bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental and numerical investigation of self-pressurization with different methods of insulation for ground and space applications
Authors: Vishnu S B , Biju T K 
Published: June 2022

Abstract
The necessity of precise estimation and understanding of self-pressurization in a cryogenic storage vessel has increased rapidly over the years because of the influence of self-pressurization phenomena on the design of cryogenic engines. Since propellants are stored at their boiling temperature or subcooled condition, very small heat infiltration itself causes self-pressurization. When heat is transferred to the propellant tank, the liquid near the sidewall is heated up, and a warm stratified layer is developed at the liquid vapor interface, which causes self-pressurization. A numerical model is developed, and experiments are conducted to investigate the self-pressurization effects of cryogenic storage vessels to precisely understand the mechanisms causing it and the effect of methods of insulations, including multi-layer insulations in tanks. The numerical model is developed based on the available correlation to predict the self-pressurization and related parameters of a double wall cryogenic storage tank with different sets of insulations such as air, foam, vacuum, and MLI and different cryogens; hydrogen, nitrogen, and oxygen. A double wall cryogenic storage tank using SS 304 is also developed, conducted self-pressurization studies using liquid nitrogen under different methods of insulation. The experimental results were compared with the numerical model and found in good agreement. Comparing the self-pressurization rate of different cryogens, the value is higher for hydrogen. Since the boiling point of hydrogen is less, the axial heat flux acting will be higher. The low-density fluids will quickly move towards the interface and deposit, causing a warm layer at the liquid-vapour interface. The amount of phase change is also higher for liquid hydrogen, which in turn aid in rapid self-pressurization. Among the insulations used, multi-layer insulation shows the best performance in terms of thermal resistance. The analytical and heat transfer model developed predicts and compared well with the experimental results and can be used for a variety of situations in ground and space for self-pressurization and roll over phenomenon studies and prediction of results in advance.
Numerical investigation of two-phase fluid-transient induced cavitation in the cryogenic propellant feedlines
Authors: Garva A , Mishra A , Ghosh P 
Published: June 2022

Abstract
Rapid changes in fluid-flow conditions, whether purposeful or accidental, may result in generation of a pressure surge in the fluid handling equipment followed by oscillations of pressure, which is known as the fluid transient (or fluid hammer). Fluid transient occurs very often during the filling of the dry liquid lines as well as during the valving operation in the cryogenic propellant feed systems. The maximum amplitude of fluid transient induced pressure oscillations may exceed the strength of the material, which results in the rupture of the flow components. Sometimes, due to its oscillatory nature, when the pressure wave amplitude falls below the vapour pressure of the fluid it may lead to cavity generation resulting in two-phase fluid transients. The pressure generated due to the collapse of the cavity will be higher than the pressure in the single-phase fluid transients that may lead to the structural failure of the fluid handling equipment.
In this study, a one–dimensional numerical model has been proposed using the Method of Characteristics (MOC) scheme to investigate the fluid transient induced cavitation due to sudden closure of the valve in the propellant feedlines. Different two-phase models namely Discrete Vapour Cavity Model (DVCM) and Discrete Gas Cavity Model (DGCM) have been used to predict the vapour volume in the pipe. The applicability of the developed model has been evaluated by validating its predictions with the results available in the literature. It has been observed that both the models are in good agreement with experiments, but DGCM can be preferred due to its ability to handle larger void fractions as compared to DVCM.
Status and development trends of the space 2 K mechanical cryocooler
Authors: Liu Z Y , Ma Y X , Quan J , Liu Y J , Wang J , Li J G , Liang J T 
Published: June 2022

