Cryogenic Containers Research Articles

Modeling temporal dynamics of a radiant Casson fluid near a steeped plate emitting heat and mass fluxes

AbstractIn today's rapidly advancing world, more deliberate development and implementation of energy‐efficient thermal management systems is emergent. In industrial and engineering contexts, the regulation of heat and mass transfer phenomena is heavily swayed by factors such as heat and mass fluxes, and wall temperature, and concentration levels. In cryogenic containers, understanding heat flux and wall temperature is essential for maintaining ultra‐low temperatures over extended periods. In this context, our paper embarks on modeling the transient dynamics of a radiant Casson fluid adjacent to a steeped plate, which is featured by its emission of both heat and mass fluxes. The plate is under two thermal conditions, namely uniform wall temperature (UWT) and uniform heat flux (UHF), which are crucial in modulating both upward and downward heat transport processes. The Laplace transform (LT) technique yields close‐form solutions for the model's governing equations. The distribution of flow and salient physical quantities are graphed and elucidated in response to intricate physical parameters. A comparative graphical analysis of UWT and UHF scenarios reveals stark differences. Notably, the fluid's flow rate appears considerably amplified in the UWT scenario compared to the UHF one. Furthermore, the UHF setting profoundly influences the heat and mass transportation within the fluid's flow realm. A pronounced Casson parameter tends to thin out the velocity profile. Concurrently, a heightened radiation parameter results in a reduction in fluid temperature. The theoretical framework explored in our study is not just an academic exercise but holds tangible applicability across varied sectors. This spans from rocket chamber cooling, where fine‐tuned heat flux conditions are paramount for safeguarding operations, to industries like cosmetics and food processing, which demand meticulous thermal regulation to ensure product excellence.

Frost layer growth behavior study on a cryogenic surface with water vapor content

Frosting under cryogenic conditions is common in liquefied natural gas (LNG), cryogenic containers, cryogenic wind tunnels, cryopump and other engineering fields, but the corresponding researches are still insufficient compared with that under general-low temperature conditions. Especially, research on extra-low-content water vapor frosting under cryogenic conditions stays almost blank. A visualization experiment system was built, based on which cryogenic frosting experiments of water-vapor-carrying nitrogen gas flow with different water vapor contents (120 ppmv ≤ ωin ≤ 780 ppmv) considering the cooling process (from 290 K to 100 K) were carried out. Images through the whole frosting period were recorded and image processing was executed. The evolution of the frost surface was captured and the translation velocity was calculated. Physical properties of the frost layer including thickness (as large as 1.75 mm at 2 h) and roughness (up to 76.2 μm) were obtained and compared with humid air frosting. The frost layer growth pattern transition from needle-like vertical growth to clump-grass-like circular rotational growth was observed in the rapid cooling stage. The results reveal differences in frost formation mechanisms and characteristics from general-low to cryogenic temperatures and can provide a quantitative reference for mass and heat transfer analysis in practical frosting circumstances.

EXPERIMENTAL STUDY ON THE FACTORS AFFECTING THE INSULATION PERFORMANCE OF FLAME-RETARDANT MULTILAYER INSULATION MATERIALS

Flame-retardant multilayer insulation materials act as effective thermal insulation blankets of cryogenic containers that store flammable and explosive cryogenic liquids. This study used standard static liquid nitrogen boil-off calorimetry to test the insulation performance of eight groups of flame-retardant multilayer insulation materials with different wrapping parameters. The effects of four factors, namely the layer density, seaming process, number of reflector layer, and variable-density multilayer insulation arrangement, on the insulation performance were analysed. Three layer densities were considered: 4.47, 3.08, and 2.50 layers/mm. Two types of seaming processes were discussed: the overlapped and fold-over seaming processes. Three numbers of reflector layers were considered: 60, 70, and 80. Two variable-density multilayer insulation arrangements with similar thicknesses were discussed: 10-10-40 and 20-20-20 layers of reflectors allocated for low-, medium- and high-density segments. The conclusions are as follows: Decreasing the layer density enhances the performance of multilayer insulation; Using the fold-over seaming process results in less heat flux and lower apparent thermal conductivity; An increase in the number of reflector layers weakens radiative heat transfer, resulting in better thermal insulation; Furthermore, for a given wrapping thickness, reducing the number of reflectors appropriately in low- and medium-density segments improves the insulation performance; Optimizing and controlling the layer density of each density segment are also essential for variable-density multilayer insulation effects. This study provides supporting theories and reference data for practical engineering applications.

