperature are presented.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127209754","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}
Samuel Barak, Owen M. Pryor, Erik M. Ninnemann, Sneha Neupane, Xijia Lu, B. Forrest, Subith S. Vasu
In this study, a shock tube is used to investigate combustion tendencies of several fuel mixtures under high carbon dioxide dilution and high fuel loading. Individual mixtures of oxy-syngas and oxy-methane fuels were added to CO2 bath gas environments and ignition delay time data was recorded. Reflected shock pressures maxed around 100 atm, which is above the critical pressure of carbon dioxide in to the supercritical regime. In total, five mixtures were investigated within a temperature range of 1050–1350K. Ignition delay times of all mixtures were compared with predictions of two leading chemical kinetic computer mechanisms for accuracy. The mixtures included four oxy-syngas and one oxy-methane combinations. The experimental data tended to show good agreement with the predictions of literature models for the methane mixture. For all syngas mixtures though the models performed reasonably well at some conditions, predictions were not able to accurately capture the overall behavior. For this reason, there is a need to further investigate the discrepancies in predictions. Additionally, more data must be collected at high pressures to fully understand the chemical kinetic behavior of these mixtures to enable the supercritical CO2 power cycle development.
{"title":"Ignition Delay Times of Syngas and Methane in sCO2 Diluted Mixtures for Direct-Fired Cycles","authors":"Samuel Barak, Owen M. Pryor, Erik M. Ninnemann, Sneha Neupane, Xijia Lu, B. Forrest, Subith S. Vasu","doi":"10.1115/gt2019-90178","DOIUrl":"https://doi.org/10.1115/gt2019-90178","url":null,"abstract":"\u0000 In this study, a shock tube is used to investigate combustion tendencies of several fuel mixtures under high carbon dioxide dilution and high fuel loading. Individual mixtures of oxy-syngas and oxy-methane fuels were added to CO2 bath gas environments and ignition delay time data was recorded. Reflected shock pressures maxed around 100 atm, which is above the critical pressure of carbon dioxide in to the supercritical regime. In total, five mixtures were investigated within a temperature range of 1050–1350K. Ignition delay times of all mixtures were compared with predictions of two leading chemical kinetic computer mechanisms for accuracy. The mixtures included four oxy-syngas and one oxy-methane combinations. The experimental data tended to show good agreement with the predictions of literature models for the methane mixture. For all syngas mixtures though the models performed reasonably well at some conditions, predictions were not able to accurately capture the overall behavior. For this reason, there is a need to further investigate the discrepancies in predictions. Additionally, more data must be collected at high pressures to fully understand the chemical kinetic behavior of these mixtures to enable the supercritical CO2 power cycle development.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122360208","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 increased size of Liquefied Natural Gas (LNG) plants worldwide has led to an increase in boil-off gas (BOG) flows. The BOG can be either liquefied again to LNG or compressed to higher pressure levels for use as fuel gas. Single shaft multistage centrifugal compressors are used to compress large volume of BOG at high pressures. This paper reviews design considerations for synchronous motor driven BOG centrifugal compressors operating at high discharge pressures. Several design features including compressor selection and sizing, auxiliary system, performance characteristics and testing are reviewed. The use of leading power factor synchronous motors to improve the power factor of the LNG plant is discussed. Capability curves of API 546 synchronous motors for operation in VAR control mode — for maintaining constant reactive power — are explained. The choice between the use of speed control or adjustable guide vanes for BOG compressors is discussed.