Abstract
The space 2 K cryogenic technology is one of the critical supporting technologies for deep-space explorations. With the development of space detectors, such as infrared and X-ray detectors, the demands for the space 2 K cryogenic technology have become much more urgent. Early space detection missions used superfluid helium cryostats (SHCs) to meet their requirements. However, cryostats have been gradually replaced by the 2 K mechanical cryocoolers due to the large volume, heavy weight, and short life of cryostats. Hybrid JouleThomson (J-T) cryocoolers are the best alternative to cryostats in the 2 K mechanical cryocoolers because of their relatively higher efficiency at 2 K. This paper provides an up-to-date review of space missions involving 2 K hybrid J-T cryocoolers and a summary on the key issues that need to be solved in the 2 K J-T cryocoolers.
Beam induced heat load instrumentation installed in LHC during the Long Shutdown 2
Authors: Bradu B , Brodzinski K , Casas-Cubillos J , Delikaris D , Deschamps J B , Le Naour S , Pezzetti M , Tavian L , Tovar A , Sisti M , Ph Tock J , Vauthier N 
Published: June 2022

Abstract
During the second run of the Large Hadron Collider (LHC) between 2015 and 2018, significant beam induced heat loads have been observed on the beam screens circuits impacting the cryogenic system capacity, mainly due to the electron clouds generated by the beams. To validate these measurements and to obtain precise heat load assessments and comparison with preliminary calculations based on existing hardware equipment at selected locations, it was decided to add new cryogenic instrumentation around the machine. In total, 23 Coriolis flowmeters (cold conditions), 4 thermal flowmeters (room temperature conditions) and 58 Cernox thermometers have been installed and commissioned between 2019 and 2021 during the so-called long shutdown 2 (LS2). This paper presents an overview of this project, including the commissioning of these instruments and confirming at first stage the original heat load estimations.
Drawn-polymer recuperative heat exchangers for use in cryocoolers
Authors: Adams J L , Thompson K J , Cummings J , Cantley L , Brisson J G 
Published: June 2022

Abstract
Polymer microchannel heat exchangers for use in cryocooler applications have been developed. These heat exchangers are manufactured using a thermal drawing process where a bulk polymer preform is heated and stretched. The process results in channels with a characteristic dimension of 50-100 µm and with an overall length of many meters. The drawn heat exchangers are lightweight, flexible, and have a large surface-area-to-volume ratio. Initial tests on a Joule-Thomson cryocooler with a heat exchanger of overall dimension of 2.5mm x 2.5mm x 420mm with nitrogen as a working fluid were performed. Nitrogen was successfully liquified with a mass flow rate of 34 mg/s and cooling power of 200 mW at 80 K.
Remote cooling systems with mesh-based heat exchangers for cryogenic applications
Authors: Onufrena A , Naydenov B , Koettig T , Bremer J , Tirolien T , ter Brake H J M 
Published: June 2022

Abstract
In the refrigeration technologies available for the 2 W - 5 W cooling power range at 4.5 K, innovative designs for intermediate cooling options are proposed between the large-scale cryogenic plants and small-scale commercially available cryocoolers. This paper presents a number of remote cooling solutions, which use high-effectiveness mesh-based counterflow heat exchangers (CFHEX) to support the aforementioned refrigeration domain. Additionally, the cooling power is aimed to be provided in a remote, distributed and non-disturbing manner (i.e. reduced mechanical vibrations and magnetic disturbances) for high-technology cryogenic applications that require very low background noise levels. The proposed remote cooling options are analysed in terms of their cooling power performance. Designs and sizing of individual system components, i.e. CFHEXs and cooling interface options, for superconducting radio frequency (SRF) cavity cooling application are also proposed. CFHEX compactness and influence of their individual effectiveness values on the performance of the remote cooling systems are assessed, and capillary cooling interface performance is analysed.
Design and performance analysis of the thrust gas bearing with single orifice for helium turbine
Authors: Li S S , Fu B , Zhang Q Y , Chen S X 
Published: June 2022

