Pub Date : 2024-10-16DOI: 10.1016/j.cryogenics.2024.103958
Tianbiao He , Min Zhou , Jinyang Han , Meng Qi , Ning Mao
Cryogenic CO2 separation from natural gas is a promising technology due to its environmental benefits and smaller spatial requirement. Nonetheless, the dynamics of CO2 desublimation and subsequent frost layer formation under cryogenic conditions for natural gas pre-treatment remain largely unexplored. Addressing this gap, this paper presents a novel numerical simulation approach by integrating desublimation phase change model and vapor-solid phase equilibrium model to investigate CO2 frost layer formation on the cold wall, revealing that both the cold wall temperature and the initial CO2 concentration significantly influence the thickness of the CO2 frost layer. Moreover, the study finds that the density of frost layer intensifies over time, with the highest density observed near the cold surface. Furthermore, increasing the cold wall temperature and the flow rate not only increases the average density of the CO2 frost layer but also affects the outlet CO2 concentration. To adhere to specific outlet CO2 concentration targets and desublimation duration, it is critical to adjust the cold wall temperature and the inlet flow velocity dynamically. Therefore, cryogenic CO2 removal methods, by reducing the spatial requirements of CO2 pre-treatment units, offer a practical and efficient solution for small-scale natural gas liquefaction plants. This approach not only facilitates operational efficiency but also contributes to the broader effort of mitigating greenhouse gas emissions, aligning with environmental sustainability objectives.
{"title":"A novel numerical simulation approach for cryogenic CO2 frosting in binary mixture gas by integrating desublimation and gas-solid phase equilibrium models","authors":"Tianbiao He , Min Zhou , Jinyang Han , Meng Qi , Ning Mao","doi":"10.1016/j.cryogenics.2024.103958","DOIUrl":"10.1016/j.cryogenics.2024.103958","url":null,"abstract":"<div><div>Cryogenic CO<sub>2</sub> separation from natural gas is a promising technology due to its environmental benefits and smaller spatial requirement. Nonetheless, the dynamics of CO<sub>2</sub> desublimation and subsequent frost layer formation under cryogenic conditions for natural gas pre-treatment remain largely unexplored. Addressing this gap, this paper presents a novel numerical simulation approach by integrating desublimation phase change model and vapor-solid phase equilibrium model to investigate CO<sub>2</sub> frost layer formation on the cold wall, revealing that both the cold wall temperature and the initial CO<sub>2</sub> concentration significantly influence the thickness of the CO<sub>2</sub> frost layer. Moreover, the study finds that the density of frost layer intensifies over time, with the highest density observed near the cold surface. Furthermore, increasing the cold wall temperature and the flow rate not only increases the average density of the CO<sub>2</sub> frost layer but also affects the outlet CO<sub>2</sub> concentration. To adhere to specific outlet CO<sub>2</sub> concentration targets and desublimation duration, it is critical to adjust the cold wall temperature and the inlet flow velocity dynamically. Therefore, cryogenic CO<sub>2</sub> removal methods, by reducing the spatial requirements of CO<sub>2</sub> pre-treatment units, offer a practical and efficient solution for small-scale natural gas liquefaction plants. This approach not only facilitates operational efficiency but also contributes to the broader effort of mitigating greenhouse gas emissions, aligning with environmental sustainability objectives.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"144 ","pages":"Article 103958"},"PeriodicalIF":1.8,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527983","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 : 2024-10-14DOI: 10.1016/j.cryogenics.2024.103962
Mansu Seo , Sejin Kwon
The need to densify oxidizers using cryogenic fluids is increasing to enhance the performance of launch vehicles. One of the most practical methods for oxidizer densification is heat exchange cooling between liquid oxygen and liquid nitrogen, typically using a tube bundle heat exchanger. Due to the multiple tubes in the bundle, a bundle effect arises, which enhances convective heat transfer by inducing liquid agitation from bubble generation and rising. This paper presents experimental results and prediction models that account for bubble behavior in a tube bundle. The experiment is conducted with saturated liquid nitrogen in a pool at atmospheric pressure and helical coil-type heat exchangers instead of a traditional tube bundle stack heat exchanger. Liquid oxygen densification is achieved by varying mass flow rates and inlet temperatures. Single-passage helical coils made of copper are used to minimize uncertainty from maldistribution flow and reduce thermal resistance compared to convective heat transfer coefficients in the inner and outer tubes. The coils, with an outer diameter of 12.7 mm, were tested in both vertical and horizontal directions and with various coil pitches. The bundle effect was clearly observed under helical coil conditions, and the experiment confirmed that the convective heat transfer coefficient increased with increasing heat flux and bubble generation rate. The prediction models considering bubble behavior—rising and generation rate—were validated by comparison with experimental results. The forced convective Nusselt number, experimentally measured to range from 23 to 361 through its correlation with the Boiling Reynolds number, closely followed the predicted correlation curve of the bubble generation model. It demonstrated a mean absolute error of 83.3, a standard deviation of 65.6, and an average relative error of 64.8 %. These values show improved accuracy compared to the relative errors of two predicted curves in the bubble rising model: 216 % for the single circular tube correlation and 381 % for tube bank correlations. This improvement suggests that the increased bubble generation rate with heat flux is better reflected for liquid oxygen densification with a helical coil submerged in large-scale static pool condition.