{"title":"Design Considerations for High Pressure Boil-Off Gas (BOG) Centrifugal Compressors With Synchronous Motor Drives in LNG Liquefaction Plants","authors":"Matt Taher, C. Meher-Homji","doi":"10.1115/gt2019-90329","DOIUrl":"https://doi.org/10.1115/gt2019-90329","url":null,"abstract":"\u0000 The increased size of Liquefied Natural Gas (LNG) plants worldwide has led to an increase in boil-off gas (BOG) flows. The BOG can be either liquefied again to LNG or compressed to higher pressure levels for use as fuel gas. Single shaft multistage centrifugal compressors are used to compress large volume of BOG at high pressures. This paper reviews design considerations for synchronous motor driven BOG centrifugal compressors operating at high discharge pressures. Several design features including compressor selection and sizing, auxiliary system, performance characteristics and testing are reviewed. The use of leading power factor synchronous motors to improve the power factor of the LNG plant is discussed. Capability curves of API 546 synchronous motors for operation in VAR control mode — for maintaining constant reactive power — are explained. The choice between the use of speed control or adjustable guide vanes for BOG compressors is discussed.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"1230 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114088191","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}
Martin Bakken, T. Bjørge, L. Bakken, Ajay Lakshmanan, S. Arulselvan
Today, a few subsea compressor systems are already operating while several new installations are expected within the next years. This creates a need for dynamic simulation tools to ensure proper system design and to facilitate production. The well-known process simulator Hysys Dynamics has been extended to include wet gas compressors, which includes the possibility for the user to input multiple performance curves based on the inlet gas/liquid content. The current paper analyzes the accuracy of the compressor performance procedure within the simulation model when operating with multiple wet performance curves. The findings have been validated against both air/water and hydrocarbon performance data. Further, the affinity laws have extensively been used by the industry and within process simulation tools for performance scaling. Experimental data from the wet gas compressor test facility at the Norwegian University of Science and Technology (NTNU) have been used to validate the applicability of the affinity laws in wet gas flow. The test facility is an open loop configuration consisting of a single shrouded centrifugal impeller, a vaneless diffuser and a circular volute. The test reveals that the compressor performance procedure within the model provides accurate results in both air/water and hydrocarbon flow. Further, for the given application the affinity laws yield a satisfactory estimation in wet gas flow.
{"title":"Wet Gas Compressor Modeling and Performance Scaling","authors":"Martin Bakken, T. Bjørge, L. Bakken, Ajay Lakshmanan, S. Arulselvan","doi":"10.1115/gt2019-90353","DOIUrl":"https://doi.org/10.1115/gt2019-90353","url":null,"abstract":"\u0000 Today, a few subsea compressor systems are already operating while several new installations are expected within the next years. This creates a need for dynamic simulation tools to ensure proper system design and to facilitate production. The well-known process simulator Hysys Dynamics has been extended to include wet gas compressors, which includes the possibility for the user to input multiple performance curves based on the inlet gas/liquid content.\u0000 The current paper analyzes the accuracy of the compressor performance procedure within the simulation model when operating with multiple wet performance curves. The findings have been validated against both air/water and hydrocarbon performance data. Further, the affinity laws have extensively been used by the industry and within process simulation tools for performance scaling. Experimental data from the wet gas compressor test facility at the Norwegian University of Science and Technology (NTNU) have been used to validate the applicability of the affinity laws in wet gas flow. The test facility is an open loop configuration consisting of a single shrouded centrifugal impeller, a vaneless diffuser and a circular volute.\u0000 The test reveals that the compressor performance procedure within the model provides accurate results in both air/water and hydrocarbon flow. Further, for the given application the affinity laws yield a satisfactory estimation in wet gas flow.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115200420","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}
L. Branchini, M. A. Ancona, M. Bianchi, A. D. Pascale, F. Melino, A. Peretto, S. Ottaviano, N. Torricelli, D. Archetti, N. Rossetti, T. Ferrari
The paper investigates the optimum size and potential economic, energetic and environmental benefits of ORC applications, as bottomer section in natural gas compressor stations. Since typical installations consist of multiple gas turbine units in mechanical drive arrangement, operated most of the time under part-load conditions, the economic feasibility of the ORC can become questionable even though the energetic advantage is indisputable. Depending on mechanical drivers profile during the year the optium size of the bottomer section must be carefully selected in order not to overestimate its design power output. To achieve this goal a numerical optimization procedure has been implemented in the Matlab environment, based on the integration of a in house-developed calculation code with a commercial software for the thermodynamic design and off-design analysis of complex energy systems (Thermoflex). Thus the optimal ORC design power size is identified in the most generic scenario, in terms of compressors load profile, installation site conditions (i.e. ambient conditions and carbon tax value) and gas turbine models used as drivers. Two different objective functions are defined aiming at maximize the CO2 savings or the net present value. Different case studies are shown and discussed to prove the potential of the developed code. The comparison among the case studies highlights, chiefly, the influence of yearly mechanical drivers profile, part-load control strategy applied and carbon tax value on the ORC techno-economic feasibility.