Abstract
Thrust bearing is an important component for the stability of helium turbo-expander, and is a critical part to ensure the stable operation of helium refrigerator. A thrust bearing with single orifice is designed at the end of the fan brake for a home-made 500W@4.5K helium turbine. This design optimizes the mechanical structure of the rotor and improves the overall stability of the helium turbine. To increase the axial capacity, the static and dynamic calculation model of this thrust bearing is established to analyse the performance. This paper describes the variation curve of parameters and studies the influence of temperature on bearing performance by numerical simulation method. The analysis as more simple and efficient method is used to obtain the important parameters of this thrust gas bearing with single orifice, which meets the demand of the whole engineering design for helium turbine expander.
Effect of trailing edge bending and sweeping on brake impeller of low-temperature turbo-expander
Authors: Liang Y W , Peng N , Li K R , Ke C L , Li J , Dong B , Yan H , Zhang X H , Zheng L W , Xiong L Y , Liu L Q 
Published: June 2022

Abstract
With the continuous development of low-temperature turbo-expanders, the rotation speed of the rotor is getting faster. The diameter of the impeller has become one of the factors that limit the rotation speed. In this article, a new idea to improve braking capability and reduce the diameter of the brake impeller is proposed. The brake impeller of a small low-temperature air turbo-expander test bench is used as a prototype, influence of the combination of circumferential bending and sweeping at the trailing edge of the brake impeller on the braking ability is studied. It is found that the braking ability is significantly improved. To simplify the description, the combination of a forward bending of 10° and a sweeping of 20° is called combination 1. For the current brake impeller, combination 1 is the most suitable. Compared with the original impeller, the braking power of combination 1 has increased by 99.6 W, an increase of 10.4 %. Forward bending and forward sweep substantially increase the wrap angle of the brake impeller, thereby increasing the air outlet speed and improving the braking ability, but at the expense of the flow stability of the brake impeller.
Research on the thermal performance of a heat exchanger with meso-scale twisted helical tube bundles
Authors: Wang Y N , Pfotenhauer J M , Miller F K 
Published: June 2022

Abstract
Heat exchangers with helical tubes are applied widely in various industrial fields and cryogenic applications. Currently, the most common ones are the spiral wound heat exchangers, which consists of many layers of spiral tubes with different coil diameters in a closed shell. Most of the fluid in the shell-side passes directly through the gap between two adjacent layers, which weakens the turbulence and the associated heat transfer coefficient. A novel twisted helical bundle geometry is proposed in this paper of which the thermal performance is explored using CFD simulation. The heat exchanger uses helium gas as the working fluid and operates between 300 K and 30 K. The curve of each tube in the bundle is generated by different 3D sinusoidal equations, and the tubes at adjacent layers are twisted together thereby producing the same end-to-end length for each tube. By simulating a spiral wound heat exchanger using different turbulent equations and comparing the results with experimental data from literature, the k-omega SST model is found to be the most suitable one to simulate this kind of geometry. Nusselt numbers and friction factors are obtained under different Re values and compared with those of standard spiral wound heat exchangers. The creative twisted geometry can improve the Nu number although also increasing the friction factor. Geometry parameters such as pitch length are being further explored to obtain an optimal thermal performance.
Testing and analysis of stand-by operating modes for FRIB helium refrigeration system
Authors: Kroll D , Howard J , Knudsen P , Hasan N , Ganni V 
Published: June 2022

Abstract
The main helium refrigeration system at FRIB is designed for a maximum capacity of 180 g/s (30K, 1.16 bar) cold compressor return flow, 14.0 g/s of 4.5 K liquefaction load, 4.0 kW 4.5 K refrigeration load and a 20.0 kW (35 – 55 K) thermal shield load. The helium refrigeration system operates using the Ganni Floating Pressure process and can adjust to a range of variable cryogenic load conditions without any artificial loads. It is designed considering long-term 24/7 support for the loads (cryostats and superconducting magnets) maintained at 4.5 K, without the need for a complete warm-up to room temperature. A number of maintenance, repair and outage scenarios, and the corresponding stand-by operating modes for the refrigeration system with the base-line cryogenic load have been considered, tested and analysed. This paper reports an overview of these stand-by modes and the associated analysis.
Reconstruction and operation of the helium purification system in the cryogenic system for EAST Tokamak
Authors: Zhou Z W , Zhang Q Y , Zhu P , Wu K P , Zhu Z G , Sheng L H , Yuan K 
Published: June 2022

