Search Results (101)

The structural health monitoring (SHM) of microcracking in cryogenic hydrogen storage tanks is a critical aspect for ensuring long-term safety and operational reliability. Early detection of such damage can prevent leaks and structural failure, making the development of sensitive, non-intrusive diagnostic techniques essential. In this study, a series of experimental tests were conducted to evaluate the feasibility of using thermal expansion behavior as a potential SHM indicator. The material under investigation was a carbon–epoxy composite laminate (M21/IMA) with a [0/90]_2s layup, representative of those used in cryogenic aerospace applications. Artificial microcracks were introduced at cryogenic temperatures (approximately 20 K), followed by thermal expansion and gas permeability measurements. The objective was to explore the correlation between induced damage and measurable physical changes, with the aim of assessing the viability of this approach for future SHM strategies in liquid hydrogen tank systems. Full article

Cryogenic technologies are a crucial field of modern engineering, with applications in liquefied gas transport, renewable energy, aerospace, and high-precision medicine. Their advancement relies heavily on the performance and reliability of cryogenic tanks, which ensure the safe storage and handling of fluids at extremely low temperatures. This paper presents a concise review of recent engineering innovations, focusing on fluid behavior in single- and two-phase regimes, boil-off mechanisms, advanced thermal insulation, and energy loss control strategies. Recent numerical and experimental studies indicate that optimized insulation configurations, such as the placement of a low-emissivity intermediate layer near the cold wall, can reduce radiative heat loads by approximately 40–60%, thereby significantly mitigating cryogenic liquid boil-off. Developments in structural materials, functional coatings, and numerical simulations are also discussed, as they contribute to enhancing tank efficiency under demanding operational conditions. Particular emphasis is placed on material selection and surface engineering solutions aimed at reducing corrosion, improving cryogenic resistance, and extending service life. These approaches not only lower maintenance costs but also strengthen safety and sustainability in cryogenic applications. In addition, current industry trends are highlighted, including equipment miniaturization, integration into mobile platforms, and the adoption of international standards for safety and efficiency. The paper aims to provide an interdisciplinary synthesis that supports both academic research and the development of durable, high-performance cryogenic systems. Full article

Concrete is prone to deterioration and increased permeability under cryogenic freeze–thaw cycles. In this study, a novel method was proposed to prepare a nano-silica-modified epoxy resin composite coating with excellent anti-permeability. The effects of layer composition, a resin layer modified with different nanoparticles, and different nano-silica dosages on the oil impermeability of coated concrete were studied. The mechanical properties and chemical stability of the composite coating were also evaluated. The results showed that the composite coating composed of a nano-silica-modified resin layer, bonding layer, and surface layer presented good resistance to oil penetration under cryogenic freezing cycles. Moreover, nano-silica seemed to be a better choice for resin modification than nano-TiO₂ and graphene. Macroscopic and morphological observation also confirmed a reduction in cracks and the integrity of the composite coating for concrete protection. Therefore, the coated concrete presented good mechanical properties and chemical stability. This study provides a guide for the preparation of composite coating concrete used for mountainous highway bridges and liquefied natural gas tanks. Full article

As the largest cryogenic superconducting platform in China and even Asia, the Shanghai High-intensity Ultrafast X-ray Facility (SHINE) highly depends on the stable operation of 1.3 GHz superconducting accelerating modules in a 2 K superfluid helium environment. This paper elaborates on the key control technologies developed and successfully applied to ensure the smooth aging process of superconducting modules in the cryogenic experiments of the SHINE injector section. To address the issue of thermal load fluctuations caused by the dynamic changes in RF power during the aging process, a dynamic power compensation algorithm based on real-time cavity pressure feedback was proposed and implemented. Meanwhile, a multi-variable coupled PID control strategy was adopted to achieve high-precision stability of the helium tank liquid level (±1%) and cavity pressure (±10 Pa). Experimental results show that this integrated control scheme effectively suppresses the risk of quenching caused by thermal disturbances, significantly improving the aging efficiency and operational reliability of the superconducting modules. This lays a solid technical foundation for the commissioning and long-term stable operation of the superconducting systems of SHINE and similar large-scale scientific facilities. Full article