{"title":"Optimum Size of ORC Cycles for Waste Heat Recovery in Natural Gas Compressor Stations","authors":"L. Branchini, M. A. Ancona, M. Bianchi, A. D. Pascale, F. Melino, A. Peretto, S. Ottaviano, N. Torricelli, D. Archetti, N. Rossetti, T. Ferrari","doi":"10.1115/gt2019-90009","DOIUrl":"https://doi.org/10.1115/gt2019-90009","url":null,"abstract":"\u0000 The paper investigates the optimum size and potential economic, energetic and environmental benefits of ORC applications, as bottomer section in natural gas compressor stations. Since typical installations consist of multiple gas turbine units in mechanical drive arrangement, operated most of the time under part-load conditions, the economic feasibility of the ORC can become questionable even though the energetic advantage is indisputable. Depending on mechanical drivers profile during the year the optium size of the bottomer section must be carefully selected in order not to overestimate its design power output. To achieve this goal a numerical optimization procedure has been implemented in the Matlab environment, based on the integration of a in house-developed calculation code with a commercial software for the thermodynamic design and off-design analysis of complex energy systems (Thermoflex). Thus the optimal ORC design power size is identified in the most generic scenario, in terms of compressors load profile, installation site conditions (i.e. ambient conditions and carbon tax value) and gas turbine models used as drivers. Two different objective functions are defined aiming at maximize the CO2 savings or the net present value. Different case studies are shown and discussed to prove the potential of the developed code. The comparison among the case studies highlights, chiefly, the influence of yearly mechanical drivers profile, part-load control strategy applied and carbon tax value on the ORC techno-economic feasibility.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122664040","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}
L. Vesely, Václav Dostál, J. Kapat, Subith S. Vasu, Scott Martin
The development of new power generation technologies are necessary to meet growing energy demands and emission requirements. The supercritical carbon dioxide (S-CO2) cycle is one such technology; it has relatively high efficiency, potential to enable 100% carbon capture, and compact components. The S-CO2 cycle is adaptable to almost all of the existing power producing methods including fossil, solar, and nuclear technologies. However, it is known that the best combination of the operating conditions, equipment, working fluid and cycle layout determine the maximum achievable efficiency of a cycle. Impurities in the cycle have some effect on the S-CO2 power cycle as presented in our previous work. The effect of impurities is positive or negative and affects all components. The effect of mixture compositions on the techno-economic evaluation is important information for the global understanding of the effect of mixtures on the S-CO2 power cycle. This paper focuses on the techno-economic evaluation of a hypothetical power plant with the S-CO2 power cycle. Two cases are considered for techno-economic evaluation. The difference between these cases is in the heat source and the associated heat exchanger (PCHE and shell and tube heat exchanger). Cost estimation was performed for three indicators (the levelized cost of electricity, the internal rate of return, and the net present value), which are important for economic viability and the rate of return of the project.
{"title":"Techno-Economic Evaluation of the Effect of Impurities on the Performance of Supercritical CO2 Cycles","authors":"L. Vesely, Václav Dostál, J. Kapat, Subith S. Vasu, Scott Martin","doi":"10.1115/gt2019-90704","DOIUrl":"https://doi.org/10.1115/gt2019-90704","url":null,"abstract":"\u0000 The development of new power generation technologies are necessary to meet growing energy demands and emission requirements. The supercritical carbon dioxide (S-CO2) cycle is one such technology; it has relatively high efficiency, potential to enable 100% carbon capture, and compact components. The S-CO2 cycle is adaptable to almost all of the existing power producing methods including fossil, solar, and nuclear technologies. However, it is known that the best combination of the operating conditions, equipment, working fluid and cycle layout determine the maximum achievable efficiency of a cycle. Impurities in the cycle have some effect on the S-CO2 power cycle as presented in our previous work. The effect of impurities is positive or negative and affects all components. The effect of mixture compositions on the techno-economic evaluation is important information for the global understanding of the effect of mixtures on the S-CO2 power cycle. This paper focuses on the techno-economic evaluation of a hypothetical power plant with the S-CO2 power cycle. Two cases are considered for techno-economic evaluation. The difference between these cases is in the heat source and the associated heat exchanger (PCHE and shell and tube heat exchanger). Cost estimation was performed for three indicators (the levelized cost of electricity, the internal rate of return, and the net present value), which are important for economic viability and the rate of return of the project.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127387616","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}
Stefan D. Cich, J. Moore, M. Marshall, K. Hoopes, J. Mortzheim, D. Hofer
An enabling technology for a successful deployment of the sCO2 closed-loop recompression Brayton cycle is the development of a high temperature turbine not currently available in the marketplace. This turbine was developed under DOE funding for the STEP Pilot Plant development and represents a second generation design of the Sunshot turbine (Moore, et al., 2018). The lower thermal mass and increased power density of the sCO2 cycle, as compared to steam-based systems, enables the development of compact, high-efficiency power blocks that can respond quickly to transient environmental changes and frequent start-up/shut-down operations. The power density of the turbine is significantly greater than traditional steam turbines and is rivaled only by liquid rocket engine turbo pumps, such as those used on the Space Shuttle Main Engines. One key area that presents a design challenge is the radial inlet and exit collector to the axial turbine. Due to the high power density and overall small size of the machine, the available space for this inlet, collectors and transition regions is limited. This paper will take a detailed look at the space constraints and also the balance of aero performance and mechanical constraints in designing optimal flow paths that will improve the overall efficiency of the cycle.
