Pub Date : 2024-11-28DOI: 10.1016/j.cryogenics.2024.103994
J.S. Hansdah , P.M. Sarun , K. Asokan
We studied the effect of carbon (C) ion implantation on the microstructure and superconducting properties of bulk MgB2 prepared by the powder-in-sealed-tube (PIST) method. FESEM and TEM analysis indicate microstructural changes due to carbon ion implantation. DC magnetization measurements reveal a slight improvement of TC and small ΔTC values due to ion implantation. The JC(B) characteristics of implanted samples show a significant enhancement of JC compared with pristine MgB2 at 10 and 20 K. MgB2 samples implanted with 80 keV carbon ions with a dose of 2 × 1016 ions cm−2 show maximum enhancement in JC i.e., 2.07 × 105 A/cm2 at 5 T and 10 K. The flux pinning force density curves are theoretically analyzed using the Dew-Hughes model. The results reveal that significant enhancements in the flux pinning properties are contributed by the normal point defects caused by carbon ion implantation, which acts as a strong pinning center.
{"title":"Effect of carbon ion implantation on the superconducting properties of MgB2 bulks prepared by powder-in-sealed-tube method","authors":"J.S. Hansdah , P.M. Sarun , K. Asokan","doi":"10.1016/j.cryogenics.2024.103994","DOIUrl":"10.1016/j.cryogenics.2024.103994","url":null,"abstract":"<div><div>We studied the effect of carbon (C) ion implantation on the microstructure and superconducting properties of bulk MgB<sub>2</sub> prepared by the powder-in-sealed-tube (PIST) method. FESEM and TEM analysis indicate microstructural changes due to carbon ion implantation. DC magnetization measurements reveal a slight improvement of T<sub>C</sub> and small ΔT<sub>C</sub> values due to ion implantation. The J<sub>C</sub>(B) characteristics of implanted samples show a significant enhancement of J<sub>C</sub> compared with pristine MgB<sub>2</sub> at 10 and 20 K. MgB<sub>2</sub> samples implanted with 80 keV carbon ions with a dose of 2 × 10<sup>16</sup> ions cm<sup>−2</sup> show maximum enhancement in J<sub>C</sub> i.e., 2.07 × 10<sup>5</sup> A/cm<sup>2</sup> at 5 T and 10 K. The flux pinning force density curves are theoretically analyzed using the Dew-Hughes model. The results reveal that significant enhancements in the flux pinning properties are contributed by the normal point defects caused by carbon ion implantation, which acts as a strong pinning center.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"145 ","pages":"Article 103994"},"PeriodicalIF":1.8,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents a feasibility study of the Cryogenic Cooling and Cutting System (CCCS), an embrittlement-based technique for offshore wind monopile foundations. The CCCS employs cryogenic treatment of the monopile wall surface to significantly reduce its impact energy absorption capability significantly, aiming to achieve shorter overall cutting time than conventional cutting techniques. Through numerical analysis, the performance of CCCS is assessed and compared with the Abrasive Water Jet (AWJ) technique, revealing that CCCS offers up to 46.8 times faster cutting speeds and reduces cutting times by 87.1 % – 97.9 % across various monopile diameters and wall thicknesses. These improvements indicate the potential for substantial reductions in the cost and emissions associated with Offshore Wind Farm (OWF) decommissioning. Specifically, the application of CCCS could reduce the total foundation removal operation time by 28 %, resulting in 23 % savings in vessel leasing costs for a real-world OWF decommissioning project. Our findings suggest that the proposed CCCS technique enhances cutting efficiency and contributes significantly to the economic and environmental sustainability of OWF decommissioning. This study aims to demonstrate the CCCS technique’s unique advantages over conventional methods, such as AWJ, by significantly reducing both cutting times and environmental impact, thereby enhancing the sustainability and cost-effectiveness of offshore wind farm decommissioning.
