bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Study and Improvement of Pressure Degradation of Helium Cryogenic System at NSRRC
Authors: Tsai H. H. , Hsiao F. Z. , Chuang P. S. , Li H. C. , Liao W. R. , Chiou W. S. , Chang S. H. 
Published: July 2024

Abstract
This paper is aimed at studying and improving the phenomenon of pressure degradation in a helium cryogenic system. There are two 450W helium cryogenic systems for the Taiwan light source (TLS) and one 890W helium cryogenic system for the Taiwan photon source (TPS) housed at the National Synchrotron Radiation Research Center (NSRRC). The TLS helium cryogenic system is used for one superconducting radio frequency (SRF) cavity and five superconducting magnets. The TPS helium cryogenic system is used for two SRF cavities at the present stage. These three helium cryogenic systems have experienced pressure degradation, which reduced their performance and increased liquid nitrogen consumption for precooling over the past few years. A cryogenic adsorber was set up in an effort to capture the impurities, but this made no difference for pressure degradation in the system. The impurities were comprised of not only gas but also moisture. It was found that the cryogenic adsorber was not efficient enough to remove the moisture. This paper presents the study for the phenomena of pressure degradation. A moisture removal system was designed which is also discussed.
PIP-II cryoplant non thermal cycling updates
Authors: Creus-Prats J , Soyars W , Dhuley R , Martinez A , Hansen B , Jia Y , Wielgos R , Chakravarty A , Goyal M 
Published: July 2024

Abstract
The Proton Improvement Plan-II (PIP-II) is a crucial upgrade to the Fermilab accelerator complex, featuring a new 800-MeV Superconducting Radio-Frequency (SRF) linear accelerator (LINAC) with 23 cryomodules operating at 2 K. The LINAC thermohydraulic conditions are satisfied by the cryogenic subsystems: Cryogenic Distribution System (CDS), a helium refrigerator cold box (CB), a warm compression station (WCS) and a helium recovery system (RSYS). The accelerator has a strict requirement of non-thermal cycling of the LINAC cryomodules during planned and unplanned subsystem outages. This paper presents an integrated reliability analysis of the PIPII cryoplant. The study evaluates both normal and abnormal operating modes, with a focus on identifying integrated scenarios that put subsystems components under stress. The conclusions of this study will help build redundancy to mitigate LINAC thermal cycling risks during planned and unplanned subsystem outages.
Process design for FRIB’s experimental refrigeration system
Authors: Hasan N , Ganni V , Knudsen P , Casagrande F , Howard J 
Published: July 2024

Abstract
The experimental system (ES) for the Facility for Rare Isotope Beams (FRIB) at Michigan State University (MSU) has several segments. Following the acceleration through the three superconducting LINAC segments, the heavy ion beam is guided through the target, a fragment pre-separator and (the A1900) separator segments. There are many beam lines and then it can be split and sent to various experimental vaults and instrumentation, e.g. S800 spectrograph, and the newly proposed High Rigidity Spectrometer (HRS). Presently, superconducting magnets at the target and fragment pre-separator segments, along with the LINAC superconducting cryo-modules, are supported by FRIB’s main central helium liquefier/refrigerator (CHL). The remainder of the cryogenic loads are supported by the legacy NSCL Cryogenic Refrigerator (a re-commissioned Bureau of Mines helium liquefier from the mid 1970’s) and has many obsolete components for reliable operation. Considering the operational reliability of the accelerator, maintainability of the entire cryogenic system at FRIB and ever-growing experimental beam lines – it is logical to segregate the experimental system loads from the accelerator system loads. A new 4.5 K refrigerator along with a thermal shield (55 K) refrigerator are planned to support the operation of these experimental system (ES) loads and make plans for the CHL maintenance. These refrigerators will be able to support a combination of 4.5 K isothermal refrigeration, 4.5 K liquefaction (for magnet lead cooling and transients) and thermal radiation shield loads. The design loads, modes of operation and the planned operation of the FRIB cryogenic system with these refrigeration systems are discussed. This paper outlines the key selection parameters and design modes for the major components, such as the warm compressors, turbo-expanders and heat exchangers.
Modelling and optimization of cryogenic mixed-refrigerant cycles for the cooling of superconducting power cables
Authors: Boehm F , Grohmann S 
Published: July 2024