成功部署sCO2闭环再压缩布雷顿循环的一项使能技术是开发一种目前市场上没有的高温涡轮机。该涡轮机是在美国能源部资助的STEP中试工厂开发下开发的，代表了Sunshot涡轮机的第二代设计(Moore, et al.， 2018)。与蒸汽系统相比，sCO2循环具有更低的热质量和更高的功率密度，能够开发出紧凑、高效的电源模块，能够快速响应瞬态环境变化和频繁的启动/关闭操作。涡轮的功率密度明显大于传统的蒸汽涡轮，只有航天飞机主发动机上使用的液体火箭发动机涡轮泵可以与之匹敌。提出设计挑战的一个关键区域是轴向涡轮的径向入口和出口集热器。由于高功率密度和机器的整体小尺寸，这个入口，收集器和过渡区域的可用空间是有限的。本文将详细介绍空间限制，以及在设计优化流动路径时如何平衡气动性能和机械约束，从而提高循环的整体效率。
{"title":"Radial Inlet and Exit Design for a 10 MWe sCO2 Axial Turbine","authors":"Stefan D. Cich, J. Moore, M. Marshall, K. Hoopes, J. Mortzheim, D. Hofer","doi":"10.1115/gt2019-90392","DOIUrl":"https://doi.org/10.1115/gt2019-90392","url":null,"abstract":"\u0000 An enabling technology for a successful deployment of the sCO2 closed-loop recompression Brayton cycle is the development of a high temperature turbine not currently available in the marketplace. This turbine was developed under DOE funding for the STEP Pilot Plant development and represents a second generation design of the Sunshot turbine (Moore, et al., 2018). The lower thermal mass and increased power density of the sCO2 cycle, as compared to steam-based systems, enables the development of compact, high-efficiency power blocks that can respond quickly to transient environmental changes and frequent start-up/shut-down operations. The power density of the turbine is significantly greater than traditional steam turbines and is rivaled only by liquid rocket engine turbo pumps, such as those used on the Space Shuttle Main Engines. One key area that presents a design challenge is the radial inlet and exit collector to the axial turbine. Due to the high power density and overall small size of the machine, the available space for this inlet, collectors and transition regions is limited. This paper will take a detailed look at the space constraints and also the balance of aero performance and mechanical constraints in designing optimal flow paths that will improve the overall efficiency of the cycle.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"2014 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127402585","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}
L. Manservigi, M. Venturini, G. Ceschini, G. Bechini, E. Losi
Sensor fault detection and classification is a key challenge for machine monitoring and diagnostics. To this purpose, a comprehensive approach for Detection, Classification and Integrated Diagnostics of Gas Turbine Sensors (named DCIDS), previously developed by the authors, is improved in this paper to detect and classify different fault classes. For a single sensor or redundant/correlated sensors, the improved diagnostic tool, called I-DCIDS, can identify seven classes of fault, i.e. out of range, stuck signal, dithering, standard deviation, trend coherence, spike and bias. Fault detection is performed by means of basic mathematical laws that require some user-defined input parameters, i.e. acceptability thresholds and windows of observation. This paper presents in detail the I-DCIDS methodology for sensor fault detection and classification. Moreover, this paper reports some examples of application of the methodology to simulated data to highlight its capability to detect sensor faults which can be commonly encountered in field applications.