{"title":"Bundle effect on a helical coil in liquid nitrogen with pool boiling for liquid oxygen densification","authors":"Mansu Seo , Sejin Kwon","doi":"10.1016/j.cryogenics.2024.103962","DOIUrl":"10.1016/j.cryogenics.2024.103962","url":null,"abstract":"<div><div>The need to densify oxidizers using cryogenic fluids is increasing to enhance the performance of launch vehicles. One of the most practical methods for oxidizer densification is heat exchange cooling between liquid oxygen and liquid nitrogen, typically using a tube bundle heat exchanger. Due to the multiple tubes in the bundle, a bundle effect arises, which enhances convective heat transfer by inducing liquid agitation from bubble generation and rising. This paper presents experimental results and prediction models that account for bubble behavior in a tube bundle. The experiment is conducted with saturated liquid nitrogen in a pool at atmospheric pressure and helical coil-type heat exchangers instead of a traditional tube bundle stack heat exchanger. Liquid oxygen densification is achieved by varying mass flow rates and inlet temperatures. Single-passage helical coils made of copper are used to minimize uncertainty from maldistribution flow and reduce thermal resistance compared to convective heat transfer coefficients in the inner and outer tubes. The coils, with an outer diameter of 12.7 mm, were tested in both vertical and horizontal directions and with various coil pitches. The bundle effect was clearly observed under helical coil conditions, and the experiment confirmed that the convective heat transfer coefficient increased with increasing heat flux and bubble generation rate. The prediction models considering bubble behavior—rising and generation rate—were validated by comparison with experimental results. The forced convective Nusselt number, experimentally measured to range from 23 to 361 through its correlation with the Boiling Reynolds number, closely followed the predicted correlation curve of the bubble generation model. It demonstrated a mean absolute error of 83.3, a standard deviation of 65.6, and an average relative error of 64.8 %. These values show improved accuracy compared to the relative errors of two predicted curves in the bubble rising model: 216 % for the single circular tube correlation and 381 % for tube bank correlations. This improvement suggests that the increased bubble generation rate with heat flux is better reflected for liquid oxygen densification with a helical coil submerged in large-scale static pool condition.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"144 ","pages":"Article 103962"},"PeriodicalIF":1.8,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527979","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 : 2024-10-09DOI: 10.1016/j.cryogenics.2024.103956
N. Sala , A. Bersani , M. Bracco , B. Caiffi , S. Farinon , A. Gagno , F. Levi , D. Novelli , R. Musenich , A. Pampaloni , M. Sorbi , R.U. Valente
When approaching the mechanical design of a superconducting magnet, whenever possible the starting model is a 2D approximation. If rotational symmetry (solenoid-like winding) is present, the 2D representation is unique and contains no approximations. If, on the other hand, a non-axisymmetric system is opted for, the 2D representation is not unique and there are main options available, as plane stress, plane stress with thickness, plane strain and generalized plane strain. Considering z as the direction normal to the 2D plane, the plane stress option defines a stress state in which no normal or shear stresses perpendicular to the xy plane can occur (). In this option, deformation can occur in the thickness direction of the element, which will become thinner when stretched and thicker when compressed; it is generally used for objects with limited depth (thin objects).
In contrast, plane strain refers to the fact that deformation can only occur in plane, which means that no out-of-plane deformation will occur (). The plane strain option is generally appropriate for structures of nearly infinite length, relative to their cross section, that exhibit negligible length changes under load. The “generalized plane strain” option imposes the axial strain equal to a constant value; this condition does not reproduce the real operating condition of the magnet and is therefore excluded. The “plane stress with thickness” uses the same equations as the plane stress option but, output quantities are given per unit length defined with thickness; therefore, it is again excluded from the comparison. Superconducting magnets, such as dipoles, do not fit neatly into any of the above options: they are far from thin but deform longitudinally under load. This work reports a comparative study of plane stress and plane strain in the specific case study of a dipole magnet.
