Cryogenics最新文献

{"title":"Experiments and simulations related to the sudden application of a heat pulse onto a supercritical helium flow","authors":"S. Shoala ,&nbsp;E. Ercolani ,&nbsp;F. Ayela ,&nbsp;J.M. Poncet","doi":"10.1016/j.cryogenics.2025.104029","DOIUrl":"10.1016/j.cryogenics.2025.104029","url":null,"abstract":"<div><div>Vacuum loss is a major accidental scenario in cryogenic facilities that use vacuum for thermal insulation from the surrounding environment. An experimental facility, called HELIOS, has been set up to study vacuum loss around a cryoline in which supercritical helium is flowing. Before carrying out real vacuum loss experiments, a preliminary test campaign was performed using an electrical test section inserted into a cryogenic loop within the HELIOS facility, at the exact location of the future vacuum loss test section. The electrical section is equipped with an electrical heater that was used to simulate the heat pulse that would be experienced by the supercritical helium flow in the event of a real vacuum loss accident. The consequences of the abruptly applied heat pulse have been studied, both in real and simulated conditions. The main objectives of this first experimental campaign are multiple: to assess the design of the HELIOS facility, verify the accuracy of the heat flux measurement methods, and use the results of the experimental test campaigns to improve the qualification of the thermal hydraulic code employed to size the experimental setup. The simulation was based on the thermal–hydraulic code CATHARE 3 and includes two-phases cryogenic flows. Thermal-hydraulic parameters of the supercritical helium flow as pressure, temperature and mass flow rate, have been recorded for several heat loads running from 0.45 kW to 2.5 kW, with durations of up to 2 min. Heat transfer in the supercritical loop and the liquid helium bath, as well as corresponding energy balances, have been calculated. The resulting estimations of the heat applied to the test section correspond with an excellent accuracy to the real thermal loads. For a heat flux of 1.35 kW, the data were also simulated with the CATHARE 3 code. The results of the simulation match the measured and calculated data with high accuracy. This preliminary work and its associated conclusions provide a firm basis for forthcoming experiments, which will be devoted to the study of heat transfer following a real breakdown of the insulating vacuum in the supercritical helium loop.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"147 ","pages":"Article 104029"},"PeriodicalIF":1.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420947","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}

{"title":"High-pressure growth effect on the properties of high-Tc iron-based superconductors: A short review","authors":"Priya Singh,&nbsp;Manasa Manasa,&nbsp;Mohammad Azam,&nbsp;Shiv J. Singh","doi":"10.1016/j.cryogenics.2025.104028","DOIUrl":"10.1016/j.cryogenics.2025.104028","url":null,"abstract":"<div><div>The high-pressure growth technique is a vital approach that facilitates the stabilization of new phases and allows for meticulous control of structural parameters, which significantly impact electronic and magnetic properties. We present a short review of our ongoing investigations into various families of iron-based superconductors (IBS), employing the high-gas pressure and high-temperature synthesis (HP-HTS) method. This technique is capable of producing the gas pressures up to 1.8 GPa and a heating temperature of up to 1700 °C through a three-zone furnace within a cylindrical chamber. Different kinds of IBS samples are prepared using HP-HTS and characterized through various measurements to reach the final conclusions. The results demonstrate that the high-pressure growth technique significantly enhances the properties of IBS, including the transition temperature, critical current density, and pinning force. In addition, the quality of the samples and their density are improved through the intergrain connections. Furthermore, the comprehensive evaluations and investigations prove that a growth pressure of 0.5 GPa is sufficient for producing high-quality IBS bulks under the optimized synthesis conditions.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"147 ","pages":"Article 104028"},"PeriodicalIF":1.8,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143198157","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}

