Cryogenics最新文献

{"title":"Optimization and analysis of a new liquefied natural gas and nitrogen cascade pre-cooling hydrogen liquefaction process","authors":"Shanshan Sun ,&nbsp;Wenquan Jiang ,&nbsp;Fan Yang ,&nbsp;Changshun Wang ,&nbsp;Junjie Liu ,&nbsp;Meng Yang","doi":"10.1016/j.cryogenics.2025.104253","DOIUrl":"10.1016/j.cryogenics.2025.104253","url":null,"abstract":"<div><div>Liquid hydrogen storage currently represents the most prominent method among hydrogen storage technologies. To minimize the energy demand of the hydrogen liquefaction system, a hydrogen liquefaction system which utilizes liquefied natural gas (LNG) and a nitrogen (N₂) reverse Brayton cycle for cascade pre-cooling of hydrogen is designed. The comparative analysis of the proposed hydrogen liquefaction improvement system with other systems shows that the proposed system has great advantages. Through systematic optimization, the system achieves a specific energy consumption (SEC) of 5.24 kWh/kg_LH2, a coefficient of performance (COP) of 0.254, and an exergy efficiency (<em>η</em>_ex) of 58.88%. Furthermore, by leveraging the surplus cold energy from LNG for pre-cooling the cryogenic refrigerant prior to inter-stage compression in the cryogenic cooling process, the SEC decreases by 8.87% and <em>η</em>_ex increases by 8.83% compared to conventional ambient temperature pre-cooling methods.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"153 ","pages":"Article 104253"},"PeriodicalIF":2.1,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682050","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":"AC loss analysis of magnetic gear system with superconducting component","authors":"Emre Akyerden,&nbsp;Ahmet Cansız","doi":"10.1016/j.cryogenics.2025.104255","DOIUrl":"10.1016/j.cryogenics.2025.104255","url":null,"abstract":"<div><div>Magnetic gears, which utilize specially arranged permanent magnets in rotating mechanisms, offer significant advantages over conventional mechanical gears. Despite their capability for high torque transmission, their industrial adoption remains limited due to torque density and loss constraints. To address this issue, recent studies have focused on improving flux modulation between the rotors through innovative magnetic and material configurations. Superconductors, with their unique electromagnetic properties, introduce new possibilities for enhancing magnetic gear performance. In this study, a superconducting magnetic gear system was analyzed using finite element simulations in COMSOL Multiphysics. A cylindrical coaxial magnetic gear with a 20/6 pole configuration was evaluated under three stator (pole piece) material arrangements: Steel &amp; Air, Steel &amp; Superconductor (SC), and Superconductor &amp; Air. Torque optimization was performed using the derivative-free BOBYQA algorithm, and AC (iron) losses were assessed based on the Bertotti loss model. The results demonstrate that optimization enhances torque transmission by factors of 3.5–5.1, while losses increase only 2.6–2.7 times. Across all configurations, the torque growth consistently outpaces the rise in losses, confirming an overall improvement in energy efficiency and torque density. Among the examined configurations, the Steel &amp; SC combination yielded the highest absolute torque, whereas the SC &amp; Air configuration exhibited the greatest relative improvement due to the absence of iron losses. These outcomes indicate that superconductors can substantially improve torque performance while maintaining manageable loss levels, effectively balancing the torque–loss trade-off. The study also reveals that optimization alters the effective gear ratio by modifying material volume distributions, underscoring a critical design consideration for superconducting magnetic gears. Overall, the findings provide valuable insights for multi-objective optimization strategies and offer a solid foundation for future experimental implementations.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"153 ","pages":"Article 104255"},"PeriodicalIF":2.1,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145732958","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":"Thermodynamic analysis of thermally-driven dilution refrigerator in a confined cell","authors":"Zhiheng Li ,&nbsp;Weijun Cheng ,&nbsp;Yanan Wang ,&nbsp;Wei Dai","doi":"10.1016/j.cryogenics.2025.104252","DOIUrl":"10.1016/j.cryogenics.2025.104252","url":null,"abstract":"<div><div>Thermally-driven dilution refrigerator (TDR) in a confined cell uses a superleak to inject or extract superfluid ⁴He into or out of a chamber containing ³He, thereby achieving the expansion or compression of ³He, and the expansion of ³He produces cooling. Its typical structure can be regarded as a refrigerator (³He expansion cell) driven by a thermal