Abstract
EAST (Experimental Advanced Superconducting Tokamak) cryogenic system has participated in the physical experimental campaigns over 15 years since the first cool-down experiment in 2006. Some fault of the heat exchanger blocking due to the purification of gas helium has occurred several times during the cryogenic system’s operation since 2017, which caused the system warmed up to deal with the malfunction. Therefore, the helium gas purification system including the oil-removal system after the oil-injected screw compressors, the adsorbers inside the cold-box and two sets of external purifiers as well as the control system has been redesigned and reconstructed from 2019 to 2020, and put into operation in the 18th cool-down experiment of EAST cryogenic system at the beginning of 2021. The process flow of new helium purification system and the equipment parameters together with the reconstruction process will be presented in detail in this paper. Meanwhile, the commissioning operation results will be illustrated to show the purification performance good and the reconstruction successful.
An upgraded cryogenic test stand for HL-LHC cryo-assemblies
Authors: Rabehl R , Al Atassi O , Chlachidze G , Feher S , Koshelev S , Ranpariya S 
Published: June 2022

Abstract
The Fermilab horizontal test stand previously used for testing the LHC inner triplet quadrupoles has been upgraded to test cryo-assemblies for the high-luminosity LHC upgrade (HL-LHC). The test requirements of these new cryo-assemblies required additional capabilities of the test stand cryogenic system, including controlled cool-down and warm-up, helium recovery after a quench, and operation at higher pressures. Most of these upgrades were completed to support a zero-magnet test in late 2020, with the remainder of the upgrades completed to support the first pre-series cryo-assembly test in early 2022. An overview of the design and initial operating experience of the upgraded test stand cryogenic system and associated process controls system are presented in this paper.
Design of the cryostat for High Field Vertical Magnet Testing Facility at Fermilab
Authors: Koshelev S , Tope T , Theilacker J , Nikolic V , Velev G , Voirin E , Marone A J , Kovach P E 
Published: June 2022

Abstract
High Field Vertical Magnet Test Facility (HFVMTF) is a joint project between the Office of High Energy Physics (HEP) and the Office of Fusion Energy Sciences (FES). Its construction is currently under way at Fermi National Accelerator Laboratory (Fermilab). As a part of the project a new double bath superfluid helium cryostat has been designed. The cryostat can accommodate magnets with up to 20 tonne weight and 1.3 m diameter. This paper discusses challenges and solutions for cryostat, lambda plate and heat exchanger design, and presents results of performance analysis.
Thermohydraulic simulation of quenches and quench recovery for the HL-LHC IT String test bench at CERN
Authors: Rolando G , Wanninger A , Perin A 
Published: June 2022

Abstract
In the framework of the High Luminosity LHC (HL-LHC) project, a new test system - the Inner Triplet (IT) magnets String - for the characterization and validation of the collective behaviour of a 60 m long string of magnets is being built in the SM18 cryogenic test facility at CERN. Among the main objectives of the IT String is the assessment of the magnet performance during the resistive transition from the superconducting to the normal state (quench) when energies up to 39.1 MJ are released into the magnet cold mass and into the helium. In this paper we present the thermohydraulic study performed to design the quench recovery system of the IT String, which limits the pressure rise in the magnets during a quench and ensures the recovery of the operating conditions within the required timeframe. As a new design method, a 1-D thermohydraulic model of the quench relief system has been created using the EcosimPro software with the CRYOLIB library developed at CERN.
A comparative study of two liquid air energy storage systems with LNG cold energy recovery
Authors: Ji W , Hu J , Guo L , Gao Z , Fan X , Chen L , Wang J 
Published: June 2022