在进行超导磁体的机械设计时，只要有可能，起始模型就是二维近似模型。如果存在旋转对称（类似螺线管的绕组），二维表示法是唯一的，不包含近似值。另一方面，如果选择非轴对称系统，则二维表示法并非唯一，主要有平面应力、带厚度的平面应力、平面应变和广义平面应变等选项。考虑到 z 是二维平面的法线方向，平面应力选项定义了一种应力状态，在这种状态下不会产生垂直于 xy 平面的法向应力或剪应力（σz=σxz=σyz=0）。相比之下，平面应变指的是变形只能在平面内发生，即不会发生平面外变形（ϵz=ϵxz=ϵyz=0）。平面应变选项通常适用于相对于横截面几乎无限长的结构，这些结构在载荷作用下的长度变化可以忽略不计。广义平面应变 "选项施加的轴向应变等于一个恒定值；这种情况无法再现磁体的实际运行状况，因此不在计算之列。有厚度的平面应力 "使用与平面应力选项相同的方程，但输出量是以厚度定义的单位长度给出的；因此，它再次被排除在比较之外。超导磁体（如偶极子）并不完全符合上述任何一种方案：它们远非很薄，但在载荷作用下会发生纵向变形。本研究报告以偶极子磁体为具体案例，对平面应力和平面应变进行了比较研究。
{"title":"2D mechanical representation of superconducting magnets: A comparative study of plane stress and plane strain","authors":"N. Sala , A. Bersani , M. Bracco , B. Caiffi , S. Farinon , A. Gagno , F. Levi , D. Novelli , R. Musenich , A. Pampaloni , M. Sorbi , R.U. Valente","doi":"10.1016/j.cryogenics.2024.103956","DOIUrl":"10.1016/j.cryogenics.2024.103956","url":null,"abstract":"<div><div>When approaching the mechanical design of a superconducting magnet, whenever possible the starting model is a 2D approximation. If rotational symmetry (solenoid-like winding) is present, the 2D representation is unique and contains no approximations. If, on the other hand, a non-axisymmetric system is opted for, the 2D representation is not unique and there are main options available, as plane stress, plane stress with thickness, plane strain and generalized plane strain. Considering z as the direction normal to the 2D plane, the plane stress option defines a stress state in which no normal or shear stresses perpendicular to the xy plane can occur (<span><math><msub><mrow><mi>σ</mi></mrow><mrow><mi>z</mi></mrow></msub><mo>=</mo><msub><mrow><mi>σ</mi></mrow><mrow><mi>x</mi><mi>z</mi></mrow></msub><mo>=</mo><msub><mrow><mi>σ</mi></mrow><mrow><mi>y</mi><mi>z</mi></mrow></msub><mo>=</mo><mn>0</mn></math></span>). In this option, deformation can occur in the thickness direction of the element, which will become thinner when stretched and thicker when compressed; it is generally used for objects with limited depth (thin objects).</div><div>In contrast, plane strain refers to the fact that deformation can only occur in plane, which means that no out-of-plane deformation will occur (<span><math><msub><mrow><mi>ϵ</mi></mrow><mrow><mi>z</mi></mrow></msub><mo>=</mo><msub><mrow><mi>ϵ</mi></mrow><mrow><mi>x</mi><mi>z</mi></mrow></msub><mo>=</mo><msub><mrow><mi>ϵ</mi></mrow><mrow><mi>y</mi><mi>z</mi></mrow></msub><mo>=</mo><mn>0</mn></math></span>). The plane strain option is generally appropriate for structures of nearly infinite length, relative to their cross section, that exhibit negligible length changes under load. The “generalized plane strain” option imposes the axial strain equal to a constant value; this condition does not reproduce the real operating condition of the magnet and is therefore excluded. The “plane stress with thickness” uses the same equations as the plane stress option but, output quantities are given per unit length defined with thickness; therefore, it is again excluded from the comparison. Superconducting magnets, such as dipoles, do not fit neatly into any of the above options: they are far from thin but deform longitudinally under load. This work reports a comparative study of plane stress and plane strain in the specific case study of a dipole magnet.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"144 ","pages":"Article 103956"},"PeriodicalIF":1.8,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527982","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 : 2024-10-01DOI: 10.1016/j.cryogenics.2024.103955
Zuhua Chen , Shilin Yu , Guochun Zhang , Changkun Wang , Jiahao Gao , Yicai Zhang , Yanan Zhao , Zhenxing Li , Jun Shen , Heng Tu
The adiabatic demagnetization refrigeration based on the magnetocaloric effect of magnetic materials has been regarded as an effective technology to attain sub-Kelvin temperature. In this article, the magnetic properties and MCE of Na5Gd4F(SiO4)4 compound are investigated. Due to the high Gd3+ ion/anion ligand ratio and weak magnetic interaction, Na5Gd4F(SiO4)4 exhibits a large magnetic entropy change of 49.6 J·kg−1·K−1 under magnetic field change of 0–7 T at 2.6 K, which surpasses the commercial magnetic refrigerant Gd3Ga5O12 under the same conditions. Besides, its refrigeration capacity and the relative cooling power under magnetic field change of 0–7 T reaches up to 308.9 J·kg−1 and 406.7 J·kg−1, respectively. These properties indicate that Na5Gd4F(SiO4)4 compound is a promising magnetic refrigeration material.