{"title":"Investigation of two-phase heat transfer coefficients of cryogenic nitrogen in 160-μm and 65-μm microchannels","authors":"Seungwhan Baek ,&nbsp;Ray Radebaugh ,&nbsp;Peter E Bradley","doi":"10.1016/j.cryogenics.2025.104026","DOIUrl":"10.1016/j.cryogenics.2025.104026","url":null,"abstract":"<div><div>In this study, the two-phase microheat transfer characteristics of cryogenic two-phase nitrogen were investigated. This basic information is required for the sequential design of mixed-refrigerant microcryocoolers. The effective heat exchanger must be designed with a hydraulic diameter (<em>D_h</em>) of less than 100 µm. The experimental setup was developed using microchannels with <em>D_h</em> values of 160 µm and 65 µm. The two-phase heat transfer coefficient was evaluated under different qualities (<em>x</em>), mass fluxes (<em>G</em> = 50–150 kg/m²s), and heat fluxes (<em>q’’=</em>5–15 kW/m²). The two-phase heat transfer coefficient values ranged from 5000 to 20000 W/m²K. The measured heat transfer coefficient values were compared with the predicted values from existing heat transfer correlations derived by Liu and Winterton. The mean percentage error (MPE) was as low as 25.6 %. Moreover, the correlation derived by Karayiannis and Mahmoud, which was derived for ambient-temperature applications, was found suitable for predicting previous cryogenic microchannel literature data (<em>D_h</em>: 300–10000 µm). When applying these findings to mixed refrigerants in microchannels, it is crucial to account for the reduced influence of mass flux on nucleate boiling and the dominance of thin-film evaporation under varying heat flux conditions in confined microscale geometries.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"147 ","pages":"Article 104026"},"PeriodicalIF":1.8,"publicationDate":"2025-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143198158","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}

{"title":"Study on the eddy current losses and thermal characteristic of a conduction-cooled HTS energy storage magnet","authors":"Yunshu Zhou ,&nbsp;Li Li ,&nbsp;Mingzhen Yang ,&nbsp;Yifeng Qiu ,&nbsp;Li Ren ,&nbsp;Ying Xu ,&nbsp;Jing Shi","doi":"10.1016/j.cryogenics.2025.104027","DOIUrl":"10.1016/j.cryogenics.2025.104027","url":null,"abstract":"<div><div>During the dynamic response of conduction-cooled high temperature superconductor (HTS) energy storage magnet, the AC loss of the magnet and the eddy current losses of the cold-conducting plates are generated. These two losses seriously threaten the thermal stability of the magnet, especially eddy current losses when the cold-conducting plates are not slit. Therefore, it is important to find a simple and effective way to model and reduce eddy current losses of cold-conducting plates for the sake of thermal stability. In this paper, both an effective 3D model to evaluate eddy current losses of cold-conducting plates and an efficient reduction scheme are proposed. The results prove that the eddy current loss of single cold-conducting plate is reduced by 99.9%, but the existence of longitudinal slit greatly affects its heat transfer efficiency. The epoxy impregnation method is further proposed to alleviate this influence availably, and the validity of homogenization method in the thermal analysis of magnets is verified.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"146 ","pages":"Article 104027"},"PeriodicalIF":1.8,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143159306","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}

{"title":"Nusselt number correction for stacked wire mesh considering finite heat capacity below 50 K","authors":"Zhengkun Li ,&nbsp;Xupeng Ding ,&nbsp;Yanyan Chen ,&nbsp;Xiaotao Wang ,&nbsp;Wei Dai","doi":"10.1016/j.cryogenics.2025.104025","DOIUrl":"10.1016/j.cryogenics.2025.104025","url":null,"abstract":"<div><div>In regenerative cooling systems, the heat transfer characteristics of regenerators employing stacked wire mesh are critically important. Numerous experimental and numerical investigations have been conducted to characterize the Nusselt number of regenerators, focusing on room temperature conditions where the solid heat capacity is sufficiently large compared to that of the gas . In this study, the #400 stainless steel mesh is simulated in three dimensions at pore scale to investigate the Nusselt number across various flow conditions, considering both unidirectional and oscillating flow. Under unidirectional flow, the heat transfer characteristics below 77 K are studied. Considering the influence of finite heat capacity of stainless steel, a modified Nusselt number formula applicable to the 50 K to 20 K range is generalized. Subsequently, the heat transfer characteristics under oscillating flow, including different frequencies and pressure ratios, are investigated. The results provide further evidence supporting the similarity of Nusselt numbers between oscillating and unidirectional flow. This study provides a deeper insight into the heat transfer characteristics of wire mesh regenerators at low temperatures. Meanwhile, the forementioned modified coefficient can be used for better regenerator simulations.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"146 ","pages":"Article 104025"},"PeriodicalIF":1.8,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143159305","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}