Experimental study on composite insulation with foam, multilayer and vapor cooled shield for cryogen storage under different vacuum conditions

The composite insulation composed of polyurethane foam (Foam), vapor cooled shield (VCS) and multi-layer material (MLI) can effectively reduce the heat leakage into the ground cryogenic vessels and space-used cryogenic containers throughout their whole life cycle. To comparatively evaluate the thermal performance of the MLI-VCS and the Foam-MLI-VCS combinations, an experimental setup has been designed and fabricated based on the evaporation calorimetry. It allows control of the warm boundary temperature between 150 K and 400 K and the environmental pressure in a wide range of 10−5–105 Pa. With the help of this facility, the thermal performance of the target insulation structures was evaluated at various warm boundary temperatures and different vacuum pressures. The temperature profiles and heat flux in the insulation were obtained. The results indicated that the heat fluxes into the liquid nitrogen vessel decreased by approximately 11.7% and 19.7% after installing a VCS when the warm boundary temperatures were 223.3 K and 332.4 K, respectively. Besides, the contribution to the overall performance by the VCS gradually decreases with the deterioration of the vacuum pressure. Under high vacuum (9.8 × 10−5 Pa) conditions, VCS reduces the heat leakage into a liquid nitrogen container by 19.7% while it drops to merely 0.3% under atmospheric pressure (1.0 × 105 Pa). The results will be beneficial to the VCS-related thermal design.

Predicting BOG rate in cryogenic containers at different liquid levels based on a single test

Predicting BOG rate in cryogenic containers at different liquid levels based on a single test

High-Entropy Alloys for Solid Hydrogen Storage: Potentials and Prospects.

Hydrogen storage is one of the most significant research areas for exploiting hydrogen energy economy. To store hydrogen with a high gravimetric/volumetric density, gaseous hydrogen storage systems require a very high-pressure compressed gas cylinder which is quite unsafe and the storage in the liquid form needs cryogenic containers to be maintained at roughly 20 K under ambient pressure because hydrogen has a very low critical temperature of 33 K. However, hydrogen can be stored in solid materials with higher concentration of hydrogen compared to the gaseous and liquid hydrogen storage systems. It is therefore, worthwhile to look into the experimental and theoretical research on prospective hydrogen storage materials. The hydride-forming alloys and intermetallic compounds are found to be the most important families of hydrogen storage materials. Multicomponent alloys consisting of five or more principal elements, also known as high-entropy alloys appear to have potential for the development as hydrogen storage materials. Hydride-forming elements like Ti, Zr, V, Nb, Hf, Ta, La, Ce, Ni, and others have been shown to have hydrogen storage properties and the ability to produce single-phase high-entropy intermetallics. Here, attempts will be made to present a short review on utilization of multicomponent high-entropy alloys as solid hydrogen storage materials. Furthermore, we will also present some of our work on the synthesis, structural–microstructural characterization and hydrogen storage properties of Ti–Zr–V–Cr–Ni equi-atomic hydride-forming high-entropy alloys. From the preliminary investigation, the maximum storage capacity in this system was observed to be 1.78 wt%, which is comparable to other hydrogen storage materials. The prospects of high-entropy-based alloys for hydrogen storage will be discussed.

Equivalence of the Moral Objects in Embryo Adoption and Heterologous IVF

Embryo adoption is a topic of considerable debate in the Church. Well over a million human embryos are currently being kept in cryogenic containers with little prospect of survival. The desire to rescue these vulnerable human beings is natural. However, the processes required to do so raise serious questions regarding the ethics of embryo adoptions. The violation of the unitive and procreative aspects of human intercourse and its ramifications on the moral status of heterologous embryo transfer are key to understanding the reasoning behind some objections to human embryo adoption.