基于磁性材料磁致效应的绝热退磁制冷一直被认为是达到亚开尔文温度的有效技术。本文研究了 Na5Gd4F(SiO4)4 化合物的磁性能和 MCE。由于 Na5Gd4F(SiO4)4 具有较高的 Gd3+ 离子/阴离子配位比和弱磁相互作用，因此在 2.6 K 条件下，当磁场变化为 0-7 T 时，Na5Gd4F(SiO4)4 的磁熵变化高达 49.6 J-kg-1-K-1，超过了相同条件下的商用磁性制冷剂 Gd3Ga5O12。此外，在 0-7 T 的磁场变化下，其制冷量和相对制冷功率分别达到 308.9 J-kg-1 和 406.7 J-kg-1。这些特性表明，Na5Gd4F(SiO4)4 化合物是一种很有前途的磁性制冷材料。
{"title":"Large cryogenic magnetocaloric effect in Na5Gd4F(SiO4)4","authors":"Zuhua Chen , Shilin Yu , Guochun Zhang , Changkun Wang , Jiahao Gao , Yicai Zhang , Yanan Zhao , Zhenxing Li , Jun Shen , Heng Tu","doi":"10.1016/j.cryogenics.2024.103955","DOIUrl":"10.1016/j.cryogenics.2024.103955","url":null,"abstract":"<div><div>The adiabatic demagnetization refrigeration based on the magnetocaloric effect of magnetic materials has been regarded as an effective technology to attain sub-Kelvin temperature. In this article, the magnetic properties and MCE of Na<sub>5</sub>Gd<sub>4</sub>F(SiO<sub>4</sub>)<sub>4</sub> compound are investigated. Due to the high Gd<sup>3+</sup> ion/anion ligand ratio and weak magnetic interaction, Na<sub>5</sub>Gd<sub>4</sub>F(SiO<sub>4</sub>)<sub>4</sub> exhibits a large magnetic entropy change of 49.6 J·kg<sup>−1</sup>·K<sup>−1</sup> under magnetic field change of 0–7 T at 2.6 K, which surpasses the commercial magnetic refrigerant Gd<sub>3</sub>Ga<sub>5</sub>O<sub>12</sub> under the same conditions. Besides, its refrigeration capacity and the relative cooling power under magnetic field change of 0–7 T reaches up to 308.9 J·kg<sup>−1</sup> and 406.7 J·kg<sup>−1</sup>, respectively. These properties indicate that Na<sub>5</sub>Gd<sub>4</sub>F(SiO<sub>4</sub>)<sub>4</sub> compound is a promising magnetic refrigeration material.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"143 ","pages":"Article 103955"},"PeriodicalIF":1.8,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142426220","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}
Cryogenic distillation is the primary method for air separation, with corrugated plate packing as the main packing for heat and mass transfer between nitrogen and oxygen. The perforated structure on the corrugated plate packing can directly change the liquid distribution characteristics, thereby affecting the packing’s flow and mass transfer performance. Currently, the effect of perforated structure is mainly revealed by room temperature fluids such as water and air, while on the practical cryogenic fluids such as liquid nitrogen, it is seldom studied. In this study, the effects of perforation size ranging from 2 to 8 mm on the flow of water and liquid nitrogen on the perforated plates were investigated and compared by a high-speed camera. It was observed that water could hardly flow through the perforations, it completely covers the perforations, forming a continuous liquid film on the surface of the perforations. The expected role of perforations in redistributing water on the back side of the corrugated plate is relatively minor. While for liquid nitrogen, the presence of the perforated structure helps fluid redistribution on the back side of the plate, as it can easily flow through the perforations with diameters between 2 mm and 8 mm. It is found that when the perforation diameter exceeds 6 mm, liquid nitrogen will form suspended liquid droplets within the holes, which could be a risk of premature flooding. Under similar conditions, the wetting rate of liquid nitrogen reaches 86.90 % −99.48 %, higher than that of water which is about 10.26 % −78.82 %. The results show that perforations have quite different effects on the flow characters of water and liquid nitrogen due to their disparate physic properties.