{"title":"Impact of fibre reinforcement on cryogenic performance of novel epoxy composites for cryogenic applications","authors":"A. Krzak ,&nbsp;A.J. Nowak ,&nbsp;J. Frolec ,&nbsp;T. Králík ,&nbsp;D. Boroński ,&nbsp;M. Kotyk","doi":"10.1016/j.cryogenics.2024.103995","DOIUrl":"10.1016/j.cryogenics.2024.103995","url":null,"abstract":"<div><div>Due to the dynamic development of technology and science, there is an increasing demand for materials combining high mechanical resistance to extreme temperature conditions and suitable thermal properties. Especially the knowledge of heat transfers by conduction and thermal radiation is crucial for the successful design of devices operating at cryogenic temperatures, such as Dewars, cryostats, or space probes. This study aimed to assess important thermal and mechanical properties at cryogenic temperatures for three composite materials made of identical epoxy resin reinforced by carbon, basalt or glass fibres. Apart from loading/unloading cyclic tensile tests conducted at room temperature and in cryogenic environments at 77 K, thermal conductivity and total hemispherical emissivity were obtained in wide temperature ranges from 5 K up to 300 K. The results highlighted the importance of the fibre material and have potential to help with optimal material selection. We found that the initial stiffness of the laminates increased at low temperatures, and the glass composite exhibited the best mechanical properties. On the other hand, the carbon composite showed the lowest but steeply increasing thermal conductivity with increasing temperature. This, together with the lowest emissivity, makes the carbon composite a more favourable option for the lowest temperatures.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"145 ","pages":"Article 103995"},"PeriodicalIF":1.8,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143143861","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}

{"title":"Effect of cryogenic treatment on the mechanical properties of 3D-printed polylactic acid part","authors":"Ayushi Gupta ,&nbsp;Narendra Kumar ,&nbsp;Anish Sachdeva ,&nbsp;Gourav Kumar Sharma ,&nbsp;Manas Kumar ,&nbsp;Ravi Verma","doi":"10.1016/j.cryogenics.2024.104000","DOIUrl":"10.1016/j.cryogenics.2024.104000","url":null,"abstract":"<div><div>The article investigates the effect of cryogenic treatment on the 3-D printed Polylactic Acid (PLA) specimen. It was found that exposure of PLA specimens to the cryogenic temperature (10 K) using a cryocooler led to a 35 % increase in tensile strength in 5 h, with most improvement occurring within the first hour. The cryogenic treatment enhanced the PLA specimen’s strength and ductility due to increased crystallinity and better molecular alignment. It is likely due to the interaction of the cooling medium (helium) used in the cryocooler with the PLA specimens. Towards this, EDS analysis is performed on cryo-treated PLA specimens. The EDS analysis reveals that nickel and iron compounds were detected on the surface of the cryogenic-treated PLA specimen. These findings highlight that cryogenic treatment significantly improves PLA specimen’s mechanical properties and tensile strength. However, challenges arise, including delamination-layer separation caused by internal stresses, and must be addressed. This work will be helpful for researchers working in polymer 3-D printing.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"145 ","pages":"Article 104000"},"PeriodicalIF":1.8,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145090","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}

{"title":"Modeling surface tension of ten binary cryogenic mixtures with a thermodynamic method and artificial neural network","authors":"Mariano Pierantozzi ,&nbsp;Zahra Rahmani ,&nbsp;Shahin Khosharay","doi":"10.1016/j.cryogenics.2024.103997","DOIUrl":"10.1016/j.cryogenics.2024.103997","url":null,"abstract":"<div><div>The phase equilibrium calculations between the liquid and surface phase are conducted to predict the surface tension and interfacial mole fractions of the components for ten binary cryogenic systems. This thermodynamic model is combined with the perturbed chain statistical association fluid theory equation of state to determine the fugacity coefficients and molar volumes of the components. Based on the application of molar or partial molar volumes, 4 different strategies are applied to the molar surface area of this model. The results of the thermodynamic model indicate that the first strategy has the best predictions for most cases. Then an artificial neural network has been applied to the surface tension of these ten mixtures. This model contains four input parameters and 9 neurons with a single layer. The overall good predictive capability of the artificial neural network model is proved with an R² of 0.999 and an AAD_γ% of 0.94 for the entire dataset.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"145 ","pages":"Article 103997"},"PeriodicalIF":1.8,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143143862","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}

