• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.7
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• pp.813-819
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• 2011

In this research, we investigated the hydrogen-gas filling characteristics of ultra-light composite tanks that have a plastic or aluminum liner inside the composite shell. The study was performed for different gas and tank temperatures. The temperature changes at various positions in the Type-4 tank during hydrogen-gas filling were monitored in order to understand the effects of the filling conditions. The results were compared with those obtained for a Type-3 tank. As the filling speed was increased, a quicker temperature rise was observed, and the temperature distribution over the entire region showed significant discrepancies.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.4
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• pp.345-350
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• 2020

Hydrogen is an green energy without pollution. Recently, fuel cell electric vehicle has been commercialized, and many studies have been conducted on hydrogen tanks for vehicles. The hydrogen tank for vehicles can be charged up to 70 MPa pressure. In this study, the change in filling time, pressure, and temperature for each hydrogen level in a 59 L hydrogen tank was predicted by numerical analysis. The injected hydrogen has the properties of real gas, the temperature is -40℃, and the mass flow rate is injected into the tank at 35 g/s. The initial tank internal temperature is 25℃. Realizable k-epsilon turbulence model was used for numerical analysis. As a result of numerical analysis, it was predicted that the temperature, charging time, and the mass of injected hydrogen increased as the residual capacity of hydrogen is smaller.

• Journal of computational fluids engineering
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• v.20 no.1
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• pp.16-25
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• 2015

The present study investigates the sloshing phenomena in a two-dimensional rectangular tank at a low filling level by using a level set method based on finite volume method. The code validations are performed by comparing between the present results and previous numerical and experimental results, which gives a good agreement. Various excitation frequencies and excitation amplitude of the 30% filling height tank have been considered in order to observe the dependence of the sloshing behavior on the excitation frequency and amplitude. Regardless of excitation amplitude, the maximum value of wall pressure occurs when the excitation frequency reaches the natural frequency. The time sequence of free surface and corresponding streamlines for excitation frequencies have been presented to analysis the variation of wall pressure according to time, which contributes to explain the double peaks in the time variation of wall pressure.

• Tunnel and Underground Space
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• v.22 no.6
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• pp.403-411
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• 2012

In recent, the using of the hydraulic filling method has increased on the underground reinforcement of the abandoned mine in Korea, however it is the lack of research on the efficient filling method. In this study, tank model tests and field tests were conducted for development of tip device for filling efficiency improvements on the hydraulic filling method. In tank model experiments, the filling efficiency was evaluated according to the form and angle of the nozzle on tip device in the same condition. Then tip device model designed by tank model tests was applied to the field experiment. As a result, the amount of filling of nozzle $90^{\circ}$ tube is increased by approximately 18% compared to the common vertical injection pipe. The angle of repose was $30.82^{\circ}$. Filling hole spacing in the field is usually designed from 5m up to 10m assumed to be $40^{\circ}$ of the angle of repose. According to the results of this study, it is possible that the filling hole spacing expands at least 10m up to 15m applied to be $30^{\circ}{\sim}35^{\circ}$ of the angle of repose. Therefore, it is expected to be economical and efficient mine filling.

• Journal of Aerospace System Engineering
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• v.18 no.3
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• pp.8-16
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• 2024

Because hydrogen has very low density, a different storage method is required to store the same amount of energy as fossil fuel. One way to increase the density of hydrogen is through liquefaction. However, since the liquefied temperature of hydrogen is extremely low at -252 ℃, it is easily vaporized by external heat input. When liquid hydrogen is vaporized, a self-pressurizing phenomenon occurs in which the pressure inside the hydrogen tank increases, so when designing the tank, this rising pressure must be carefully predicted. Therefore, in this paper, the internal pressure of a cryogenic liquid fuel tank was predicted according to the liquid hydrogen filling ratio. A one-dimensional thermodynamic model was applied to predict the pressure rise inside the tank. The thermodynamic model considered heat transfer, vaporization of liquid hydrogen, and fuel discharging. Finally, it was confirmed that there was a significant difference in pressure behavior and maximum rise pressure depending on the filling ratio of liquid hydrogen in the fuel tank.