The use of liquid hydrogen (LH₂) as an energy carrier is gaining traction across sectors such as aerospace, maritime, and large-scale energy storage due to its high gravimetric energy density and low environmental impact. However, the cryogenic nature of LH₂, with storage temperatures near 20 K, poses significant thermodynamic and safety challenges. This review consolidates the current state of modelling approaches used to simulate LH₂ behaviour during storage and transfer operations, with a focus on improving operational efficiency and safety. The review categorizes the literature into two primary domains: (1) thermodynamic behaviour within storage tanks and (2) multi-phase flow dynamics in storage and transfer systems. Within these domains, it covers a variety of phenomena. Particular attention is given to the role of heat ingress in driving self-pressurization and boil-off gas (BoG) formation, which significantly influence storage performance and safety mechanisms. Eighty-one studies published over six decades were analyzed, encompassing a diverse range of modelling approaches. The reviewed literature revealed significant methodological variety, including general analytical models, lumped-parameter models (0D/1D), empirical and semi-empirical models, computational fluid dynamics (CFD) models (2D/3D), machine learning (ML) and artificial neural network (ANN) models, and numerical multidisciplinary simulation models. The review evaluates the validation status of each model and identifies persistent research gaps. By mapping current modelling efforts and their limitations, this review highlights opportunities for enhancing the accuracy and applicability of LH₂ simulations. Improved modelling tools are essential to support the design of inherently safe, reliable, and efficient hydrogen infrastructure in a decarbonized energy landscape. Full article

As global warming accelerates, the Paris Agreement has emphasized the urgent need for technologies that reduce and manage carbon dioxide emissions. Consequently, carbon capture and storage (CCS) has emerged as a critical area of research. For the safe and efficient transportation of captured carbon dioxide in cryogenic tanks, the design must accurately account for the phase change behavior of liquefied carbon dioxide (LCO₂). This study proposes a numerical approach to evaluate the thermal insulation performance of cryogenic tanks by simulating the phase change process of LCO₂. The phase transition of LCO₂ was simulated in a horizontally oriented Type-C cryogenic tank using the open-source computational fluid dynamics (CFD) framework OpenFOAM (v2312). To validate the numerical methodology, the phase change in liquefied nitrogen (LN₂) inside a tank was first simulated and compared with available experimental data. A mesh-independence study was then conducted to determine the optimal grid resolution, and the effects of different equations of state (EOS) for both liquid and gaseous phases, as well as various turbulence models, were examined. The boil-off rate (BOR) and boil-off gas (BOG) generation within the tank were predicted, and variations in internal pressure and flow fields were analyzed. The simulation results over 5000 s showed that the internal tank pressure increased from 7.8 bar to 8.1 bar, and the average temperature rose by approximately 1.3 K. The total mass of LCO₂ decreased from 1439.3 kg to 1431.0 kg. Full article

The hydrogen drive is a promising zero-emission solution in transportation that can be realised through hydrogen internal combustion engines or hydrogen fuel cells. The hydrogen combustion engine’s advantage lies in the simplicity and greater maturity of the technology. At the same time, these solutions require appropriate fuel storage systems. The publication presents an overview of the currently used and developed hydrogen storage technologies. The main focus is placed on hydrogen tanks intended for vehicles powered by hydrogen internal combustion engines. The manuscript describes physical storage, including popular pressurised and cryogenic tanks. Additionally, technologies which can lead to improvements in the future, such as metallic and non-metallic hydrides and sorbents, are presented. The characteristics of the storage technologies in connection with the combustion engines are shown, as well as the outlook for the future of these solutions and their recent uses in vehicles. When focusing on vehicular and combustion applications, their specifics make physical storage methods the leading technology for now. Hydrogen storage today is still not competitive with fossil fuels; however, there are promising developments than can lead to achieving the requirements needed for its viable storage and use. Full article

In response to the International Maritime Organization (IMO)’s greenhouse gas reduction targets and the growing demand for decarbonization in the maritime sector, the development of hydrogen-fueled ship technologies has gained increasing attention. Liquid hydrogen (LH₂) is regarded as a promising marine fuel due to its high energy density per unit volume when liquefied at −253 °C, enabling large-scale storage and transportation. However, critical technical challenges remain in cryogenic storage, transfer, vaporization processes, and safety assurance. This study proposes a conceptual pre-standardization framework for land-based evaluation of LH₂ fuel tank and supply systems, supported by preliminary validation using LN₂ surrogate tests. The protocol is established through a reinterpretation of existing international and domestic standards (KGS AC111, ISO/TR 15916, CGA H-3) and adapted to Korean demonstration environments. Test items were categorized into (i) supply performance (flow and pressure), (ii) vaporization and heating performance (temperature), and (iii) safety functions, with acceptance criteria benchmarked against international guidelines. To overcome the significant safety and cost constraints of handling actual LH₂, liquid nitrogen (LN₂) was applied as a surrogate medium to enable preliminary validation under safe and practical conditions, and process simulations are proposed as a future pathway for comprehensive verification. The results highlight not only the application but also the localization and refinement of global standards into a practical protocol for small- to medium-sized ship applications. This protocol is expected to serve as a critical reference for subsequent sea trials and commercialization, thereby contributing to the advancement of eco-friendly marine fuel technologies and strengthening international competitiveness in the hydrogen powered shipping sector. Full article