{"title":"A study on the potential of cryogenic cooling and cutting technique in reducing the decommissioning cost of offshore monopiles","authors":"Kenneth Bisgaard Christensen , Alireza Maheri , M.Amir Siddiq , Shahin Jalili","doi":"10.1016/j.cryogenics.2024.103991","DOIUrl":"10.1016/j.cryogenics.2024.103991","url":null,"abstract":"<div><div>This paper presents a feasibility study of the Cryogenic Cooling and Cutting System (CCCS), an embrittlement-based technique for offshore wind monopile foundations. The CCCS employs cryogenic treatment of the monopile wall surface to significantly reduce its impact energy absorption capability significantly, aiming to achieve shorter overall cutting time than conventional cutting techniques. Through numerical analysis, the performance of CCCS is assessed and compared with the Abrasive Water Jet (AWJ) technique, revealing that CCCS offers up to 46.8 times faster cutting speeds and reduces cutting times by 87.1 % – 97.9 % across various monopile diameters and wall thicknesses. These improvements indicate the potential for substantial reductions in the cost and emissions associated with Offshore Wind Farm (OWF) decommissioning. Specifically, the application of CCCS could reduce the total foundation removal operation time by 28 %, resulting in 23 % savings in vessel leasing costs for a real-world OWF decommissioning project. Our findings suggest that the proposed CCCS technique enhances cutting efficiency and contributes significantly to the economic and environmental sustainability of OWF decommissioning. This study aims to demonstrate the CCCS technique’s unique advantages over conventional methods, such as AWJ, by significantly reducing both cutting times and environmental impact, thereby enhancing the sustainability and cost-effectiveness of offshore wind farm decommissioning.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"145 ","pages":"Article 103991"},"PeriodicalIF":1.8,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-23DOI: 10.1016/j.cryogenics.2024.103993
Yanan Li , Xiufang Liu , Qingshuo Miao , Jiajun Chen , Fuhao Zhong , Mian Zheng , Yu Hou
Liquid nitrogen droplets impacting superheated wall is an essential phenomenon in cryogenic phase-change spray cooling. In this study, the Volume of Fluid (VOF) method was used to develop a numerical model to investigate the kinetic and thermodynamic characteristics of liquid nitrogen droplets impacting superheated wall. The experiment for the impact of liquid nitrogen droplets was conducted to validate the simulation. The findings indicate that liquid nitrogen droplets impacting superheated wall exhibit three boiling regimes: contact boiling, transition boiling, and film boiling. During contact boiling, as We increases, droplets undergo three modes sequentially: spreading, forming fingering-like structures, and fragmentation. During transition boiling and film boiling, as We increases, droplets exhibit spreading, splashing, and fragmentation. Increasing the wall temperature leads to the formation of vapor pockets and vapor film, which results in deteriorated heat transfer at the solid–liquid contact area, and meanwhile reducing the extent of droplet spreading. Increasing We promotes droplet spreading, reducing vapor pockets and vapor film thickness, increasing wetting area, and postpones the onset of heat transfer deterioration. Increasing the wall temperature and We both lead to a higher decreasing rate of liquid volume of droplet which indicates an intensified vaporization rate. The larger the contact angle of the wall, the less the droplet spreads, and the lower the heat transfer between the droplets and the wall.