{"title":"Comparative experiments on the flow morphology of liquid nitrogen and water in perforated structured packing","authors":"Xiaoqin Zhi, Yixuan Teng, Gaoming Zhan, Huabin Zhou, Shaolong Zhu, Limin Qiu","doi":"10.1016/j.cryogenics.2024.103948","DOIUrl":"10.1016/j.cryogenics.2024.103948","url":null,"abstract":"<div><div>Cryogenic distillation is the primary method for air separation, with corrugated plate packing as the main packing for heat and mass transfer between nitrogen and oxygen. The perforated structure on the corrugated plate packing can directly change the liquid distribution characteristics, thereby affecting the packing’s flow and mass transfer performance. Currently, the effect of perforated structure is mainly revealed by room temperature fluids such as water and air, while on the practical cryogenic fluids such as liquid nitrogen, it is seldom studied. In this study, the effects of perforation size ranging from 2 to 8 mm on the flow of water and liquid nitrogen on the perforated plates were investigated and compared by a high-speed camera. It was observed that water could hardly flow through the perforations, it completely covers the perforations, forming a continuous liquid film on the surface of the perforations. The expected role of perforations in redistributing water on the back side of the corrugated plate is relatively minor. While for liquid nitrogen, the presence of the perforated structure helps fluid redistribution on the back side of the plate, as it can easily flow through the perforations with diameters between 2 mm and 8 mm. It is found that when the perforation diameter exceeds 6 mm, liquid nitrogen will form suspended liquid droplets within the holes, which could be a risk of premature flooding. Under similar conditions, the wetting rate of liquid nitrogen reaches 86.90 % −99.48 %, higher than that of water which is about 10.26 % −78.82 %. The results show that perforations have quite different effects on the flow characters of water and liquid nitrogen due to their disparate physic properties.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"143 ","pages":"Article 103948"},"PeriodicalIF":1.8,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142426218","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 : 2024-10-01DOI: 10.1016/j.cryogenics.2024.103954
Changjun Li , Caigong Zhang , Jing Xu , Yang Chen , Chao Chen , Ziyuan Li , Zhuang Guo
Accurate and efficient prediction of the properties of helium-4 (He-4) via an equation of state (EOS) is a prerequisite for evaluating liquid helium-4 (LHe-4) storage technology. However, the performance of the Peng–Robinson (PR) EOS in predicting the density of LHe-4 and vapour helium-4 (VHe-4) deteriorates within the thermodynamic ranges of the LHe-4 tank: 3–50 K and 60–600 kPa. To modify the PR EOS, we establish first-order and second-order Feynman–Hibbs (FH)-corrected EXP-6 potentials and propose a reduced effective particle diameter (REPD) correlation with four parameters to consider the quantum swelling effects of LHe-4. On the basis of the rational function form of the REPD correlation, we introduce a quantum-corrected covolume term to develop a regression model for the FH-corrected Peng–Robinson (FH-PR) EOS. Moreover, to improve the effectiveness of regression near the saturation curve, we propose a hypothetical boundary consisting of the saturation curve from 3 K to the critical temperature and a virtual saturation curve from the critical pressure to 600 kPa. The results indicate that the FH − PR EOS shows satisfactory engineering application performance in predicting the density of He-4 within the studied range. Under verification conditions, the average absolute relative deviation (AARD) of the density determined via the FH − PR EOS ranges from 0.72 % to 1.77 %, and the maximum relative deviation (MRD) ranges from 2.17 % to 5.62 %. Under test conditions, the AARD of the density ranged from 1.06 % to 1.71 %, and the MRD ranged from 3.77 % to 7.38 %.