• Progress in Superconductivity and Cryogenics
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• v.16 no.4
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• pp.71-77
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• 2014

For a long-term space mission, filling process of cryogenic liquid propellant is operated on a space vehicle in space. A vent process during transfer and filling of cryogenic propellant is needed to maintain the fuel tank pressure at a safe level due to its volatile characteristic. It is possible that both liquid and vapor phases of the cryogenic propellant are released simultaneously to outer space when the vent process occurs under low gravity environment. As a result, the existing filling process with venting not only accompanies wasting liquid propellant, but also consumes extra fuel to compensate for the unexpected momentum originated from the vent process. No-Vent Fill (NVF) method, a filling procedure without a venting process of cryogenic liquid propellant, is an attractive technology to perform a long-term space mission. In this paper, the preliminary experimental results of the NVF process are described. The experimental set-up consists of a 9-liter cryogenic liquid receiver tank and a supply tank. Liquid nitrogen ($LN_2$) is used to simulate the behavior of cryogenic propellant. The whole situation in the receiver tank during NVF is monitored. The major experimental parameter in the experiment is the mass flow rate of the liquid nitrogen. The experimental results demonstrate that as the mass flow rate is increased, NVF process is conducted successfully. The quality and the inlet temperature of the injected $LN_2$ are affected by the mass flow rate. These parameters determine success of NVF.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.34-37
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• 2007

Propellant filling and holding test was carried out using liquid oxygen as a working fluid. The feeding line system has a filter at propellant tank outlet. Vaporization of liquid oxygen during holding after completion of filling and effect of vaporization to recirculation performance in this system was observed. Filling rate and pressure of tank ullage had the effect on state of liquid oxygen in feeding line. There was no geysering in feeding line during holding because of the position of filter.

• Journal of the Korean Society of Safety
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• v.33 no.6
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• pp.50-57
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• 2018

The purpose of this study is to evaluate the practical application of the self consolidating concrete for the steel concrete pannel (SCP) in module LNG storage tank proposed in the previous research. We evaluated the physical properties and filling performance of developed concrete for the SCP module. First, a slump flow test was conducted to evaluate the performance of the proposed guidelines for the filling test. As a result, all of the concrete used showed satisfactory performance. Based on the results of the previous study, it was found that the reliability of the required time measured by the $T_{500}$ test and the rheometer results measured before and after pumping was 0.94 which means the separation and blocking should not occur. The L-box test and the U-box test were conducted before and after pumping. All of the guidelines suggested showed satisfactory performance. SCP module for LNG storage tanks was fabricated on actual size scale to evaluate the practical application at the final site. As a result, it was confirmed that satisfactory filling performance was obtained in all the specimens.

• Journal of Ocean Engineering and Technology
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• v.32 no.6
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• pp.440-446
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• 2018

The effects of an anti-rolling tank (ART) on vessel motions were numerically investigated. The potential-based BEM vessel motion simulation program and particle-based computational fluid dynamics program were dynamically coupled and used to perform a simulation of vessel motions with ART. From the time domain simulation results, the response amplitude operators for sway and roll motions were obtained and compared with the corresponding experimental and numerical results. Because the main purpose of ART was only to reduce roll motions, it was important to show that the natural properties of a floating vessel were not changed by the effects of ART. Various ART filling ratios and several ART positions were considered. In conclusion, ART only reduced the roll motion regardless of its filling ratio and position.

• Journal of the Korean Institute of Gas
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• v.15 no.5
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• pp.37-41
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• 2011

This paper presents the strength safety of a hydrogen gas composite fuel tank, which is analyzed using a FEM based on the criterion of US DOT-CFFC and Korean Standard. A hydrogen gas composite tank in which is fabricated by an aluminum liner of 6061-T6 material and carbon fiber wound composite layers of T800-24K is charged with a filling pressure of 70MPa and a gas storage capacity of 130 liter. The FEM results indicated that von Mises stress, 255.2MPa of an aluminum liner inner tank is low compared with that of 95% yield strength, 272MPa. And a carbon fiber stress ratio of a composite fuel tank is 3.11 in hoop direction and 3.04 in helical direction. These data indicate that a carbon fiber gas tank is safe in comparison to that of a recommended criterion of 2.4 stress ratio. Thus, the proposed composite tank with 130 liter capacity and 70MPa filling pressure is usable in strength safety.