compressor (⁴He reservoir). The ³He expansion cell are equipped with an external cooler (EC₁) to dissipate compression heat, and the ⁴He reservoir has a heater and external cooler (EC₂) to drive the superfluid ⁴He. In this paper, we use equations of the energy conservation and the ³He-⁴He dilution process, and the chemical potential conservation of ⁴He to establish two physical models for the entire system. Based on these models, the cooling performance of the system is predicted, and the coefficient of performance (<em>COP</em>) and the thermodynamic second law efficiency of the system are analyzed. Firstly, the cooling power of EC₂ determines the flow rate of superfluid ⁴He into the ³He expansion cell and the cooling power of TDR during the isothermal expansion processes. If the cooling power of EC₂ is fixed during isothermal expansion process, the cooling power of TDR shows a trend of gradual increase over time. Secondly, the thermodynamic second law efficiency of the system is less than 3 % with a typical cooling temperature of EC₁ and EC₂ are 0.3 K and 0.9 K, respectively. Both incomplete compression and expansion of ³He have an impact on the efficiency of the system. Finally, increasing the temperature of EC₁ will significantly reduce <em>COP</em> and thermodynamic second law efficiency and increase the amount of ³He and ⁴He required.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"153 ","pages":"Article 104252"},"PeriodicalIF":2.1,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682049","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":"The offset and the performance of a valved linear compressor with anti-offset piston","authors":"Lei Ding ,&nbsp;Xinquan Sha ,&nbsp;Ran Hu ,&nbsp;Qi Huang ,&nbsp;Shaoshuai Liu ,&nbsp;Zhenhua Jiang ,&nbsp;Zhaohua Li ,&nbsp;Hua Zhang ,&nbsp;Yinong Wu","doi":"10.1016/j.cryogenics.2025.104251","DOIUrl":"10.1016/j.cryogenics.2025.104251","url":null,"abstract":"<div><div>As a critical driving component of the Joule-Thomson (JT) throttling cryocooler for space applications, the output characteristics of the valved linear compressor (VLC) determine the overall efficiency of the cryocooler. Piston offset is an inherent characteristic of the VLCs. To improve the output capacity and efficiency of VLCs, valved linear compressor integrated with an anti-offset piston was developed in this study. The anti-offset piston can effectively suppress the piston offset, enhance VLC performance, and ensure the stable and efficient operation of the throttling cryocooler. Experimental verification was conducted to measure piston offset and the output characteristics of the VLC with anti-offset piston under various operating parameters. The results indicate that with the increase of the piston stroke, the offset establishment time is prolonged, the offset suppression effect is more obvious, and the effective stroke of the compressor is increased by nearly 40 %. Meanwhile, the suction pressure decreases, the discharge pressure increases, and the maximum pressure ratio is enhanced by 54.2 %. Under the same operating parameters, compared with the compressor without offset suppression, the anti-offset piston structure improves the efficiency of converting electric energy into mechanical energy and optimizes of compression thermodynamic cycle. The experimental results can provide important references for the development of piston offset suppression strategies.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"153 ","pages":"Article 104251"},"PeriodicalIF":2.1,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682048","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":"Influence of eccentric field cooling on levitation and guidance performance of HTS maglev based on Halbach-type PMG","authors":"Yiming Zhou ,&nbsp;Boyi Zhao ,&nbsp;Yuchen He ,&nbsp;Zhichuan Huang ,&nbsp;Zigang Deng ,&nbsp;Weihua Zhang","doi":"10.1016/j.cryogenics.2025.104250","DOIUrl":"10.1016/j.cryogenics.2025.104250","url":null,"abstract":"<div><div>In practical research of high-temperature superconducting (HTS) maglev, a compulsory centering alignment operation between the superconducting levitator and permanent magnet guideway (PMG) is completed before field cooling (FC) process. However, errors in installation, positioning, and machining may lead to an eccentric state between the superconducting levitator and PMG before the FC process, which essentially means the geometric center of the internal HTS bulks is eccentric from that of the PMG. Therefore, this study investigates the effects of eccentric field cooling (EFC) on the levitation and guidance performance of HTS maglev. Specifically, a Halbach-type PMG is employed, and the eccentric displacement (ED) of bulks is set before FC process. Then during the levitation process, lateral