液氮液滴撞击过热壁是低温相变喷雾冷却中的一个基本现象。本研究采用流体体积法（VOF）建立了一个数值模型，以研究液氮液滴撞击过热壁的动力学和热力学特性。为验证模拟结果，还进行了液氮液滴撞击实验。研究结果表明，液氮液滴撞击过热壁面会出现三种沸腾状态：接触沸腾、过渡沸腾和薄膜沸腾。在接触沸腾过程中，随着 We 的增加，液氮液滴会依次经历三种模式：扩散、形成指状结构和破碎。在过渡沸腾和薄膜沸腾过程中，随着 We 的增加，液滴会出现扩散、飞溅和破碎。壁温升高会形成汽穴和汽膜，导致固液接触区的传热恶化，同时降低液滴扩散的程度。增加 We 会促进液滴扩散，减少汽穴和汽膜厚度，增加润湿面积，推迟传热恶化的发生。壁温和 We 的增加都会导致液滴液体体积的下降率增加，这表明汽化速度加快。壁面接触角越大，液滴扩散越小，液滴与壁面之间的传热越低。
{"title":"Simulation and experimental investigation on kinetic and thermodynamic characteristics of liquid nitrogen droplets impacting superheated wall","authors":"Yanan Li , Xiufang Liu , Qingshuo Miao , Jiajun Chen , Fuhao Zhong , Mian Zheng , Yu Hou","doi":"10.1016/j.cryogenics.2024.103993","DOIUrl":"10.1016/j.cryogenics.2024.103993","url":null,"abstract":"<div><div>Liquid nitrogen droplets impacting superheated wall is an essential phenomenon in cryogenic phase-change spray cooling. In this study, the Volume of Fluid (VOF) method was used to develop a numerical model to investigate the kinetic and thermodynamic characteristics of liquid nitrogen droplets impacting superheated wall. The experiment for the impact of liquid nitrogen droplets was conducted to validate the simulation. The findings indicate that liquid nitrogen droplets impacting superheated wall exhibit three boiling regimes: contact boiling, transition boiling, and film boiling. During contact boiling, as <em>We</em> increases, droplets undergo three modes sequentially: spreading, forming fingering-like structures, and fragmentation. During transition boiling and film boiling, as <em>We</em> increases, droplets exhibit spreading, splashing, and fragmentation. Increasing the wall temperature leads to the formation of vapor pockets and vapor film, which results in deteriorated heat transfer at the solid–liquid contact area, and meanwhile reducing the extent of droplet spreading. Increasing <em>We</em> promotes droplet spreading, reducing vapor pockets and vapor film thickness, increasing wetting area, and postpones the onset of heat transfer deterioration. Increasing the wall temperature and <em>We</em> both lead to a higher decreasing rate of liquid volume of droplet which indicates an intensified vaporization rate. The larger the contact angle of the wall, the less the droplet spreads, and the lower the heat transfer between the droplets and the wall.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"145 ","pages":"Article 103993"},"PeriodicalIF":1.8,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-12DOI: 10.1016/j.cryogenics.2024.103983
Benjamin Straiton , Matthew Charleston , Qussai Marashdeh , Jonathan Harrison , Matthew Reppa
Mass flow rate is a critical measurement parameter when designing cryogenic hydrogen fluid systems. It is important in custody transfer applications for calculating financial obligations, fundamental fluid property research/modeling, and fluid system design applications to optimize chill down performance, maintain thermal equilibriums, and provide feedback control for pumps and valves. However, due to the large temperature differential between cryogenic fluids and the environment, there is often multiphase flow during system chilldown and steady state operation. Current available cryogenic flow measurement techniques are not equipped to deal with the complex multiphase flow inherent in cryogenic fluid systems, resulting in significant measurement errors. This mass flow measurement inaccuracy can cause financial loss, system instability, and even component failure, resulting in a strong market demand for a multiphase cryogenic mass flow meter to optimize and control sophisticated and costly cryogenic systems. This paper presents a solution in the form of a novel capacitance-based technique for measuring the multiphase mass flow rate of cryogenic hydrogen in a terrestrial environment. The device was calibrated and tested on a ½” tube multiphase hydrogen flow loop at a cryogenic hydrogen test facility. An error of ± 2 % full scale was achieved across a range of flow conditions, including transient and steady states.