{"title":"A quantum-corrected Peng‒Robinson equation of state for helium-4 from 3 K to 50 K considering quantum swelling effects through the Feynman‒Hibbs correction of the EXP-6 potential","authors":"Changjun Li , Caigong Zhang , Jing Xu , Yang Chen , Chao Chen , Ziyuan Li , Zhuang Guo","doi":"10.1016/j.cryogenics.2024.103954","DOIUrl":"10.1016/j.cryogenics.2024.103954","url":null,"abstract":"<div><div>Accurate and efficient prediction of the properties of helium-4 (He-4) via an equation of state (EOS) is a prerequisite for evaluating liquid helium-4 (LHe-4) storage technology. However, the performance of the Peng–Robinson (PR) EOS in predicting the density of LHe-4 and vapour helium-4 (VHe-4) deteriorates within the thermodynamic ranges of the LHe-4 tank: 3–50 K and 60–600 kPa. To modify the PR EOS, we establish first-order and second-order Feynman–Hibbs (FH)-corrected EXP-6 potentials and propose a reduced effective particle diameter (REPD) correlation with four parameters to consider the quantum swelling effects of LHe-4. On the basis of the rational function form of the REPD correlation, we introduce a quantum-corrected covolume term to develop a regression model for the FH-corrected Peng–Robinson (FH-PR) EOS. Moreover, to improve the effectiveness of regression near the saturation curve, we propose a hypothetical boundary consisting of the saturation curve from 3 K to the critical temperature and a virtual saturation curve from the critical pressure to 600 kPa. The results indicate that the FH − PR EOS shows satisfactory engineering application performance in predicting the density of He-4 within the studied range. Under verification conditions, the average absolute relative deviation (AARD) of the density determined via the FH − PR EOS ranges from 0.72 % to 1.77 %, and the maximum relative deviation (MRD) ranges from 2.17 % to 5.62 %. Under test conditions, the AARD of the density ranged from 1.06 % to 1.71 %, and the MRD ranged from 3.77 % to 7.38 %.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"143 ","pages":"Article 103954"},"PeriodicalIF":1.8,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142426917","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 : 2024-10-01DOI: 10.1016/j.cryogenics.2024.103949
M. Búran, P. Kováč
This work presents a comprehensive 3D numerical model of MgB2 multi-filamentary superconducting wires using the Finite Element Method (FEM) software, COMSOL Multiphysics® 6.0. The study aims to investigate the electro-thermal behavior of MgB2 composite wires during standard transport measurements at various initial temperatures under subcooled water ice conditions. By solving a series of partial differential equations governing heat transfer and dynamic current transport, the model provides detailed insights into the wire’s performance. The simulation results are rigorously compared with experimental E-I characteristics measured for 6-filament MgB2 wires with internal copper stabilization. This comparison validates the model and highlights its capability to predict the behavior of superconducting wires under cryogenic conditions. The findings offer valuable data on the current distribution, ohmic losses, and overall thermal stability of the composite wires, contributing to the advancement of cryogen-free superconducting technologies. This study bridges the gap in the literature regarding the electrothermal dynamics of MgB2 wires cooled by subcooled water ice, providing a foundation for further research and practical applications in high-field generation devices.