Major Russian helium project comes on line

The era of vexing helium shortages is likely at an end. The Russian state-owned company Gazprom brought 20 million m 3 of new helium capacity on line earlier this month when it opened the first of three helium production lines at its Amur gas-processing plant in southeastern Russia. The firm also commissioned a related logistics center that will feed liquid helium into cryogenic containers for shipment around the world. Helium will also flow from Amur via pipeline to nearby buyers in China. The facility boosts the global supply of helium by about 11%, according to helium consultant Phil Kornbluth. When all three lines are up and running, Amur is expected to provide 60 million m 3 of helium per year alongside methane, ethane, and other less valuable products. Gazprom says Amur will reach full capacity in 2025. The opening of the first Amur plant should mark the end of more

A numerical model for liquid–vapor transition in self-pressurized cryogenic containers

The boil-off loss and self-pressurization have always been great concerns in the cryogen storage systems. Accurate prediction of the self-pressurization process in a cryogenic storage tank exposed to extremely low heat flux usually requires tremendous computational resources. General commercial computational fluid dynamic software is incompetent for pressure estimations lasting days or even months with regular hardware support. This paper proposed an optimized computational model for transient simulation of the self-pressurization process in cryogenic storage tanks based on the open source platform OpenFOAM. Ten times improvement in the calculation speed was achieved compared to the widely used commercial solvers, without compromising the accuracy. An optimal region was found and suggested for the evaporation and condensation coefficients. The commonly used “constant heat flux boundary” has been proved overestimating thermal stratification in the axial direction parallel to the tank wall. The model enables quick and accurate simulation for the long-term self-pressurization in cryogenic storage tanks applied in the industry for liquid hydrogen, liquefied natural gas, and liquid air products storage and deep space exploration programs. • 10 times improvement in the simulation speed is achieved. • The model’s precision is higher than the thermodynamic equilibrium models. • Effect of model coefficients on the self-pressurization evolution is revealed.

Ecological Fueling System for Vehicles Equipped With Combustion Engines

The expected global energy crisis as well as major environmental issues, amid global warming, have led to the imperative need to limit the Carbon Dioxide emissions as well as overall fossil fuel consumption. The production of fossil fuels is itself in crisis, being increasingly unclear the real value of the hydrocarbon reserves available to the planet. All the more so as the growing human society in the coming decades will have almost an exponential growth of the consumption of energy resources of any kind. As the nuclear industry has been in a standstill for a long time and the exploitation of fossil energy resources has an increasingly limited future, it is necessary to discover and develop new fuels obtained on other technological bases than classical ones. As is already known, the optimal fuel (from all points of view, including from an ecological perspective) is the Hydrogen. Unfortunately, although relatively easy to obtain through various industrial methods, the Hydrogen is very difficult to store, requiring tanks under high pressure or cryogenic containers. In this context, an easy Hydrogen production by a provoked and artificially maintained photosynthesis could be a technologically advanced solution in the next few decades.

Numerical Study of the Filling Process of a Liquid Hydrogen Storage Tank under Different Sloshing Conditions

Cryogenic vessels are widely used in many areas, such as liquefied natural gas (LNG), aerospace, and medical fields. A suitable filling method is one of the prerequisites for the effective use of cryogenic containers. In this study, the filling process for the sloshing condition of a liquid hydrogen storage tank is numerically simulated and analyzed by coupling the sloshing model and the phase-change model. The effects of different sloshing conditions during the filling process are investigated by changing the amplitude and frequency of the sloshing. Within the scope of this study, there is a critical value for the effect of sloshing conditions on the pressure curve during the filling process. The critical value corresponds to a frequency f equal to 3 Hz and an amplitude A equal to 0.03 m. According to the simulation results, when the sloshing exceeds the critical value, the internal pressure curve of the storage tank increases significantly. Under microgravity conditions, within the scope of this study, the pressure curve changes less than the normal gravity, even if the amplitude and frequency increase. The sloshing makes it easier for the liquid to spread along the wall during the filling process. This also further weakens the temperature stratification in the storage tank.

Development and manufacturing of large cryogenic containers for storage and transportation

This paper covers the development and manufacture of large vacuum insulated cryogenic containers for storage and transportation in the context of technology developments over the years, and large scale use of industrial cryogenics. Apart from covering design and manufacture of vacuum insulated containers, paper also describes the latest trends and applications associated with Liquefied Natural Gas (LNG).