displacement (LD) between bulks and PMG is applied to generate the guidance force. Results show that the EFC can adversely affect the levitation force, and this detrimental effect intensifies with increasing ED. During the LD process, when LD and ED are in the same direction, the reduction in levitation force increases with higher LD; conversely, when LD and ED are in opposite directions, the reduction decreases with increasing LD. Regarding the guidance force, at the initial of LD, appropriate EFC can enhance it, but excessive ED or LD values will negatively impact guidance force. These findings suggest that, in applications requiring high levitation performance, strict centering alignment operation before FC is essential. In contrast, for systems prioritizing guidance performance, appropriate applied EFC may be an effective optimization strategy.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"153 ","pages":"Article 104250"},"PeriodicalIF":2.1,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145616144","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":"VOF and sharp interface CFD analyses of a liquid methane self-pressurization experiment in 1 g and microgravity","authors":"Mohammad Kassemi ,&nbsp;Sonya Hylton ,&nbsp;Olga Kartuzova ,&nbsp;Daniel Hauser","doi":"10.1016/j.cryogenics.2025.104243","DOIUrl":"10.1016/j.cryogenics.2025.104243","url":null,"abstract":"<div><div>This paper presents a Computational Fluid Dynamics (CFD) study of tank self-pressurization during the storage of liquid methane in the Robotic Refueling Mission-3 (RRM3) microgravity experiment, where the pressure was controlled via active cooling. The RRM3 Experiment collected over 4 months of valuable microgravity data regarding the cryogenic storage and transfer of liquid Methane (LCH4) under Zero-Boil-Off (ZBO) conditions. The present study focuses on the donor (or source) Dewar that contained 50 L of cryogenic methane which was preserved using an active cryocooler. Two-phase axisymmetric Sharp-Interface (SI-CFD) and VOF (VOF-CFD) models, which were previously validated and anchored against the 1g cryogenic data which was available from NASA’s large tank experiments, and against 1g and microgravity simulant fluid data which was provided by the recent Zero-Boil-Off Tank (ZBOT) experiment, are employed here to study the self-pressurization segment of the RRM3 experiment during both ground-based and on-orbit tests. The validations of the two models against the 1g RRM3 experimental results indicate an excellent agreement between the predicted and measured tank pressure rise and the fluid and wall temperature evolutions. However, similar comparisons for the microgravity self-pressurization experiment indicate that, while the axisymmetric SI-CFD and VOF-CFD models both predict the rate of self-pressurization with good fidelity, the rate and magnitude of the wall temperature rise are significantly over-predicted and the rate and magnitude of the liquid temperature rise are considerably underpredicted by the SI-CFD model. On the other hand, the VOF-CFD model provides close agreements with both the measured rate of self-pressurization and the experimental evolution of the wall and liquid temperatures during the microgravity test. The VOF-CFD model’s good agreement with the measured wall temperatures is, however, attributed to a nonintuitive forced convection produced by an oscillatory interfacial movement during the VOF microgravity simulation. Since there is a great likelihood that the oscillatory interfacial motion is a numerical artifact, future work will focus on other mechanisms for the enhancement of the wall heat transfer in the RRM3 Donor tank for complete validation. CFD predictions of the whole field volume fraction and fluid temperature distributions, and of the fluid velocity vector fields, are presented and discussed to explain the self-pressurization behavior of the RRM3 tank predicted by the CFD model compared to the experiment. Finally, detailed energy distributions predicted by the SI-CFD model and the numerical predictions of a one-dimensional homogeneous thermodynamic model are also presented in order to gain a better understanding of the evolution of the energy distribution in the tank and to explain the nonintuitive self-pressurization behavior of the RRM3 tank in 1 g and microgravity.