{"title":"Numerical modelling and measurement of the E-I characteristics of MgB2 wire in sub-cooled water ice","authors":"M. Búran, P. Kováč","doi":"10.1016/j.cryogenics.2024.103949","DOIUrl":"10.1016/j.cryogenics.2024.103949","url":null,"abstract":"<div><div>This work presents a comprehensive 3D numerical model of MgB<sub>2</sub> multi-filamentary superconducting wires using the Finite Element Method (FEM) software, COMSOL Multiphysics® 6.0. The study aims to investigate the electro-thermal behavior of MgB<sub>2</sub> composite wires during standard transport measurements at various initial temperatures under subcooled water ice conditions. By solving a series of partial differential equations governing heat transfer and dynamic current transport, the model provides detailed insights into the wire’s performance. The simulation results are rigorously compared with experimental E-I characteristics measured for 6-filament MgB<sub>2</sub> wires with internal copper stabilization. This comparison validates the model and highlights its capability to predict the behavior of superconducting wires under cryogenic conditions. The findings offer valuable data on the current distribution, ohmic losses, and overall thermal stability of the composite wires, contributing to the advancement of cryogen-free superconducting technologies. This study bridges the gap in the literature regarding the electrothermal dynamics of MgB<sub>2</sub> wires cooled by subcooled water ice, providing a foundation for further research and practical applications in high-field generation devices.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"143 ","pages":"Article 103949"},"PeriodicalIF":1.8,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142426219","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 : 2024-10-01DOI: 10.1016/j.cryogenics.2024.103953
Rong Bao , Wentao Sun , Zhixiong Wu , Chuanjun Huang , Laifeng Li , Yuan Zhou
Glass fiber-reinforced polymer (GFRP) composites, with epoxy resin or a blend of cyanate and epoxy resins as the matrix, have been used as insulating materials of high-field, large-scale superconducting magnets for accelerators and magnetic confinement fusion. However, the GFRP does not fully meet the requirements for the next generation of magnetic confinement fusion with respect to the mechanical and thermal performance at cryogenic temperature and huge electromagnetic stress. This paper introduces a method for enhancing both the mechanical and thermal properties of the GFRP composites using aluminum nitride (AlN) nanoparticles. The fabrication of the AlN-GFRP composite involved a method that combines “dip absorption” with vacuum-assisted resin transfer molding (VARTM). The dip absorption method was utilized to deposit AlN nanopowders onto glass fibers, resulting in the preparation of AlN-glass fiber layers. Subsequently, the AlN-woven glass fibers were incorporated to reinforce the cyanate ester/epoxy based composites using the VARTM technology. The mechanical and thermal properties of the AlN-GFRP composites were assessed across varying temperatures. The results indicate that the short-beam shear strength (SBS strength) of the AlN-GFRP composites improves at cryogenic temperatures compared to that of the GFRP composites without AlN. Additionally, enhanced thermal conductivities are observed across different temperature ranges for the AlN-GFRP composites. The coefficient of thermal expansion between 77 K and 300 K of the composites significantly decreases with the addition of the AlN nanopowders.
{"title":"Nano aluminum nitride fillers for enhanced mechanical and thermal properties of GFRP in cryogenic temperature settings","authors":"Rong Bao , Wentao Sun , Zhixiong Wu , Chuanjun Huang , Laifeng Li , Yuan Zhou","doi":"10.1016/j.cryogenics.2024.103953","DOIUrl":"10.1016/j.cryogenics.2024.103953","url":null,"abstract":"<div><div>Glass fiber-reinforced polymer (GFRP) composites, with epoxy resin or a blend of cyanate and epoxy resins as the matrix, have been used as insulating materials of high-field, large-scale superconducting magnets for accelerators and magnetic confinement fusion. However, the GFRP does not fully meet the requirements for the next generation of magnetic confinement fusion with respect to the mechanical and thermal performance at cryogenic temperature and huge electromagnetic stress. This paper introduces a method for enhancing both the mechanical and thermal properties of the GFRP composites using aluminum nitride (AlN) nanoparticles. The fabrication of the AlN-GFRP composite involved a method that combines “dip absorption” with vacuum-assisted resin transfer molding (VARTM). The dip absorption method was utilized to deposit AlN nanopowders onto glass fibers, resulting in the preparation of AlN-glass fiber layers. Subsequently, the AlN-woven glass fibers were incorporated to reinforce the cyanate ester/epoxy based composites using the VARTM technology. The mechanical and thermal properties of the AlN-GFRP composites were assessed across varying temperatures. The results indicate that the short-beam shear strength (SBS strength) of the AlN-GFRP composites improves at cryogenic temperatures compared to that of the GFRP composites without AlN. Additionally, enhanced thermal conductivities are observed across different temperature ranges for the AlN-GFRP composites. The coefficient of thermal expansion between 77 K and 300 K of the composites significantly decreases with the addition of the AlN nanopowders.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"143 ","pages":"Article 103953"},"PeriodicalIF":1.8,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142356928","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 : 2024-10-01DOI: 10.1016/j.cryogenics.2024.103957
Katsuyoshi Fukiba, Kohei Suda, Ibuki Hori
This study proposes a method to accelerate the chilldown process in pipes using liquid nitrogen flow. Axial grooves were machined along the inner surface of the pipe and then filled with silicone sealant. This approach achieves a shorter chilldown time compared to previously proposed methods. Initial experiments involving pool boiling in liquid nitrogen were conducted to determine the optimal groove width and the ratio of groove-to-sealant area. The shortest chilldown time in pool boiling was achieved when the groove pitch was close to the capillary length. The effect of the copper-to-silicone sealant area ratio on the chilldown process was minimal. The shortest chilldown time was achieved with a surface that had a 2 mm pitch and a copper-to-silicone sealant area ratio of 0.25. The chilldown time was 1/4.4 of that of the bare surface. Pipes with different pitch and groove widths were tested in a flow chilldown experiment. Using the surface texture, the chilldown time of a stainless-steel pipe with an outer diameter of 1/2″ and a length of 120 mm from room temperature to the saturation temperature was reduced to a maximum of 1/3.6. The shortest cooling time is obtained at a groove pitch of 2 mm. In addition to the shorter cooling time, the amount of liquid nitrogen required for chilldown was also reduced.