{"title":"A General Diagnostic Methodology for Sensor Fault Detection, Classification and Overall Health State Assessment","authors":"L. Manservigi, M. Venturini, G. Ceschini, G. Bechini, E. Losi","doi":"10.1115/gt2019-90055","DOIUrl":"https://doi.org/10.1115/gt2019-90055","url":null,"abstract":"\u0000 Sensor fault detection and classification is a key challenge for machine monitoring and diagnostics. To this purpose, a comprehensive approach for Detection, Classification and Integrated Diagnostics of Gas Turbine Sensors (named DCIDS), previously developed by the authors, is improved in this paper to detect and classify different fault classes. For a single sensor or redundant/correlated sensors, the improved diagnostic tool, called I-DCIDS, can identify seven classes of fault, i.e. out of range, stuck signal, dithering, standard deviation, trend coherence, spike and bias. Fault detection is performed by means of basic mathematical laws that require some user-defined input parameters, i.e. acceptability thresholds and windows of observation.\u0000 This paper presents in detail the I-DCIDS methodology for sensor fault detection and classification. Moreover, this paper reports some examples of application of the methodology to simulated data to highlight its capability to detect sensor faults which can be commonly encountered in field applications.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131537357","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}
Lakshminarayanan Seshadri, S. Sathish, Pramod Kumar, G. Giri, A. Nassar, L. Moroz, R. Setty, P. Gopi, Adi Narayana Namburi
Indian Institute of Science, Bangalore in collaboration with Sandia National Labs has developed a 140kW (thermal) simple recuperated supercritical CO2 (s-CO2) test facility to enable power generation of up to net 20 kWe output using turbomachinery components. The primary intent of the test loop is to understand the design and operational aspects of an s-CO2 Brayton cycle for distributed power generation. This paper describes the development of suitable turbomachinery to be deployed in the test loop. Turbomachinery design study is primarily performed using a commercial design tool AxStream® for both design and off-design operating conditions with a maximum cycle temperature limit of 525°C and a pressure of 145 bar. Present design considers a decoupled turbine and compressor driven independently by an electrical motor and a generator pair. This arrangement provides flexibility to independently assess compressor and turbine prototypes and also helps establish stable operation of the s-CO2 Brayton test loop. A range of single stage compressor and turbine geometries are independently evaluated considering un-coupled shafts and appropriate loss models using the above boundary conditions. Specific geometries are filtered based on total-to-total efficiency for a given shaft speed. The speed of the turbo-machinery is restricted to 40,000 rpm to enable independent testing and characterization using direct drive high-speed Switched Reluctance (SRM) motor-generator pair that is being developed in-house for this purpose. The investigation reveals the absence of a suitable compressor and turbine geometry at desired operating speed, hence, to circumvent the problem of low blade heights in the preliminary impeller design at 40,000 rpm, the turbomachinery is designed for 65,000 rpm and the off-design condition is taken for study.