In the present study, an Engineering Critical Assessment (ECA) is conducted for an International Maritime Organisation (IMO) Type C liquefied CO₂ (LCO₂) cargo tank to evaluate the effect of finite element configuration on structural integrity in the presence of potential flaws. With the increasing demand for LCO₂ carriers to support carbon capture, utilisation, and storage (CCUS), conventional stress-based design approaches outlined in the International Gas Carrier (IGC) Code have limitations because they neglect imperfections resulting from fabrication and material. To assess these flaws, the fracture mechanics-based ECA methodology, as prescribed by the BS 7910 standard, is applied to a bilobe IMO type C tank designed for cryogenic and pressurised conditions. The assessment integrates fracture toughness, stress intensity factor, and applied loads. Both the two-dimensional shell element model and the three-dimensional solid element model are developed and compared in terms of stress distribution, safety factor for fracture, and fatigue crack growth predictions. Results show that while shell models offer computational efficiency, solid models capture bending stresses and stress concentrations at geometric discontinuities more accurately, resulting in higher reliability in ECA outcomes. The comparative analysis highlights that the web and butt weld near the centre bulkhead are the most vulnerable regions, and fatigue crack growth is highly sensitive to input data, such as stress intensity factor range and fatigue crack growth laws. These findings provide practical guidance for applying ECA in bilobe LCO₂ tank design and safety assessment. Full article

The cooling effect from the para-ortho hydrogen conversion (POC) combined with a vapor-cooled shield (VCS) and multi-layer insulation (MLI) can effectively extend the storage duration of liquid hydrogen in cryogenic tanks. However, there is currently no effective and straightforward empirical correlation available for predicting the catalytic POC efficiency in VCS pipelines. This study focuses on the development of correlations for the catalytic conversion of para-hydrogen to ortho-hydrogen in pipelines, particularly in the context of cryogenic hydrogen storage systems. A model that incorporates the Langmuir adsorption characteristics of catalysts and introduces the concept of conversion efficiency to quantify the catalytic process’s performance is introduced. Experimental data were obtained in the temperature range of 141.9~229.9 K from a cryogenic hydrogen catalytic conversion facility, where the effects of temperature, pressure, and flow rate on the catalytic conversion efficiency were analyzed. Based on a validation against the experimental data, the proposed model offers a reliable method for predicting the cooling effects and optimizing the catalytic conversion process in VCS pipelines, which may contribute to the improvement of liquid hydrogen storage systems, enhancing both the efficiency and duration of storage. Full article

This study proposes an analytical model for the long-term prediction of boil-off gas (BOG) generation in cryogenic storage tanks. The model assumes a saturated liquid and a superheated vapor under open-vent conditions. Heat ingress is estimated using steady-state thermal conduction analysis, and evaporation is then computed from thermodynamic equilibrium. In the first stage, a thermal resistance network quantifies the heat flux transferred to the liquid and vapor regions inside the tank. The network represents external convection, insulation conduction, and internal convection as thermal resistances. In particular, natural convection on the external and internal tank walls, as well as heat transfer at the liquid–vapor interface, are incorporated through appropriate convective heat-transfer correlations. In the second stage, the temporal variations in temperature and phase change of the vapor and liquid are computed. Each phase is modeled as a lumped mass at equilibrium, and the heat ingress obtained from the thermal resistance network is used to simulate the temperature evolution and evaporation process. A numerical model is also developed to capture the time-dependent variations in liquid and vapor heights and the corresponding BOG generation. The proposed model is applied to a 1.0 m³ liquid nitrogen storage tank and validated through comparison with the BoilFAST and SINDA/FLUINT models. The results confirm the validity of the model in terms of heat ingress, vapor temperature evolution, and BOG history. This study provides a practical framework for predicting long-term evaporation phenomena in cryogenic storage tanks and is expected to contribute to the thermal design and performance evaluation of cryogenic storage systems. Full article

As a key zero-carbon energy carrier, the accurate measurement of liquid hydrogen flow in its industrial chain is crucial. However, the ultra-low temperature, ultra-low density and other properties of liquid hydrogen can introduce calibration errors. To enhance the measurement accuracy and reliability of liquid hydrogen flow, this study investigates the heat and mass transfer within a 1 m³ non-vented storage tank during the calibration process of a liquid hydrogen flow standard device that integrates combined dynamic and static gravimetric methods. The vertical tank configuration was selected to minimize the vapor–liquid interface area, thereby suppressing boil-off gas generation and enhancing pressure stability, which is critical for measurement accuracy. Building upon research on cryogenic flow standard devices as well as tank experiments and simulations, this study employs computational fluid dynamics (CFD) with Fluent 2024 software to numerically simulate liquid hydrogen flow within a non-vented tank. The thermophysical properties of hydrogen, crucial for the accuracy of the phase-change simulation, were implemented using high-fidelity real-fluid data from the NIST Standard Reference Database, as the ideal gas law is invalid under the cryogenic conditions studied. Specifically, the Lee model was enhanced via User-Defined Functions (UDFs) to accurately simulate the key phase-change processes, involving coupled flash evaporation and condensation during liquid hydrogen refueling. The simulation results demonstrated good agreement with NASA experimental data. This study systematically examined the effects of key parameters, including inlet flow conditions and inlet liquid temperature, on the flow characteristics of liquid hydrogen entering the tank and the subsequent heat and mass transfer behavior within the tank. The results indicated that an increase in mass flow rate elevates tank pressure and reduces filling time. Conversely, a decrease in the inlet liquid hydrogen temperature significantly intensifies heat and mass transfer during the initial refueling stage. These findings provide important theoretical support for a deeper understanding of the complex physical mechanisms of liquid hydrogen flow calibration in non-vented tanks and for optimizing calibration accuracy. Full article