{"title":"Capacitance-based mass flow rate measurement of two-phase hydrogen in a 0.5 in. tube","authors":"Benjamin Straiton , Matthew Charleston , Qussai Marashdeh , Jonathan Harrison , Matthew Reppa","doi":"10.1016/j.cryogenics.2024.103983","DOIUrl":"10.1016/j.cryogenics.2024.103983","url":null,"abstract":"<div><div>Mass flow rate is a critical measurement parameter when designing cryogenic hydrogen fluid systems. It is important in custody transfer applications for calculating financial obligations, fundamental fluid property research/modeling, and fluid system design applications to optimize chill down performance, maintain thermal equilibriums, and provide feedback control for pumps and valves. However, due to the large temperature differential between cryogenic fluids and the environment, there is often multiphase flow during system chilldown and steady state operation. Current available cryogenic flow measurement techniques are not equipped to deal with the complex multiphase flow inherent in cryogenic fluid systems, resulting in significant measurement errors. This mass flow measurement inaccuracy can cause financial loss, system instability, and even component failure, resulting in a strong market demand for a multiphase cryogenic mass flow meter to optimize and control sophisticated and costly cryogenic systems. This paper presents a solution in the form of a novel capacitance-based technique for measuring the multiphase mass flow rate of cryogenic hydrogen in a terrestrial environment. The device was calibrated and tested on a ½” tube multiphase hydrogen flow loop at a cryogenic hydrogen test facility. An error of ± 2 % full scale was achieved across a range of flow conditions, including transient and steady states.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"144 ","pages":"Article 103983"},"PeriodicalIF":1.8,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-09DOI: 10.1016/j.cryogenics.2024.103982
Mingsheng Tang , Zhouhang Hu , Liubiao Chen , Yongheng Wu , Jianhua Xiao , Qingqing Yuan , Huiming Zou
This study proposes a new type of oil-free linear compressor with a magnetic resonance spring, which uses a magnetic resonance spring to provide restoring force and adopts gas-lubricated bearings to provide support force for the piston. The frequency characteristics of the compressor, including magnetic spring stiffness, gas spring stiffness, and resonance frequency, are studied through experiments and theoretical analysis. The magnetic spring stiffness is 31403.31 N/m of the design compressor. Hooke’s law and Fourier decomposition are employed for the gas spring stiffness measuring the compression pressure gauged. Meanwhile, the gas spring stiffness is also obtained from the amplitude-frequency characteristic of the compressor by the back stepping technique with an electric parameter frequency scan. The experimental results demonstrate that the three measurement methods have good consistency in measuring the gas spring stiffness. The equivalent gas spring stiffness measured using the three methods and theoretical model are 72600.92 N/m, 71275.84 N/m, 71967.15 N/m, and 71929.25 N/m at 3 MPa charged pressure measured respectively. In addition, the refrigeration performance of the pulse tube cryocooler driven by the compressor is tested and the lowest temperature obtained in the cold end is 46.3 K under different charge pressure. Furthermore, an optimal frequency exists that enhances the refrigeration performance of the pulse tube cryocooler, and this optimal frequency remains constant regardless of changes in the charge pressure.
{"title":"Investigation of the performance of oil-free linear compressor with magnetic resonance spring for pulse tube cryocooler","authors":"Mingsheng Tang , Zhouhang Hu , Liubiao Chen , Yongheng Wu , Jianhua Xiao , Qingqing Yuan , Huiming Zou","doi":"10.1016/j.cryogenics.2024.103982","DOIUrl":"10.1016/j.cryogenics.2024.103982","url":null,"abstract":"<div><div>This study proposes a new type of oil-free linear compressor with a magnetic resonance spring, which uses a magnetic resonance spring to provide restoring force and adopts gas-lubricated bearings to provide support force for the piston. The frequency characteristics of the compressor, including magnetic spring stiffness, gas spring stiffness, and resonance frequency, are studied through experiments and theoretical analysis. The magnetic spring stiffness is 31403.31 N/m of the design compressor. Hooke’s law and Fourier decomposition are employed for the gas spring stiffness measuring the compression pressure gauged. Meanwhile, the gas spring stiffness is also obtained from the amplitude-frequency characteristic of the compressor by the back stepping technique with an electric parameter frequency scan. The experimental results demonstrate that the three measurement methods have good consistency in measuring the gas spring stiffness. The equivalent gas spring stiffness measured using the three methods and theoretical model are 72600.92 N/m, 71275.84 N/m, 71967.15 N/m, and 71929.25 N/m at 3 MPa charged pressure measured respectively. In addition, the refrigeration performance of the pulse tube cryocooler driven by the compressor is tested and the lowest temperature obtained in the cold end is 46.3 K under different charge pressure. Furthermore, an optimal frequency exists that enhances the refrigeration performance of the pulse tube cryocooler, and this optimal frequency remains constant regardless of changes in the charge pressure.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"144 ","pages":"Article 103982"},"PeriodicalIF":1.8,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1016/j.cryogenics.2024.103980