Abstract
For the green energy transition, the transport of large amounts of electrical energy is needed both in densely populated areas and over long distances. Superconducting power cables represent one possible solution, requiring energy-efficient liquid nitrogen re-cooling stations for an economical operation at cable lengths longer than about 1 km to 2 km.
In this contribution, a model for simulating cryogenic mixed-refrigerant cycles (CMRC) based on the Joule-Thomson effect and an associated optimization algorithm are presented. The distinctive feature of CMRC is the combination of good scalability of the cooling capacity, adaptability of the mixture to the specific application and an inexpensive process design. While the process is relatively simple, the identification of ideal operating conditions and mixture compositions requires complex modelling. In order to optimize these characteristics for CMRC processes, the Differential Evolution algorithm is adapted to a model built in Mathematica. Thermodynamic property data is calculated with the Peng-Robinson Equation of State as part of CoolProp, an open-source thermophysical property library. First simulation results are presented and further improvements are being discussed.
Development of Brayton circulating cooling system
Authors: Gandla S K , Longsworth R C , Sloan R B 
Published: July 2024

Abstract
The Brayton Circulating Cooling System is a unique refrigeration system designed to demonstrate the basic technology needed to provide cold helium gas refrigeration at high pressures to an external superconducting magnet or any remote load for cool down purposes. The system is designed to provide cool down refrigeration from room temperature to target minimum temperatures of approximately 40 K. The system consists of an F-70H helium compressor with gas control manifold, interconnecting gas lines, cables, the Brayton refrigeration unit mounted in a Dewar assembly and control system. The helium compressor uses high purity helium gas for its refrigerant. Electricity, cooling water for the compressor and a source of pure helium (99.995%) for make-up gas are the only required utilities. The scope of the project, system design, target specifications and summary of test results will be discussed in this paper.
Design and performance of the J-T component of dry dilution refrigerator
Authors: Zheng Maowen , Pan Zijie , Wei Lingjiao , Quan Jia , Wang Guopeng , Liang Jingtao , Li Ruixin , Hong Guotong 
Published: July 2024

Abstract
An effective J-T component is crucial for the operation of dilution refrigerator due to its function as a 3He liquefier in a refrigeration cycle. This paper briefly introduces the principle of the J-T component in dry dilution refrigerator, studies the influence of J-T component on the still and its design method. An effective J-T component is designed to cool over 3 K of 3He gas to almost 1 K of 3He liquid. The basic still temperature is below 0.5 K in a dilution refrigerator prototype. In this prototype, a two-stage step heat exchanger was adopted to obtain the lowest temperature below 26 mK.
Development of a 5 W/4.2 K two-stage pulse tube cryocooler
Authors: Hao X , Zerkle B , Cosco J , Dausman R 
Published: July 2024

Abstract
The 2.7 W/4.2 K two-stage pulse tube cryocooler (Model PT425) was developed and introduced by Cryomech, Inc. in 2021, which, at the time, was the largest, commercially available, 4 K pulse tube cryocooler. Our newest model, the PT450, has been successfully developed, providing a minimum of 5.0 W at 4.2 K on the 2nd stage with 65 W at 45 K on the 1st stage simultaneously, operating on either 60 or 50 Hz power. The PT450 answers the market’s need for the continuing development of large cryogen-free dilution refrigerators, superconducting magnets, helium liquefiers and other applications requiring large cooling capacities at 4 K.
In addition, a new helium compressor (Cryomech CPA3027) has also been developed to provide sufficient helium flow for the PT450 and other large cooling power cryocoolers. This new model also allows multiple cryocoolers to operate on one compressor. The CPA3027 is the largest commercially available helium compressor for the Gifford-McMahon and pulse tube cryocooler market.
The system configuration and main cooling performance of the PT450 cold head will be presented in this paper.
Cooling power analysis of a small scale 4 K pulse tube cryocooler driven by an oil-free low input power Helium compressor
Authors: Schmidt J-A , Schmidt B , Falter J , Höhne J , Dal Savio C , Schaile S , Schirmeisen A 
Published: July 2024