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"153 ","pages":"Article 104243"},"PeriodicalIF":2.1,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145616094","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":"Design and optimization of cryogenic helium extraction process based on AR-MRC cogeneration of LNG","authors":"Rong Ge Xiao ,&nbsp;Pei Jin Li","doi":"10.1016/j.cryogenics.2025.104239","DOIUrl":"10.1016/j.cryogenics.2025.104239","url":null,"abstract":"<div><div>Helium is a critical strategic scarce resource primarily extracted from natural gas. With rapid industrial development, China’s demand for natural gas and helium has surged dramatically. To address the natural gas supply–demand imbalance and achieve domestic helium production, a combined process was proposed integrating AR-MRC-based natural gas liquefaction with cryogenic helium extraction. The integrated process was simulated using HYSYS software. Through analysis of key parameter influences, a PSO-SVM prediction model was established. NSGA-II was employed for multi-objective parameter optimization of the improved process, yielding a Pareto solution set. The Pareto solution set was compared using the TOPSIS method, yielding optimal parameters: helium extraction tower feed pressure of 2573.08 kPa, helium extraction tower feed temperature of −57.57 °C, mixed refrigerant high-pressure of 2752.31 kPa, mixed refrigerant low-pressure of 87.44 kPa, mixed refrigerant flow rate of 755.35 kmol/h, first-stage separator feed temperature of −131.38 °C, and second-stage separator feed temperature of −178.96 °C. The selected optimal process performance metrics and corresponding operational parameters were validated using HYSYS software. The optimized process achieved total energy consumption of 10,177.48 kW, while the software calculation yielded 10,056.00 kW, with an error of 1.190 %. The optimized LNG liquefaction rate was 99.57 %, compared to the software result of 99.52 %, with an error of 0.050 %. The optimized helium concentration was 63.24 %, versus the software result of 63.18 %, with an error of 0.095 %. These results demonstrate that the optimized cogeneration LNG and natural gas liquefaction process indicators and corresponding operating parameters meet the expected requirements. The new cogeneration process exhibits favorable economic viability and can provide valuable reference for natural gas liquefaction and natural gas helium recovery cogeneration projects.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"153 ","pages":"Article 104239"},"PeriodicalIF":2.1,"publicationDate":"2025-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145578335","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":"Comparative analysis of Tb and Zn doping effects on the microstructural and mechanical properties of YBCO-123 and YBCO-358 superconductors","authors":"O. Ozturk ,&nbsp;G. Güdücü ,&nbsp;E. Asikuzun Tokeser ,&nbsp;S. Kurnaz ,&nbsp;T. Seydioglu ,&nbsp;G. Yildirim ,&nbsp;S. Safran","doi":"10.1016/j.cryogenics.2025.104236","DOIUrl":"10.1016/j.cryogenics.2025.104236","url":null,"abstract":"<div><div>In this study, the microstructural and mechanical properties of copper-based superconducting systems synthesized via the sol–gel method-namely Y_1-xTb_xBa₂Cu₃O_7-δ, Y₁Ba₂Cu_3-xZn_xO_7-δ, Y_3-xTb_xBa₅Cu₈O_18-δ, and Y₃Ba₅Cu_8-xZn_xO_18-δ were comparatively investigated to evaluate the effects of varying concentrations of terbium (Tb) and zinc (Zn) dopants on the structural integrity, crystal quality, and micromechanical strength of both Y_1-xTb_xBa₂Cu₃O_7-δ and Y_3-xTb_xBa₅Cu₈O_18-δ superconducting phases. X-ray diffraction (XRD) assessed crystal structure, phase purity, and dopant effects, while scanning electron microscopy (SEM) characterized particle size distribution, surface morphology, porosity, and potential phase separation. Vickers microhardness (H_v) testing quantified micromechanical behavior under varying dopant concentrations. Results show that Zn and Tb substitutions influence crystal structure and mechanical strength differently depending on dopant level and superconductor type. Optimized doping enhanced phase purity, lattice stability, microstructural coherence, and hardness, whereas excessive doping caused lattice distortions, defect clustering, oxygen ordering instabilities, and partial phase separation. Y_1-xTb_xBa₂Cu₃O_7-δ ceramics exhibited superior tolerance to both dopants, with improved crystallinity, grain connectivity, and mechanical robustness at higher concentrations. In contrast, the Y_3-xTb_xBa₅Cu₈O_18-δ ceramic structure was more sensitive to doping, showing benefits only at low levels and significant structural degradation at higher levels, explaining the preference for the Y_1-xTb_xBa₂Cu₃O_7-δ phase in substitution studies. Analysis of load-independent Vickers hardness in plateau regions indicated that the Indentation-Induced Cracking (IIC) model most accurately described mechanical behavior. Consequently, precise optimization of dopant type and concentration is essential to achieving high structural integrity and mechanical performance, making these YBCO-based superconductors promising candidates for advanced energy and technological applications.