Enze Ma , Yulong Li , Yuan Gao
The hydrogen-powered aviation hybrid technology is one of the important directions of the development of electrical aircraft propulsion. Superconducting motors (SCMs) are the core components of a hydrogen-powered aircraft due to their high power-to-weight ratio. Among SCMs, partial SCMs with superconducting armature windings and permanent magnets (SC-PMMs) are the research front and hotspots. This study focuses on the key issue of cooling the superconducting (SC) coils of SC-PMMs. The advantages and disadvantages of three cooling structures, namely core conduction cooling, coil immersion cooling, and core and coil immersion cooling, are compared. The temperature of the SC coils in different cooling structures is simulated and analyzed in detail. The obtained results show that the temperature of the coils in the core and coil immersion cooling structure is not much different from that in the coil immersion cooling structure, with a temperature difference of about 1.5 K only. However, the implementation of the core and coil immersion cooling structure is much easier. Therefore, an SC-PMM prototype is developed using it as the cooling structure, and the temperature change in the prototype under different operating conditions is investigated experimentally. The obtained results show that the final stable temperature during the cooling process is 76.8 K, and the coil on the top is more likely to quench than that at the bottom. The maximum frequency and maximum current at which the prototype can operate stably for a long time are 200 Hz and 49 A, respectively. This study verifies the effectiveness of the core and coil immersion cooling structure, obtains the quench prone area in SC-PMMs, and lays the foundation for the development of high-performance and highly reliable SCMs.
{"title":"Analysis and Verification of cooling structure of superconducting motors for electrical aircraft propulsion","authors":"Enze Ma , Yulong Li , Yuan Gao","doi":"10.1016/j.cryogenics.2024.103980","DOIUrl":"10.1016/j.cryogenics.2024.103980","url":null,"abstract":"<div><div>The hydrogen-powered aviation hybrid technology is one of the important directions of the development of electrical aircraft propulsion. Superconducting motors (SCMs) are the core components of a hydrogen-powered aircraft due to their high power-to-weight ratio. Among SCMs, partial SCMs with superconducting armature windings and permanent magnets (SC-PMMs) are the research front and hotspots. This study focuses on the key issue of cooling the superconducting (SC) coils of SC-PMMs. The advantages and disadvantages of three cooling structures, namely core conduction cooling, coil immersion cooling, and core and coil immersion cooling, are compared. The temperature of the SC coils in different cooling structures is simulated and analyzed in detail. The obtained results show that the temperature of the coils in the core and coil immersion cooling structure is not much different from that in the coil immersion cooling structure, with a temperature difference of about 1.5 K only. However, the implementation of the core and coil immersion cooling structure is much easier. Therefore, an SC-PMM prototype is developed using it as the cooling structure, and the temperature change in the prototype under different operating conditions is investigated experimentally. The obtained results show that the final stable temperature during the cooling process is 76.8 K, and the coil on the top is more likely to quench than that at the bottom. The maximum frequency and maximum current at which the prototype can operate stably for a long time are 200 Hz and 49 A, respectively. This study verifies the effectiveness of the core and coil immersion cooling structure, obtains the quench prone area in SC-PMMs, and lays the foundation for the development of high-performance and highly reliable SCMs.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"144 ","pages":"Article 103980"},"PeriodicalIF":1.8,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1016/j.cryogenics.2024.103981
Zuoguang Li , Zhan Zhang , Jiulong Zhang , Yuhu Bu , Donghu Wang , Guanyu Xiao , Huan Jin , Jinggang Qin , Chao Zhou
The second generation of high temperature superconductivity (HTS) is one of the candidate materials for future superconducting cables (such as CORC), CICC conductors and high field magnets due to its high current carrying performance and excellent mechanical strength. Currently, it has been demonstrated that the utilization of REBCO multi-filamentary tapes in the fabrication of CORC cables can further reduce AC losses. This study involved the preparation of various types of REBCO multi-filamentary tapes through reel-to-reel ultraviolet picosecond laser cutting technology, as well as the manual winding of multiple single-layer CORC cable samples. This work focused on the impact of core diameter on the current-carrying performance of REBCO multi-filamentary tapes under self-field conditions at 77 K. The results indicate that the critical current (IC) of REBCO multi-filamentary tapes decreases as the core diameter decreases. Furthermore, the decrease in IC becomes more significant with an increasing number of cores. When the cable core diameter is 4.6 mm, the critical current of the 3-filament tape is 180.49 A with an n-value of 24.84, which is only a 3.1 % recession compared to the critical current of the commercialized tape. The conclusion of this paper will provide a certain data reference for the subsequent selection of CORC cable core size prepared by REBCO multi-filamentary tapes.