Abstract
Here we report the performance of a small scale 4 K pulse tube cryocooler operating with a low input power reaching a minimum temperature of 2.2 K, as well as a cooling capacity of over 240 mW at 4.2 K. The compressor is air cooled and can be supplied by single phase power sockets. With an input power of about 1.3 kW the coefficient of performance reaches values of up to 185 mW/kW, which is among the highest currently reported values for small to medium power pulse tubes. The combination of an oil-free Helium compressor and low maintenance pulse tube cryocooler provides a unique miniaturized, energy efficient and mobile cooling tool for applications at 4 K and below.
Study on a 20 K two-stage thermally-coupled pulse tube cooler with independent ambient displacers
Authors: Ding X.P. , Li Z.K. , Wang X.T. , Zhang Y.B. , Dai W. , Li H.B. 
Published: July 2024

Abstract
Pulse tube cooler has the advantages of higher reliability and longer MTTF compared to Stirling cooler due to the elimination of moving components at the cold end. Pulse tube cooler working at liquid hydrogen temperatures has already become a strong candidate in sensor cooling, high-temperature superconductivity, etc. However, the efficiency of the pulse tube cooler at liquid hydrogen temperatures remains relatively low. In this paper, a two-stage thermally-coupled Stirling-type pulse tube cooler working at liquid hydrogen temperatures is designed and simulated. The first and second stage use independent ambient displacers as phase shifters. The simulation results show that the pulse tube cooler can reach a higher relative Carnot efficiency due to the improvement of the phase distribution of the whole system by using independent displacers. Meanwhile, the influence of factors such as average pressure and operating frequency on the system performance is also discussed.
Accelerator magnet development based on COMB technology with STAR® wires
Authors: Kashikhin V V , Cohan S , Lombardo V , Turrioni D , Mai N , Chavda A K , Sambangi U , Korupolu S , Peram J , Anil A , Goel C , Sai Sandra J , Yerraguravagari V , Schmidt R , Selvamanickam V , Majkic G , Galstyan E , Selvamanickam K 
Published: July 2024

Abstract
This paper reports progress in the development of COMB magnet technology with STAR® wires. A two-layer dipole magnet with 60 mm clear bore has been recently fabricated and tested in liquid nitrogen. The purpose of the test was to determine what kind of critical current degradation occurs in the process of winding the STAR® wire into the COMB structure.
Reengineering the RHIC helium cooled current leads for EIC
Authors: Micolon F , Bruno D , Mi C , Holmes D , Lambiase B , Than R , Tuozzolo J 
Published: July 2024

Abstract
The electron ion collider (EIC) Hadron Storage Ring (HSR) will reuse most of the existing superconducting magnets (SC) from the RHIC storage ring. However, for some sectors of the machine, a modification of the accelerators optics will be required. To do this, the existing RHIC magnet electrical circuits will have to be modified and some superconducting current leads will need to be used at higher current. A work has been conducted to understand the current leads design parameters and their operational flexibility around these parameters, in particular for use at higher current.
This paper details the study of the existing RHIC current leads, their potential for use at higher current and where required the modifications to extend their operational range.
Exergy analysis and improvement of helium internal purifier
Authors: Du J J , Li Z Y , Liu L Q , Gong L H , He M 
Published: July 2024

Abstract
Exergy analysis was applied to the evaluation of helium internal purifier in this paper. The important operating parameters has been given to determine the exergy destructions in components as well as in the entire cycle of internal purifier. The analysis results show that the recovery of liquefied air energy can improve the performance of purifier and the exergy destruction of different heat exchanger is different. Results from the analysis helped evolving guidelines for designing appropriate technological process for practical helium internal purifier. An internal purifier with an optimized structure was designed to remove air impurities up to 10 mol%, beyond previous maximum impurity content. The impact on liquefaction capacity is minimized because of the small consumption of cold flow. The achievable performance was also provided in this paper. The purifier could remove air impurities up to 8 mol%.
Experimental study of two-phase cryogenic cooling of aluminum stator conductors using a single slot test configuration
Authors: Guo Y , Majoros M , Cantemir C G , Kwon J , Kovacs C , Rindfleisch M , Tomsic M , Doll D , Sumption M , Collings E W 
Published: July 2024