Abstract
Due to the nature of fluctuation and intermittency, the increasing penetration of wind and solar power will bring a huge impact to the power grid management. Therefore the concept of liquid air energy storage system was proposed. Compared to compressed air energy storage, liquid air energy storage has a larger storage capacity and no geographic constraints owing to the high density of liquid air. In order to obtain the optimum system design, two different liquid air energy storage systems with LNG cold energy recovery were studied. For one system, the LNG cold energy was used to precool the compressor inlet air to decrease the compression work. For another one, the LNG cold energy was applied to supplement the cold energy needed to liquefy the air and realize the decoupling between the energy storage and release processes. Thermodynamic analysis based on steady-state mathematical model was employed to evaluate the system performance difference.
Study on the selection method of solid cold energy storage medium for liquid air energy storage
Authors: Guo Luna , Ji Wei , Gao Zhaozhao , Fan Xiaoyu , Hu Jianying , Chen Liubiao , Wang Junjie 
Published: June 2022

Abstract
Liquid air energy storage (LAES) is a promising large-scale energy storage technology. A packed bed cryogenic regenerator was investigated for cold energy storage in the LAES system. As the thermophysical properties of the filling material directly affects the performance of the regenerator, sensitivity analyses of the specific heat capacity and thermal conductivity were carried out. Results show that the thickness of the thermocline in the packed bed can be reduced by increasing the specific heat capacity and decreasing the thermal conductivity. Furthermore, the synergy effect of the specific heat capacity and thermal conductivity on the system was considered. In the case of simultaneous changes of the two parameters, the selection method of the solid material was proposed innovatively, and the feasibility of the method was verified by theoretical calculation of various materials.
Thermodynamic analysis of the non-ideal cryogenic packed bed regenerator for the liquid air energy storage system
Authors: Guo L , Ji W , Gao Z , Fan X , Hu J , Chen L , Wang J 
Published: June 2022

Abstract
Liquid air energy storage (LAES) is one of the most recent technologies introduced for grid-scale energy storage. The cryogenic regenerator, which can greatly affect the system efficiency, is the key component of the system. A non-ideal packed bed regenerator for the LAES system was investigated. The cold energy loss and the axial heat conduction of the packed bed regenerator exist in the intermittent period between the charging and discharging process, which significantly degrades the system performance. With rock particles used as the cold energy storage medium, the axial temperature distributions of the packed bed regenerator with different initial temperatures and intermittent periods were compared. Also, the cold energy loss with different boundary conditions was analysed. The results show that the intermittent period exacerbates the negative impact of the axial heat conduction on the performance of the packed bed, and the thickness of the thermocline decreases as the inlet temperature of the cold end decreases. Moreover, as the cold energy loss increases, the cold energy storage efficiency of the packed bed decreases significantly.
Technical and economic evaluation of a liquid air energy storage system with air precooling for compressor inlet
Authors: Gao Z , Hu J , Ji W , Guo L , Fan X , Guo J , Chen L , Wang J 
Published: June 2022

Abstract
The intensification of carbon emissions and the energy crisis have made the safe and reliable application of renewable energy in the energy supply system significantly urgent. Liquid air energy storage (LAES) system is an effective means to solve the time and space mismatch between energy supply and demand. The LAES has the advantages of no geographical restrictions, high energy storage density and flexible operation, making it available to integrate with other industrial processes. In traditional LAES, the heat generated in the compression process is used to supplement the heat in the expansion process, and the excess heat is dissipated. In this study, the compressor inlet air is cooled by absorption refrigeration cycle to avoid excess compression heat, which reduces the power consumption of the compressor and improves the efficiency of the system. The sensitivity analysis of the ambient temperature and the compressor stages on the system efficiency is performed. Furthermore, a comparative analysis between the absorption refrigeration cycle driven by the waste heat and the compression refrigeration cycle driven by electricity for air precooling of the compressor inlet was carried out, and the system round-trip efficiency, exergy efficiency and initial investment cost was selected as indicators for system evaluation.