Cryogenic impact resistance of chopped fiber reinforced polyurethane foam

Liquefied natural gas (LNG) is primarily carried by a membrane type LNG ship, which has a cryogenic containment system composed of dual tightness barriers and insulation boards. The insulation board should have cryogenic reliability as well as high thermal insulation for the safe and efficient transportation. Sandwich construction and fiber reinforced polyurethane foam (PUF) are generally used for the insulation board and the core materials, respectively. During the operation of the LNG ship, cavitation and sloshing could generate an impact load on the PUF, which is an ongoing concern in the ship building industry.Therefore, the cryogenic impact resistance of the chopped E-glass fiber reinforced PUF was investigated with respect to the amount of chopped fibers. The drop weight impact test was conducted at a cryogenic temperature of −196°C using liquid nitrogen. The applied maximum impact pressure, permanent strain and damage factor were measured to assess the damage caused by the impact test, from which the critical impact energy was investigated. From the experimental results, a criterion was suggested to assess the cryogenic impact resistance of the PUF and it was determined that the chopped fiber reinforcement significantly increased the impact resistance of the PUF at the cryogenic temperature.

Cryogenic strength of adhesive bridge joints for thermal insulation sandwich constructions

Cryogenic containment systems for LH2 (Liquid Hydrogen) and LNG (Liquefied Natural Gas) generally require two barriers: the primary barrier made of stainless steel or Invar which contacts directly the cryogenic liquids, the secondary barrier made of composite or metal foil which functions as the faces of sandwich constructions for thermal insulation.The faces of sandwich constructions are bridged with metal strips which are usually adhesively bonded for gas tightness. When cryogenic liquids are loaded in the containment system, the adhesive bridge joints are subjected to both the thermal load and deformation due to the shrinkage of the sandwich constructions.Since the maximum deformation in the sandwich construction systems may occur in the metal bridge between the two sandwich constructions, the cryogenic performances of adhesive bridge joint with level difference, which would be generated due to manufacturing tolerance, were evaluated using both the new appropriate test method and FE analysis.

Fracture toughness improvement of polyurethane adhesive joints with chopped glass fibers at cryogenic temperatures

Polyurethane (PU) adhesive is widely used for bonding the secondary barrier of cryogenic containment systems (CCS) of liquefied natural gas (LNG) ships due to its ductility at room temperature, although it can become brittle at the cryogenic temperature below its glass transition temperature.To evaluate the reliability of PU adhesive at the cryogenic temperature of −150°C, the fracture toughness of double-cantilever-beam (DCB) adhesive joints composed of stainless steel and aluminum adherends was measured. Because the fracture toughness of the PU adhesive was found to be very low at the cryogenic temperature, the adhesive was reinforced with chopped glass fibers. The fracture toughness with respect to the length and volume fraction of the chopped glass fibers was then measured. Based on the experimental results, an optimal reinforcement method is suggested for the reliable application of PU adhesive at cryogenic temperatures.

Cryogenic characteristics of chopped glass fiber reinforced polyurethane foam

Liquefied natural gas (LNG) is mainly carried by membrane type LNG ships, whose cargo containment system is composed of dual tightness barriers and two insulation boards. The insulation board should have not only cryogenic reliability against thermal load, but also high thermal insulation performance for safe and efficient transportation of LNG. Although polyurethane foam (PUF) has been widely used for the insulation board due to its low production cost and relatively good thermal and mechanical properties, the cryogenic reliability of PUF is a remaining concern in marine fields due to its brittleness at cryogenic temperatures.In this work, the PUF was reinforced with chopped E-glass fiber because of its good dispersion and distribution characteristics. The compression, tension and the fracture toughness test were conducted with respect to the amount of the chopped E-glass fiber both at the room (25°C) and cryogenic (−150°C) temperatures. From the experimental results, it was found that the chopped E-glass fiber reinforcement increased the fracture toughness of the PUF much, especially at the cryogenic temperature. Therefore, the PUF reinforced with chopped glass fibers will improve much the reliability of the LNG cryogenic containment system during the voyage of LNG ships.