Abstract
An important goal to enable widespread adoption of electric aircraft propulsion is to develop higher power density motors and generators which are at the same time highly efficient. One way to do this is to use conductors that can carry higher currents and/or generate lower losses. One approach to this is the use of superconducting windings. However, here we focus on very low resistance normal state conductors operating at cryogenic temperatures. The resistivity of both aluminum and copper drops quickly with decreasing temperature, such that the resistivity of Cu drops by about a factor of 7, and that of aluminum by 10, by the time we reach 77 K (LN2). OSU and Hyper Tech have teamed to develop a motor with liquid cryogen cooled aluminum windings (LN2 or LNG cooled). It includes a multi-slot stator with direct cryogen cooling. Here we present the results of a simple “single slot” test which explores the temperature rise of a pair of conductors in a slot directly cooled by LN2. These two aluminum bars are made of 1100 commercial purity Al alloy were placed in parallel with a 1.6 mm gap, which behaved as 120 mm long cryogenic flow channel. Current densities up to 75 A/mm2 were explored, with LN2 flow rates ranging from 1.9 g/s to 6.4 g/s. Thermocouples and voltage taps were used to capture temperature and voltage data during the experiment. As a result, we found stable cooling and operation at these flow rates and current densities, and we characterized the temperature gradient which developed along the conductor bars.
Validation of Universal Cryogenic Flow Boiling Correlations in Thermal Desktop for Liquid Helium
Authors: Tesny Erin , Hartwig Jason , Ganesan Vishwanath , Mudawar Issam , Mercado Mariano , Johnson Brian 
Published: July 2024

Abstract
Understanding two-phase cryogenic propellant behavior is key to enabling technologies for future spaceflight missions. Developing accurate models of two-phase flow phenomena, particularly in the current work, flow boiling in the heating configuration, is relevant to the propellant transfer process both in 1-g and microgravity. Currently there is a need for more accurate, direct cryogenic data anchored models for various boiling phenomena. Recently, universal correlations for cryogens flowing in heated tubes have been developed for a wide variety of fluids, thermodynamic conditions, and various regimes across the boiling curve, and have been patched to provide a smooth, continuous predictive curve. This paper describes implementation and validation of these correlations into Thermal Desktop to improve predictive performance, with a focus on liquid helium. Results from Thermal Desktop using both the built-in and new correlations are validated against a historical dataset of flow boiling experiments in the heating configuration using liquid helium. Based on results, the new correlations show a substantial improvement over the original built-in flow boiling correlations in Thermal Desktop in predicting the wall temperature as a function of preponderant parameters for this quantum fluid at temperatures greater than the lambda temperature, T
λ = 2.17K.
Critical heat flux of liquid hydrogen, liquid methane, and liquid oxygen: a review of available data and predictive tools
Authors: Baldwin Michael , Ghavami Ali , Mostafa Ghiaasiaan S. , Majumdar Alok 
Published: July 2024

Abstract
Available experimental data dealing with critical heat flux (CHF) of liquid hydrogen (LH2), liquid methane (LCH4), and liquid oxygen (LO2) in pool and flow boiling are compiled. The compiled data are compared with widely used correlations. Experimental pool boiling CHF data for the aforementioned cryogens are scarce. Based on only 25 data points found in five independent sources, the correlation of Sun and Lienhard (1970) is recommended for predicting the pool CHF of LH2. Only two experiments with useful CHF data for the pool boiling of LCH4 could be found. Four different correlations including the correlation of Lurie and Noyes (1964) can predict the pool boiling CHF of LCH4 within a factor of two for more than 70% of the data. Furthermore, based on the 19 data points taken from only two available sources, the correlation of Sun and Lienhard (1970) is recommended for the prediction of pool CHF of LO2. Flow boiling CHF data for LH2 could be found in seven experimental studies, five of them from the same source. Based on the 91 data points, it is suggested that the correlation of Katto and Ohno (1984) be used to predict the flow CHF of LH2. No useful data could be found for flow boiling CHF of LCH4 or LO2. The available databases for flow boiling of LCH4 and LO2 are generally deficient in all boiling regimes. This deficiency is particularly serious with respect to flow boiling.
Optimization of thermoelectric generator power density for cryogen cold exergy recovery
Authors: Sierpowski K J , Gizicki W , Malecha Z M , Chorowski M 
Published: July 2024