Hydrogen serves as a key clean-energy carrier, with the main hurdles lying in safe, efficient transport and storage (gas or liquid) and in end-use energy conversion. Liquid hydrogen (LH), as a high-density method of storage and transportation, presents cryogenic insulation as its key technical issues. In LH storage tanks, the performance of high vacuum multilayer insulation (HVMLI) will decline due to hydrogen release and leakage from the microscopic pores of steel, which significantly destroy the vacuum layer. The accumulation of residual gases will accelerate thermal failure, shorten the service life of storage tanks and increase safety risks. Adsorption is the most effective strategy for removing residual gases. This review aims to elucidate materials, methods, and design approaches related to hydrogen storage. First, it summarizes adsorbents used in liquid hydrogen storage tanks, including cryogenic adsorbents, metal oxides, zeolite molecular sieves, and non-volatile compounds. Second, it explores experimental testing methods and applications of hydrogen adsorbents in storage tanks, analyzing key challenges faced in practical applications and corresponding countermeasures. Finally, it proposes research prospects for exploring novel adsorbents and developing integrated systems. Full article

Cryogenic propellant sloshing presents significant challenges in aerospace systems, inducing vehicle instability, structural fatigue, energy losses, and complex thermal management issues. This review synthesizes experimental, analytical, and numerical advances with an emphasis on energy dissipation and conversion efficiency in propellant storage and transfer. Recent developments in computational fluid dynamics (CFD) and AI-driven digital-twin frameworks are critically examined alongside the influences of tank materials, baffle configurations, and operating conditions. Unlike conventional fluids, cryogenic propellants in microgravity and within composite overwrapped pressure vessels (COPVs) exhibit unique thermodynamic and dynamic couplings that remain only partially characterized. Prior reviews have typically treated these factors in isolation; here, they are unified through an integrated perspective linking cryogenic thermo-physics, reduced-gravity hydrodynamics, and fluid–structure interactions. Persistent research limitations are identified in the areas of data availability, model validation, and thermo-mechanical coupling fidelity, underscoring the need for scalable multi-physics approaches. This review’s contribution lies in consolidating these interdisciplinary domains while outlining a roadmap toward experimentally validated, AI-augmented digital-twin architectures for improved energy efficiency, reliability, and propellant stability in next-generation aerospace missions. Full article

In response to the IMO’s decarbonisation strategy, hydrogen—especially green hydrogen—becomes a promising alternative fuel in shipping. This article provides a comparative analysis of two hydrogen propulsion technologies suitable for a service vessel (SOV) operating in offshore wind farms: hydrogen fuel cells and hydrogen-powered internal combustion engines. This study focuses on the use of liquid hydrogen (LH₂) stored in cryogenic tanks and fuel cells as an alternative to the previously considered solution based on compressed hydrogen (CH₂) stored in high-pressure cylinders (700 bar) and internal combustion engines. The research aims to examine the feasibility of a fully hydrogen-powered SOV energy system. The analyses showed that the use of liquefied hydrogen in SOVs leads to the threefold reduction in tank volume (1001 m³ LH₂ vs. 3198 m³ CH₂) and the weight of the storage system (243 t vs. 647 t). Despite this, neither of the technologies provides the expected 2-week autonomy of SOVs. LH₂ storage allows for a maximum of 10 days of operation, which is still an improvement over the CH₂ gas variant (3 days). The main reason for this is that hydrogen tanks can only be located on the open deck. Although hydrogen fuel cells take up on average 13.7% more space than internal combustion engines, they are lower (by an average of 24.3%) and weigh less (by an average of 50.6%), and their modular design facilitates optimal arrangement in the engine room. In addition, the elimination of the exhaust system and lubrication simplifies the engine room layout, reducing its weight and space requirements. Most importantly, however, the use of fuel cells eliminates exhaust gas emissions into the atmosphere. Full article