Dynamic properties of the corrugated stainless steel membrane reinforced with the glass composite pressure resisting structure for LNG carriers

The primary barrier of cryogenic containment system (CCS) of liquefied natural gas (LNG) carriers is composed of corrugated stainless steel to reduce the thermal stress at the LNG temperature of −163°C under the pressure of 0.11MPa. The corrugation of the primary barrier not only buckles easily by the cavitation impact of LNG, but also produces large tumbling noise, which irritates the crews of LNG carriers.In this work, the corrugation of primary barrier was reinforced with the pressure resisting structure (PRS) of E-glass fiber epoxy composite to increase both the buckling resisting capability of the corrugation and to decrease the tumbling noise and vibration due to the cavitation impact of LNG. The natural frequency and damping ratio of the corrugation with and without PRS were measured, and various damping materials were wrapped around the PRS to determine an optimum vibration suppression structure. Also the impact load transmissibility of the primary barrier with PRS was investigated by the drop weight impact test, from which an optimum combination of PRS and the damping material has been suggested.

Cryogenic Performance of Adhesively Bonded Joints Composed of Thin Metal Adherends

Thin metals for cryogenic containment systems (CCS) are generally joined using adhesives due to the benefit of stress distribution over larger area and sealing effect. This article reviews the existing literature related to the adhesively bonded joints composed of thin metal adherends at the cryogenic temperature. At the cryogenic temperature, polymeric adhesives become very brittle although they are ductile at the room temperature, while the properties of metals for the cryogenic purpose, such as austenitic stainless steel or aluminum, change only little because they have face cubic lattice structure or hexagonal close-packed lattice structure without nil ductility temperature which is the temperature of material behavior from ductile to brittle. Previous researches on the adhesive joints at cryogenic temperatures have focused on improving the adhesion characteristics of adhesives through surface treatments of metal adherends and the reinforcement of adhesives to improve their fracture toughness. The surface treatments such as chemical, energetic and mechanical treatments, and the reinforcement of adhesives with fibers such as polyester, glass fiber and aramid fibers are indispensable for the reliability of the adhesive joints at cryogenic temperatures. Also, ageing effects after the surface treatment of metal adherends was clarified to apply the adhesively bonded metal joints to the actual CCS.

Improvement of the adhesive peel strength of the secondary barrier with level difference for LNG containment system

Cryogenic Containment Systems for LNG (Liquefied Natural Gas) ships are required to satisfy durability and safety for 40years of operation. Membrane type LNG containment ships generally consist of three parts such as the primary barrier which is made of stainless steel, the secondary barrier which is made of composite or metal foil, and the insulation board which is made of polymer foam. The secondary barriers which are the face parts of sandwich insulation boards are adhesively bonded with metal strips to keep the gas tightness. When LNG is loaded in the containment system, large thermal stresses are generated in the metal strips due to the cryogenic temperature of LNG (−163°C). If there is a level difference between the insulation boards, the adhesively bonded metal strips are subjected to peel stress due to the level difference.In this work, FEM analysis was performed to calculate the critical peel load with the level difference of 3mm between the insulation boards due to the non-uniform flatness of the inner hull structure of LNG ships. To verify the adhesive strength, a new peel test method representing height differences of the secondary barrier was developed. Finally, the adhesive was reinforced with E-glass fiber to increase the peel strength of adhesive and the optimal areal mass of E-glass fiber reinforcement was determined by the new peel test method.

Vibration isolation of LNG containment systems due to sloshing with glass fiber composite

Since the stainless steel primary barriers of Cryogenic Containment System (CCS) for Liquefied Natural Gas (LNG) ship failed by impact loads due to LNG cavitation during operation, the stiffness and strength of the primary barrier was increased much to endure the impact pressure of LNG, which increased the transfer of impact load to foam insulation panels under the primary barrier. The increase of impact load to the foam insulation panels will induce crack propagation into the insulation foam panels due to the low toughness of insulation foams at cryogenic temperatures. In this work, an impact isolation system was developed using glass fiber composite mats to lower the impact load transmission into the foam insulation panels. An optimal design process for the vibration isolation system was conducted by a numerical method. For reliability of the impact isolation system, cryogenic fatigue tests of the glass fiber composite mats were performed. Also, an impact test equipment with low impact duration was developed to simulate the efficiency of the impact isolation system.