第二代高温超导（HTS）具有高载流性能和出色的机械强度，是未来超导电缆（如 CORC）、CICC 导体和高磁场磁体的候选材料之一。目前，已有研究表明，在制造 CORC 电缆时使用 REBCO 多丝带可进一步降低交流损耗。本研究通过卷对卷紫外皮秒激光切割技术制备了各种类型的 REBCO 多丝带，并手工卷绕了多个单层 CORC 电缆样品。这项工作的重点是在 77 K 的自场条件下，研究芯线直径对 REBCO 多丝带载流性能的影响。结果表明，REBCO 多丝带的临界电流 (IC) 会随着线芯直径的减小而减小。此外，随着缆芯数量的增加，临界电流（IC）的下降幅度也越来越大。当缆芯直径为 4.6 mm 时，3 芯胶带的临界电流为 180.49 A，n 值为 24.84，与商业化胶带的临界电流相比仅下降了 3.1%。本文的结论将为后续选择由 REBCO 多丝带制备的 CORC 电缆芯尺寸提供一定的数据参考。
{"title":"Effect of different core diameters on the current-carrying performance of CORC cables with REBCO multi-filamentary tapes","authors":"Zuoguang Li , Zhan Zhang , Jiulong Zhang , Yuhu Bu , Donghu Wang , Guanyu Xiao , Huan Jin , Jinggang Qin , Chao Zhou","doi":"10.1016/j.cryogenics.2024.103981","DOIUrl":"10.1016/j.cryogenics.2024.103981","url":null,"abstract":"<div><div>The second generation of high temperature superconductivity (HTS) is one of the candidate materials for future superconducting cables (such as CORC), CICC conductors and high field magnets due to its high current carrying performance and excellent mechanical strength. Currently, it has been demonstrated that the utilization of REBCO multi-filamentary tapes in the fabrication of CORC cables can further reduce AC losses. This study involved the preparation of various types of REBCO multi-filamentary tapes through reel-to-reel ultraviolet picosecond laser cutting technology, as well as the manual winding of multiple single-layer CORC cable samples. This work focused on the impact of core diameter on the current-carrying performance of REBCO multi-filamentary tapes under self-field conditions at 77 K. The results indicate that the critical current (<em>I<sub>C</sub></em>) of REBCO multi-filamentary tapes decreases as the core diameter decreases. Furthermore, the decrease in <em>I<sub>C</sub></em> becomes more significant with an increasing number of cores. When the cable core diameter is 4.6 mm, the critical current of the 3-filament tape is 180.49 A with an <em>n</em>-value of 24.84, which is only a 3.1 % recession compared to the critical current of the commercialized tape. The conclusion of this paper will provide a certain data reference for the subsequent selection of CORC cable core size prepared by REBCO multi-filamentary tapes.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"144 ","pages":"Article 103981"},"PeriodicalIF":1.8,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1016/j.cryogenics.2024.103979
Longyu Yang , Xin Zhang , Yu Yan , Shengnan Meng , Bingcheng Wang , Zheng Cui , Cheng Shao , Lin Cheng
Micro-orifice is a critical component in cryogenic refrigeration systems that determines the mass flow rate and total cooling power. However, a sophisticated model to accurately predict mass flow rates, especially for helium (He) below its maximum inversion temperature, where its properties differ significantly from those of an ideal gas, is lacking. This study investigated the mass flow characteristics and entropy production of 4He gas flow in micro-orifices using computational fluid dynamics (CFD) simulations. Various conditions, including upstream temperatures, upstream pressures, and downstream pressures, were analyzed and compared with the predictions from the Maytal model. Our results show that entropy production due to velocity and temperature gradient fluctuations plays a significant role in determining flow rates. Under upstream conditions of 15 K, 0.7 MPa, and a 20 μm diameter, the entropy increase coefficient (δ) is 0.083. Neglecting this entropy production leads to an overprediction of the mass flux by 39.8 %. A modified Maytal model that accounts for entropy production yields predictions in better agreement with CFD simulations, with a maximum deviation of less than 6.3 %. This work highlights the critical role of entropy production in 4He gas flow through micro-orifices and offers guidance for selecting micro-orifices in cryogenic applications.