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"152 ","pages":"Article 104236"},"PeriodicalIF":2.1,"publicationDate":"2025-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145568228","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":"Influence of gas impurities on high-accuracy refractive index gas thermometry","authors":"Guoxin Li ,&nbsp;Yaonan Song ,&nbsp;Haiyang Zhang ,&nbsp;Xiangjie Kong ,&nbsp;Siqi Liu ,&nbsp;Wenxiang Guo ,&nbsp;Bo Gao","doi":"10.1016/j.cryogenics.2025.104238","DOIUrl":"10.1016/j.cryogenics.2025.104238","url":null,"abstract":"<div><div>Refractive index gas thermometry (RIGT) is a primary method for high-accuracy thermodynamic temperature measurements, yet the precise quantification of impurity-induced effect, especially at temperatures below 25 K, has remained a challenge. To address this, we present a comprehensive numerical approach to evaluate impurity-induced relative temperature deviations <em>δ</em> in RIGT. This approach is applied to systematically investigate such deviations for three monatomic working gases (Ne, ⁴He, and ³He) over wide ranges of temperature (1.5 K − 273.16 K), pressure (0.3 kPa − 250 kPa) and impurity concentration (0.05 ppm − 5 ppm). Our results indicate that the maximum relative temperature deviations are 2.4 ppm for Ne, 0.33 ppm for ⁴He and 0.45 ppm for ³He. A key finding is that while the existing mixture <em>A</em>_<em>ε</em> model remains valid at higher temperatures, accurate impurity correction under cryogenic conditions requires consideration of the second virial coefficient. We demonstrate that these two parameters collectively explain nearly 100 % of <em>δ</em> across the full temperature ranges, making the simplified <em>A</em>_<em>ε</em> + <em>B</em> model as an efficient and accurate alternative to the full-scale computations. This work provides a robust theoretical framework for quantifying impurity-related uncertainties and offers practical guidance for optimizing gas-handling systems for high-precision primary gas thermometry. Further refinement of the model will be feasible with the future availability of high-accuracy <em>ab initio</em> virial coefficients for gas mixtures.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"152 ","pages":"Article 104238"},"PeriodicalIF":2.1,"publicationDate":"2025-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145568229","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":"Development of cryogenic DTE-type heat switch at 100 K for space application","authors":"Priyavardhan Patel ,&nbsp;Anjan Patel ,&nbsp;Jitaksha Gajjar ,&nbsp;Surendra Singh Sisodia ,&nbsp;Vivek Kumar Singh ,&nbsp;Sandip R Somani ,&nbsp;R.R. Bhavsar","doi":"10.1016/j.cryogenics.2025.104240","DOIUrl":"10.1016/j.cryogenics.2025.104240","url":null,"abstract":"<div><div>Heat switches are commonly used in space applications to thermally isolate sensitive detectors during high-temperature decontamination processes, protecting them from potential damage. They are also employed to ensure cryocooler redundancy by allowing selective thermal connection or disconnection, which enhances system reliability throughout the mission.</div><div>However, passive actuation heat switches often face challenges such as limited switching speed, sensitivity to environmental variations, and difficulty in precise control of the switching temperature.</div><div>To address these challenges, we are developing an actively actuated DTE-type heat switch with a weight of 200 g, designed to operate at 100  K with a 102  μm gap between the connecting interfaces. Different materials with distinct physical properties were selected to ensure optimal performance. Ultem 1000 was used for its high coefficient of thermal expansion (CTE), which plays a critical role in bridging the 102  μm gap during actuation.</div><div>A detailed thermo-structural simulation was carried out, followed by experimental validation. The simulated switching ratio achieved was 182. In the OFF state, the thermal resistance was measured experimentally as 77.2 °C/W, compared to 80.11 °C/W in simulation. In the ON state, the thermal resistance was 1.63 °C/W experimentally and 0.56 °C/W in simulation. This design combines simplicity, a wide operational range, an appropriate switching ratio <span><math><mrow><msub><mrow><mo>(</mo><mi>γ</mi></mrow><mrow><mi>switch</mi></mrow></msub><mrow><mo>)</mo></mrow></mrow></math></span>, and a switching time constant (<span><math><mrow><mi>τ</mi></mrow></math></span> _switch), making it an attractive solution for cryogenic thermal management in spaceborne sensor and cryocooler systems.</div></div>","PeriodicalId":10812,"journal":{"name":"Cryogenics","volume":"152 ","pages":"Article 104240"},"PeriodicalIF":2.1,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145568231","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}