Abstract
The article presents the optimization of the power density of a thermoelectric generator (TEG) operating in cryogenic temperature conditions. Optimization of TEG power density was performed as a function of TEG leg length and its effect on TEG performance. The figure of merit (ZT) of the TEG was experimentally verified for the temperature range of a cold sink from 160 to 250 K, which corresponds to the temperature of the wall subjected to the boiling film of LNG. The numerical model proposed in the article was verified by comparison with experimental data, and then used to simulate the operation of the TEG at a cold sink temperature of 80 K corresponding to the wall temperature in the process of LH2 regasification. The obtained results showed that the optimal length of TEG legs is less than 10 mm and depends on the boiling and heat transfer regime. The results of the presented research can be used to improve the effectivity of cold exergy recovery from cryogenic systems.
Thermal conductivity measurements for additively manufactured AlSi10Mg and Al6061-RAM2 Aluminum composites at cryogenic temperatures
Authors: Shenton M , Reising L , Leachman J 
Published: July 2024

Abstract
Advances in 3D printing are disruptive opportunities for material selection and component design in cryogenics. However, thermophysical property measurements for these novel materials are generally unavailable at cryogenic temperatures. This experiment explores the variation in thermal conductivities due to print direction of two aluminium composites (AlSi10Mg and Al6061-RAM). The direct linear heat flow method was utilized to calculate thermal conductivities using a measured wattage input, temperature differential, and Fourier’s Law of Conduction. A multi-measurement linear regression was applied to determine thermal conductivities at fixed average temperatures over the range of 20-100K. The AlSi10Mg composite had a greater thermal conductivity than Al6061-T6 for both printing planes by approximately 230%. The XY-plane print direction resulted in a reduction in thermal conductivity compared with the Z-plane by approximately 30%. The AL6061-RAM composite had effective thermal conductivities smaller than the machined Al6061-T6 by approximately 70% for both print directions. The thermal conductivity in the Z-plane print direction was consistently greater than the thermal conductivity in the XY print direction. Validation studies were conducted utilizing Al6061-T6 and SS-304/304L. The calculated deviation for the validation samples depicted a 20% difference from the National Institute of Standards and Technologies (NIST) recommended reference values. The calculated uncertainty of the experimental system was 5-10%, increasing as temperature decreased. These preliminary measurements depict the need for further analysis on 3D printed composite materials and reverification of common materials due to improvements in current manufacturing methods since the classic experimental measurements were carried out for SS-304/304L and Al6061-T6.
Cryogenic thermo-physical properties of additive manufactured materials
Authors: Weiss Klaus-Peter , Bagrets Nadezda , Schulz Camelia 
Published: July 2024

Abstract
Environmentally friendly aviation is one of the great challenges of this century. One promising approach is electric flight, in which an energy carrier (e.g. liquid Hydrogen LH2) and an electric powertrain work together. Within the scope of the joint project AdHyBau, the overarching goal is the development of new additive processes and fibre composite-metal hybrid designs for use in the cryogenic environment of such an electric propulsion system. Additive manufacturing of complex components for use in the cryogenic temperature range down to 20K (LH2) is one essential component in the production. For the design and optimization of the different components it is necessary to know the thermo-physical behaviour of such materials like high purity copper, Ti6Al4V alloy, Al-Mg-Sc alloy, and Inconell 718. The thermo-physical parameters investigated are thermal expansion, thermal & electrical conductivity and heat capacity. Further production-related influences coming from the method used (SLM, DED or Cold-Spray) and orientational dependences are discussed.
Supported by the Federal Ministry for Economic Affairs and Climate Action of the Federal Republic of Germany. Grant-No.: 20M1904D.