{"title":"Mass flow and entropy production in choked 4He gas flow through micro-orifices","authors":"Longyu Yang , Xin Zhang , Yu Yan , Shengnan Meng , Bingcheng Wang , Zheng Cui , Cheng Shao , Lin Cheng","doi":"10.1016/j.cryogenics.2024.103979","DOIUrl":"10.1016/j.cryogenics.2024.103979","url":null,"abstract":"<div><div>Micro-orifice is a critical component in cryogenic refrigeration systems that determines the mass flow rate and total cooling power. However, a sophisticated model to accurately predict mass flow rates, especially for helium (He) below its maximum inversion temperature, where its properties differ significantly from those of an ideal gas, is lacking. This study investigated the mass flow characteristics and entropy production of <sup>4</sup>He gas flow in micro-orifices using computational fluid dynamics (CFD) simulations. Various conditions, including upstream temperatures, upstream pressures, and downstream pressures, were analyzed and compared with the predictions from the Maytal model. Our results show that entropy production due to velocity and temperature gradient fluctuations plays a significant role in determining flow rates. Under upstream conditions of 15 K, 0.7 MPa, and a 20 μm diameter, the entropy increase coefficient (<em>δ</em>) is 0.083. Neglecting this entropy production leads to an overprediction of the mass flux by 39.8 %. A modified Maytal model that accounts for entropy production yields predictions in better agreement with CFD simulations, with a maximum deviation of less than 6.3 %. This work highlights the critical role of entropy production in <sup>4</sup>He gas flow through micro-orifices and offers guidance for selecting micro-orifices in cryogenic applications.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"144 ","pages":"Article 103979"},"PeriodicalIF":1.8,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-05DOI: 10.1016/j.cryogenics.2024.103978
Damien Furfaro , Jacek Kosek , Andrey Ovcharov , Tyge Schioler , Rossella Rotella , Tim Luce
A new software is being developed for plasma pulse scenario validation of the ITER magnet system behaviour and prediction of the margin to quench in superconductors. The principal idea behind this project has been to develop a software tool for the thermo-hydraulic simulation of superconducting magnets that is able to simulate different operations scenarios for the magnets at least an order of magnitude faster than real time. To achieve this level of performance, a tight coupling between the Cable-In-Conduit-Conductors and the structure of the magnet is performed. All the equations for the flow and heat conduction parts of the global model are put in a single sparse system that is integrated in time. Such tight coupling in combination with implicit time stepping allows much longer time steps whilst keeping high accuracy of the solution. The code named REIMS (Riemann Explicit Implicit Magnet Simulator) is still under development. Both central solenoid (CS) and toroidal field (TF) ITER magnets are available at this stage. The development of the different intermediate steps that led to the current version of the code required verification/validation against exact solutions, experimental data and/or comparisons with existing codes. In the same way, results obtained with REIMS for the simulation of both CS and TF loops after application of a short plasma pulse scenario have been compared to results from existing reference codes, showing a good agreement.