{"title":"Enhancing pipe chilldown with axial grooves filled with silicone sealant","authors":"Katsuyoshi Fukiba, Kohei Suda, Ibuki Hori","doi":"10.1016/j.cryogenics.2024.103957","DOIUrl":"10.1016/j.cryogenics.2024.103957","url":null,"abstract":"<div><div>This study proposes a method to accelerate the chilldown process in pipes using liquid nitrogen flow. Axial grooves were machined along the inner surface of the pipe and then filled with silicone sealant. This approach achieves a shorter chilldown time compared to previously proposed methods. Initial experiments involving pool boiling in liquid nitrogen were conducted to determine the optimal groove width and the ratio of groove-to-sealant area. The shortest chilldown time in pool boiling was achieved when the groove pitch was close to the capillary length. The effect of the copper-to-silicone sealant area ratio on the chilldown process was minimal. The shortest chilldown time was achieved with a surface that had a 2 mm pitch and a copper-to-silicone sealant area ratio of 0.25. The chilldown time was 1/4.4 of that of the bare surface. Pipes with different pitch and groove widths were tested in a flow chilldown experiment. Using the surface texture, the chilldown time of a stainless-steel pipe with an outer diameter of 1/2″ and a length of 120 mm from room temperature to the saturation temperature was reduced to a maximum of 1/3.6. The shortest cooling time is obtained at a groove pitch of 2 mm. In addition to the shorter cooling time, the amount of liquid nitrogen required for chilldown was also reduced.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"143 ","pages":"Article 103957"},"PeriodicalIF":1.8,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432608","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 : 2024-10-01DOI: 10.1016/j.cryogenics.2024.103961
Myeong-rok Ryu , Sungho Yun , Bo-kyong Kim , Daehoon Kang , Gildong Kim , Hyunbae Lee
This study examines the effects of hydrogen sloshing on internal pressure, temperature, and fluid behavior liquefied-hydrogen storage tanks designed for train usage by applying the natural frequency and frequency conditions from train vibration test standards. Notably, it investigates the impact on BOG generation using a transient volume-of-fluid phase change model. Here, simulations were conducted at vibrations of 0, 0.53, 1.53, and 3 Hz, which were established using sine wave acceleration. The results demonstrated that sloshing increased with higher frequencies, thereby resulting in a more intense heat transfer between the wall of the tanks and free surface of hydrogen and an increase in the BOG generation. Compared to the 0 Hz baseline, BOG generation increased by 13, 44, and 66 % at 0.53, 1.53, and 3 Hz, respectively.
{"title":"Numerical analysis of sloshing effects in cryogenic liquefied-hydrogen storage tanks for trains under various vibration conditions","authors":"Myeong-rok Ryu , Sungho Yun , Bo-kyong Kim , Daehoon Kang , Gildong Kim , Hyunbae Lee","doi":"10.1016/j.cryogenics.2024.103961","DOIUrl":"10.1016/j.cryogenics.2024.103961","url":null,"abstract":"<div><div>This study examines the effects of hydrogen sloshing on internal pressure, temperature, and fluid behavior liquefied-hydrogen storage tanks designed for train usage by applying the natural frequency and frequency conditions from train vibration test standards. Notably, it investigates the impact on BOG generation using a transient volume-of-fluid phase change model. Here, simulations were conducted at vibrations of 0, 0.53, 1.53, and 3 Hz, which were established using sine wave acceleration. The results demonstrated that sloshing increased with higher frequencies, thereby resulting in a more intense heat transfer between the wall of the tanks and free surface of hydrogen and an increase in the BOG generation. Compared to the 0 Hz baseline, BOG generation increased by 13, 44, and 66 % at 0.53, 1.53, and 3 Hz, respectively.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"143 ","pages":"Article 103961"},"PeriodicalIF":1.8,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142445053","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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