• Transactions of the Korean hydrogen and new energy society
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• v.34 no.3
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• pp.292-296
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• 2023

Until recently, ships, automobiles, and drones using hydrogen energy are being actively researched. In addition, stations and facilities for hydrogen supply are being developed widely. Among them, a hydrogen pump is necessary for compressing it and transfer to other stations. The liquid hydrogen pump is operated at very high pressure up to 90 MPa. In our research, a reciprocating plunger pump is studied. Especially, a leakage in a liquid hydrogen pump is predicted using a finite element method. As a result, it was found that leak mass flow rates changed from 0.09 to 2.20 kg/h, when the gaps were given from 2 to 6 ㎛. Thus pump efficiencies were calculated from 99.9 to 97.9%, when the gaps changed from 2 to 6 ㎛. These results are useful for the design of the liquid hydrogen pump.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.1
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• pp.22-28
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• 2016

It is necessary to store and supply hydrogen isotopes for Tokamak operation. A storage and delivery system (SDS) is used for storing hydrogen isotopes as a metal hydride form. We designed and fabricated a depleted uranium (DU) bed to store hydrogen isotopes. The rapid storage of hydrogen isotopes is very important not only for safety reasons but also for the economic design and operation of the SDS. The delivery rate at the desorption temperatures without the operation of a dry pump was analyzed in comparison with that with the operation of the dry pump. The effect of the initial desorption temperatures on the dehydriding of the DU without the operation of the dry pump was measured. The effect of the initial desorption temperatures on the dehydriding of DU with the operation of the dry pump was also measured and analyzed. The primary pressure on the desorption temperatures without the operation of the dry pump was analyzed in comparison with that with the operation of the dry pump. The temperature gradient of the coil heater and the primary vessel was also analyzed. Our results will be used to develop pilot scale hydrogen isotope processes. It was confirmed that dehydriding of a medium-scale DU bed has enabled without the operation of the dry pump.

• Journal of the Korean Vacuum Society
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• v.15 no.1
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• pp.14-23
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• 2006

The scroll pump is widely used in ultra clean vacuum systems. However, there is no commonly available information on the hydrogen pumping characteristics of this pump, which creates a difficulty in determining whether the scroll pump can be used or not in a fusion experiment system where hydrogen ,is the main working gas. In this paper the experimental setup, measurement procedures, experimental results, and discussions on the pumping speed, the maximum compression ratio and the back-streaming properties of the scroll pump, especially for the hydrogen gas, are reported.

• Transactions of The Korea Fluid Power Systems Society
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• v.7 no.1
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• pp.1-5
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• 2010

This paper presents the experimental results of the radial piston type oil pump with new mechanism for a metal diaphragm hydrogen compressor. Generally, metal diaphragm type hydrogen compressor systems are operated by oil hydraulic power. In this system an oil compensating pump has been demanded to compensate for a leakage oil head chamber. The metal diaphragm type hydrogen compressor consists of an oil compensating pump, commonly used hydraulic piston pump and driven by main crank shaft. The radial piston type oil compensating pump with new rolling contacted piston mechanism is developed and experimented. The developed piston element of the radial piston pump consists of piston, steel ball, return spring, two check valves, eccentric cam and ball racer. In this study, designed 4 type pistons as and orifice hole. Operating characteristics and pressure ripple characteristics are tested under no load to 60bar loaded with every 20bar increasing step and pressure ripple and flow rate are experimentally investigated.

• Transactions of the Korean hydrogen and new energy society
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• v.4 no.1
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• pp.21-30
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• 1993

The operational characteristics of a metal hydride heat pump system are strongly dependent on the amound of hydrogen gas transferred by hydriding and dehydriding reactions between the reactors under dynamic conditions. A new metal hydride heat pump combined with hydrogen compressor was constructed and the dependency of its operating conditions on such as cycle time, amount of hydrogen to be transferred between two reacting metal hydride reactors, operating temperature, and heat transmission characteristics of the reactors was investigated to find the optimum operating efficiency. These conditions were also evaluated in connection with the cooling output and hydrogen compressor connected to the system in order to enhance the total efficiency.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.3
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• pp.240-246
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• 2014

In order to develop a universal cryogenic piston pump of small size for increasing utilization of liquid hydrogen, dynamic compression performance of piston pump were evaluated and improvements were also discussed for piston rod and piston tip. The cryogenic piston pump has crosshead structure and inclined cup shape piston tip. As the results, it was found that i) insulation of heat flow from piston-rod part is required for stable operation ii) improving the self-clearance adjustment effect of piston tip and reducing piston eccentricity were desirable to promote pumping pressure and operating range.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.5
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• pp.583-590
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• 2022

In this paper, the performance characteristics of the 2 vane pump for wastewater treatment were investigated using response surface method(RSM) with commercial computation fluid dynamics(CFD) software. Design variables of wastewater treatment pump were defined with the meridional plane of the 2 vane pump impeller. The objective functions were defined as the total head and the efficiency at the design flow rate. The hydraulic performance of optimum model was verified by numerical analysis and the reliability of the model was retained by comparison of numerical analysis and comparative analysis with the reference model.

• Transactions of the Korean hydrogen and new energy society
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• v.1 no.1
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• pp.24-30
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• 1989

Prototype metal hydride chemical heat pump was constructed using $LaNi_{4.7}Al_{0.3}$ for high temperature hydride and $MmNi_{4.15}Fe_{0.65}Al_{0.2}$ for low temperature hydride, and the effects of operating conditions on the performace of heat pump were investigaed to find out the optimum operating condition. Operating variables considered in this work were cycling time, temperature of hot air blown to the high temperature reactor, the amount of hydrogen gas with which the system was charged initially, and the flow rate of air at both reactors. Power of heat pump increases monotonically as $T_h$ increases, and shows maxima at 4.8H/M and 15-25 min in $H_2$ charged and cycling time respectively. Power of heat pump increases as air flow rate increases at low flow rate, but saturates to some value confined by heat flow rate through the hydride bed, These all phenomena can be explained by the modified power equation.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.3
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• pp.308-314
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• 2017

Jet pump in automotive fuel tank module is used to deliver fuel to fuel pump so that the pump is operated without aeration in suction side. In this study, three dimensional simulation model of jet pump is developed to understand performance variation over design parameters. Performance of jet pump is also investigated experimentally in terms of operating pressures. The experimental data is used to verify the three dimensional simulation model of jet pump. Verification results show that the three dimensional simulation model of jet pump is about 1% error with experiment. The simulations are conducted in terms of throat ratio and primary flow induction angle. As the throat ratio is increased, the flux ratio is trade-off at 3 times of throat diameter. On the other hand, as primary flow induction angle is increased, vapor pressure inside the nozzle is decreased. In summary, the results show that liquid jet pump has to be optimized over design parameters. Additionally, high velocity of induced flow is able to evolve cavitation phenomena inside the jet pump.

• Journal of the Korean Vacuum Society
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• v.10 no.3
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• pp.312-320
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• 2001

A Non-Evaporable Getter(NEG) pump was fabricated using Zr-V-Fe alloy modules to obtain $10^{-9}$ Pa range pressures. Pumping performances and activation characteristics were investigated and the pumping speeds for hydrogen, deuterium and carbon monoxide gases of the NEG pump were measured. And hydrogen desorption characteristics were examined during activation at $450^{\circ}C$. Futhermore the vacuum performance was compared with those of other high vacuum pumps as turbo-molecular pump, sputter-ion pump, and cryo pump by analyzing the residual gases of the system.