{"title":"Analysis of the critical current and electromagnetic forces of HTS segments in multiple pairs of current leads used in the current lead box of a fusion reactor","authors":"Hu Cheng ,&nbsp;Yujun Dong ,&nbsp;Shuangsong Du ,&nbsp;Qingquan Zhang ,&nbsp;Qingxiang Ran ,&nbsp;Mohmmed Mun ELseed Hassaan ,&nbsp;Runze Li ,&nbsp;Chunlong Zou ,&nbsp;Kaizhong Ding","doi":"10.1016/j.cryogenics.2024.103984","DOIUrl":"10.1016/j.cryogenics.2024.103984","url":null,"abstract":"<div><div>The high-temperature superconducting current leads (HTS CLs) used in fusion reactors require multiple HTS CLs to be placed inside the current lead box (CLB) of specified dimensions. Each HTS CL not only carries a large current but also has very high safety requirements. This study, based on the first generation HTS tapes (Bi-2223/Ag-Au), analyzed the critical current distribution of a 60 kA HTS CL and evaluated optimal power supply configurations for eight HTS CLs within the CLB. It also determined the optimal distance of each lead from the center of the CLB. Through ANSYS APDL calculations, we first obtained the critical current distribution of each panel of a single CL. The analysis results indicated that the HTS segment has a current carrying capacity of 78 kA at 65 K. Secondly, the optimal power supply option adopted a positive–negative alternating approach. When the distance is 1200 mm, the total current carrying capacity of the eight CLs is 605 kA, with relatively minor differences among the minimum panels of each lead, and the electromagnetic forces for each current lead were all below 1000 N. In addition, the relationships of the critical currents, surface areas of the CLB and electromagnetic forces of eight CLs with distance were obtained. Based on the above analysis, the distance of each lead from the center of the CLB was determined to be at least 800 mm.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"145 ","pages":"Article 103984"},"PeriodicalIF":1.8,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143143863","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}

{"title":"Electro-magnetic-mechanical characteristics of 3D HTS INS and NI racetrack coils in complex physical fields","authors":"Wenhai Zhou ,&nbsp;Bingxu Su ,&nbsp;Rongli Jia ,&nbsp;Jiafeng Cao","doi":"10.1016/j.cryogenics.2024.104003","DOIUrl":"10.1016/j.cryogenics.2024.104003","url":null,"abstract":"<div><div>To investigate the impact of insulation structure on the electromagnetic and mechanical properties of high-temperature superconducting (HTS) coils, numerical simulations are employed. A comparative study is conducted on the electrical, magnetic, and force distribution characteristics of three-dimensional (3D) racetrack insulating (INS) HTS coils versus non-insulating (NI) HTS coils under identical operating conditions and dimensions. To balance computational complexity and time, a 3D racetrack-type homogenization equivalent model is developed. INS HTS coil has no inter-turn resistance so that the current dimension is reduced by one level. A homogeneous <strong>T-A</strong> formula is used to establish anisotropic equivalent model, which enables addressing the 3D computational challenges of high aspect ratio superconductors. NI HTS coil is solved by <strong>H</strong>-method due to the presence of radial resistance. In this pure FEM model, which is not coupled with the circuit model, the real geometry in arc segment of the NI HTS coil can be equated to a concentric circle structure by using the rotational anisotropic resistivity method. It can be achieved by setting the resistivity matrix <em>ρ_coil</em>. Meanwhile, to explore the weakening effect of the strain inside superconducting coil on superconducting performance under multi-physical fields, the application scope of the strain dependence formula of <em>I</em>_c under one-dimensional (1D) mechanical loading (Ekin’s power-law formula combined with Weibull distribution function) is extended from 1D loading to 3D complex stress state. And its accuracy is verified. Then the extended formula is applied to two 3D coils. The influence of mechanical loading on the critical performance of the coil under multi-physical field conditions is compared and investigated.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"145 ","pages":"Article 104003"},"PeriodicalIF":1.8,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145088","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}