{"title":"Design of 20 kW Turbomachinery for Closed Loop Supercritical Carbon Dioxide Brayton Test Loop Facility","authors":"Lakshminarayanan Seshadri, S. Sathish, Pramod Kumar, G. Giri, A. Nassar, L. Moroz, R. Setty, P. Gopi, Adi Narayana Namburi","doi":"10.1115/gt2019-90876","DOIUrl":"https://doi.org/10.1115/gt2019-90876","url":null,"abstract":"\u0000 Indian Institute of Science, Bangalore in collaboration with Sandia National Labs has developed a 140kW (thermal) simple recuperated supercritical CO2 (s-CO2) test facility to enable power generation of up to net 20 kWe output using turbomachinery components. The primary intent of the test loop is to understand the design and operational aspects of an s-CO2 Brayton cycle for distributed power generation. This paper describes the development of suitable turbomachinery to be deployed in the test loop. Turbomachinery design study is primarily performed using a commercial design tool AxStream® for both design and off-design operating conditions with a maximum cycle temperature limit of 525°C and a pressure of 145 bar. Present design considers a decoupled turbine and compressor driven independently by an electrical motor and a generator pair. This arrangement provides flexibility to independently assess compressor and turbine prototypes and also helps establish stable operation of the s-CO2 Brayton test loop. A range of single stage compressor and turbine geometries are independently evaluated considering un-coupled shafts and appropriate loss models using the above boundary conditions. Specific geometries are filtered based on total-to-total efficiency for a given shaft speed. The speed of the turbo-machinery is restricted to 40,000 rpm to enable independent testing and characterization using direct drive high-speed Switched Reluctance (SRM) motor-generator pair that is being developed in-house for this purpose. The investigation reveals the absence of a suitable compressor and turbine geometry at desired operating speed, hence, to circumvent the problem of low blade heights in the preliminary impeller design at 40,000 rpm, the turbomachinery is designed for 65,000 rpm and the off-design condition is taken for study.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"182 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134099073","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. Jauregui, Diego Cárdenas, Luis Morales, M. Martinez, J. Basaldua
The dynamic behavior of a wind turbine comprises three major parts: the external torque produced by the wind, the mechanical elements and the grid. For the aerodynamic response, there is three type of models: constant aerodynamic torque for Type I and Type IV turbines, a pseudo aerodynamic model for Type I and II, and linearized aerodynamic model for Type III. The drivetrain has been model either as a single-mass shaft model or as a double-mass shaft model. Most of the dynamic models of wind turbines consider the wind torque only as a function of the wind velocity, and they neglect the vibrations of the blades as an excitation torque. Therefore, a dynamic model that includes the aerodynamic power, the torque produced by the deflection of the blades, the vortex-induced vibrations of the blades and the torque caused by the eccentricity of the center of mass represents the excitation torque. The dynamic model of the wind turbine is a multibody dynamic model with six degrees of freedom. The blades are represented as a two lumped-masses, the torsional response of the main rotor is described as a single torsional mass, which is connected to the electric generator by a gearbox. The gearbox is represented as a double-shaft model, and the gear mesh is simulated with a nonlinear torsional stiffness. The generator is described as another torsional mass. The torque produced by the wind is calculated using QBlade for different pitch angles. The dynamic parameters of the blade were determined experimentally, and it was found that the blade has only two dominant vibration modes. For this reason, the blades were modeled as two lumped-masses. It was found that the vortex-induced vibrations modify the torsional vibrations of the generator and they are an extra source of perturbations for the electric generation, and they depend on the wind velocity and the pitch angle.
{"title":"The Effect of Blade Deflections on the Torsional Dynamic of a Wind Turbine","authors":"J. Jauregui, Diego Cárdenas, Luis Morales, M. Martinez, J. Basaldua","doi":"10.1115/gt2019-91046","DOIUrl":"https://doi.org/10.1115/gt2019-91046","url":null,"abstract":"\u0000 The dynamic behavior of a wind turbine comprises three major parts: the external torque produced by the wind, the mechanical elements and the grid. For the aerodynamic response, there is three type of models: constant aerodynamic torque for Type I and Type IV turbines, a pseudo aerodynamic model for Type I and II, and linearized aerodynamic model for Type III. The drivetrain has been model either as a single-mass shaft model or as a double-mass shaft model. Most of the dynamic models of wind turbines consider the wind torque only as a function of the wind velocity, and they neglect the vibrations of the blades as an excitation torque. Therefore, a dynamic model that includes the aerodynamic power, the torque produced by the deflection of the blades, the vortex-induced vibrations of the blades and the torque caused by the eccentricity of the center of mass represents the excitation torque. The dynamic model of the wind turbine is a multibody dynamic model with six degrees of freedom. The blades are represented as a two lumped-masses, the torsional response of the main rotor is described as a single torsional mass, which is connected to the electric generator by a gearbox. The gearbox is represented as a double-shaft model, and the gear mesh is simulated with a nonlinear torsional stiffness. The generator is described as another torsional mass. The torque produced by the wind is calculated using QBlade for different pitch angles. The dynamic parameters of the blade were determined experimentally, and it was found that the blade has only two dominant vibration modes. For this reason, the blades were modeled as two lumped-masses. It was found that the vortex-induced vibrations modify the torsional vibrations of the generator and they are an extra source of perturbations for the electric generation, and they depend on the wind velocity and the pitch angle.","PeriodicalId":412490,"journal":{"name":"Volume 9: Oil and Gas Applications; Supercritical CO2 Power Cycles; Wind Energy","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115436314","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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