{"title":"A new fast and robust thermo-hydraulic code for ITER superconducting magnet simulation","authors":"Damien Furfaro , Jacek Kosek , Andrey Ovcharov , Tyge Schioler , Rossella Rotella , Tim Luce","doi":"10.1016/j.cryogenics.2024.103978","DOIUrl":"10.1016/j.cryogenics.2024.103978","url":null,"abstract":"<div><div>A new software is being developed for plasma pulse scenario validation of the ITER magnet system behaviour and prediction of the margin to quench in superconductors. The principal idea behind this project has been to develop a software tool for the thermo-hydraulic simulation of superconducting magnets that is able to simulate different operations scenarios for the magnets at least an order of magnitude faster than real time. To achieve this level of performance, a tight coupling between the Cable-In-Conduit-Conductors and the structure of the magnet is performed. All the equations for the flow and heat conduction parts of the global model are put in a single sparse system that is integrated in time. Such tight coupling in combination with implicit time stepping allows much longer time steps whilst keeping high accuracy of the solution. The code named REIMS (Riemann Explicit Implicit Magnet Simulator) is still under development. Both central solenoid (CS) and toroidal field (TF) ITER magnets are available at this stage. The development of the different intermediate steps that led to the current version of the code required verification/validation against exact solutions, experimental data and/or comparisons with existing codes. In the same way, results obtained with REIMS for the simulation of both CS and TF loops after application of a short plasma pulse scenario have been compared to results from existing reference codes, showing a good agreement.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"144 ","pages":"Article 103978"},"PeriodicalIF":1.8,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-05DOI: 10.1016/j.cryogenics.2024.103976
Jens Falter , Jack Schmidt , Xaver Herrmann , Bernd Schmidt , Dirk Dietzel , André Schirmeisen
Conventional operation of closed-cycle two-stage GM-type Pulse Tube Cryocoolers (PTCs) usually relies on utilizing the cooling power of both the 1 and the 2 stage. While the 1 stage is required to precool the 2 stage to reach the lowest accessible temperature below 4K, it usually also provides enough cooling power to cool additional cryostat elements such as radiation shieldings. However, current applications in quantum physics have highlighted the need to additionally access heat sinks with intermediate temperatures and cooling powers, e.g. for cooling of superconducting wires. Here we will demonstrate a cooler configuration, where a third cooling stage is incorporated into the 2 stage regenerator. This third intermediate cooling stage allows to extract 4-5 W of cooling power at temperatures between 8 K and 9 K for a standard two-stage PTC with a cooling capacity of 1.6 W at 4.2 K. Most importantly, this approach does not reduce the performance of the main stage but the added intermediate regenerator stage instead allows to tap into hidden cooling power of the PTC.
{"title":"Two stage pulse tube cryocooler with intermediate heat exchanger for accessing regenerator cooling capacity","authors":"Jens Falter , Jack Schmidt , Xaver Herrmann , Bernd Schmidt , Dirk Dietzel , André Schirmeisen","doi":"10.1016/j.cryogenics.2024.103976","DOIUrl":"10.1016/j.cryogenics.2024.103976","url":null,"abstract":"<div><div>Conventional operation of closed-cycle two-stage GM-type Pulse Tube Cryocoolers (PTCs) usually relies on utilizing the cooling power of both the 1<span><math><msup><mrow></mrow><mrow><mi>s</mi><mi>t</mi></mrow></msup></math></span> and the 2<span><math><msup><mrow></mrow><mrow><mi>n</mi><mi>d</mi></mrow></msup></math></span> stage. While the 1<span><math><msup><mrow></mrow><mrow><mi>s</mi><mi>t</mi></mrow></msup></math></span> stage is required to precool the 2<span><math><msup><mrow></mrow><mrow><mi>n</mi><mi>d</mi></mrow></msup></math></span> stage to reach the lowest accessible temperature below 4K, it usually also provides enough cooling power to cool additional cryostat elements such as radiation shieldings. However, current applications in quantum physics have highlighted the need to additionally access heat sinks with intermediate temperatures and cooling powers, e.g. for cooling of superconducting wires. Here we will demonstrate a cooler configuration, where a third cooling stage is incorporated into the 2<span><math><msup><mrow></mrow><mrow><mi>n</mi><mi>d</mi></mrow></msup></math></span> stage regenerator. This third intermediate cooling stage allows to extract 4-5 W of cooling power at temperatures between 8 K and 9 K for a standard two-stage PTC with a cooling capacity of 1.6 W at 4.2 K. Most importantly, this approach does not reduce the performance of the main stage but the added intermediate regenerator stage instead allows to tap into hidden cooling power of the PTC.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"144 ","pages":"Article 103976"},"PeriodicalIF":1.8,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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