• 한국수소및신에너지학회논문집
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• 제32권3호
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• pp.189-195
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• 2021

A compressed hydrogen tank is to be repressurized to 40 bar by being connected to a high-pressure line containing hydrogen at 50 bar and 25℃. Hydrogen filling time and the corresponding hydrogen temperature has been estimated when the filling process stopped according to several thermodynamic models. During the process of cooling the hydrogen tank, hydrogen temperature and pressure vs. time estimation was performed using Aspen Dynamics. Filling time, hydrogen temperature after filling hydrogen gas, cooling time and the final tank pressure after tank filling process have been completed according to the thermodynamic models are almost same.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.353-358
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• 2010

High pressure gas is a widely used storage mode for hydrogen fuel. A typical hydrogen tank that is charged with hydrogen gas can function as a hydrogen supply source in a large number of applications. The filling process of a high-pressure hydrogen tank should be reasonably short. However, when the fill time is short, the maximum temperature in the tank increases. Therefore the process should be designed in such a way to avoid high temperatures in the tank because of safety reasons. The paper simulates the fast filling process of hydrogen tanks using Computational Fluid Dynamics method. The local temperature distribution in the tank is obtained. Results obtained are compared with available experimental data. Further work is going on to improve the accuracy of the calculations.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 추계학술대회 논문집
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• pp.302-305
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• 2007

In recent years, many researches on new storage media with high capacity and information are developing. For manufacture of optical storage with high capacity, the injection molding process is generally used. In order to increase the filling ratio of the injection molding structure, the injection molding process required for high injection pressure, packing pressure and temperature control of the mold. However, conventional injection molding process is difficult to increase the filling ratio using injection master with the range of several nanometers and high aspect ratio. In order to improve and increase filling ratio of nano-structure with high aspect ratio, the active temperature control of injection mold was used. Experimental conditions were used injection pressure, time and temperature. Consequently, by using the peltier device into injection mold, we carried out the efficient and active temperature control of mold at low cost.

• 한국해양공학회지
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• 제24권6호
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• pp.30-33
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• 2010

This study presents the effect of filling ratio on sloshing impact pressure. The experiment was done with three filling ratios of 20%, 70%, and 95% of the tank height. The input of the motion was regular excitation. The total number of sensors in use were 53. They were installed on tank top and tank wall. The maximum pressures and the average of one third highest impact pressures for the whole pressure sensors were investigated. The result shows clearly the location of sensors which are exposed to the high impact pressures for different filling ratios. The characteristics of the impact patterns for three filling ratios were also examined.

• 한국수소및신에너지학회논문집
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• 제32권3호
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• pp.163-171
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• 2021

Securing energy sources is a key element essential to economic and industrial development in modern society, and research on renewable energy and hydrogen energy is now actively carried out. This research was conducted through experiments and analytical methods on the hydrogen filling process in the hydrogen storage tank of the hydrogen charging station. When low-temperature, high-pressure hydrogen was injected into a high-pressure tanks where hydrogen is charged, the theoretical method was used to analyze the changes in temperature and pressure inside the high-pressure tanks, the amount of hydrogen charge, and the charging time. The analysis was conducted in the initial vacuum state, called the First Cycle, and when the residual pressure was present inside the tanks, called the Second Cycle. As a result of the analysis, the highest temperature inside the tanks in the First Cycle of the high-pressure tank increased to 442.11 K, the temperature measured through the experiment was 441.77 K, the Second Cycle increased to 397.12 K, and the temperature measured through the experiment was 398 K. The results obtained through experimentation and analysis differ within ±1%. The results of this study will be useful for future hydrogen energy research and hydrogen charging station.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.386-391
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• 2006

This study presents experimental results of sloshing phenomenon done on rectangular box. A simple harmonic excitation was done on the box. Two kinds of filling ratio, 20% and 30% of height, were tested. A total of 15 pressure sensors were installed to monitor the impact pressure. Each test was repeated for 20 times to ensure the repeatability. The high speed camera captured the flaw filed and the corresponding pressure were synchronize with video signal so that the video image can help the interpretation of the impact pressure. The two filling ratio made difference in the flaw characteristic and impact pressure. The use of high speed camera made it possible to understand the bubble generation mechanism. The pressure time histories were presented.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.769-773
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• 2002

The die easting process was used to manufacture a motor housing for automobile. Specially automobile parts were required light and high strength. Therefore simulations have been carried out die casting process of motor housing. In this paper, we investigated about characteristics of the die casted motor housing with HPDC(High Pressure Die Casting) process. Also the MAGMAsoft was used as computer simulation code and used material was ADC12(Aluminum Die Casting Alloy). We present the results of filling behavior and solidification process of a motor housing cast. The analysis results obtained about filling behavior and solidification of cast showed good agreement with test results.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.142-149
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• 2003

Blind hydraulic backfilling is a commonly used technique for subsidence control of the strata over unapproachable waterlogged underground excavations. In this investigation model studies on all the three variants of this technique, namely, hydro-pneumatic or air-assisted gravity backfilling, pumped-slurry backfilling and simple gravity backfilling, have been carried out in fully transparent models of the underground excavations. On examination of the filling process, it was revealed that in all the three cases, the basic process of filling occurs by sand transport along one or more meandering channels. The relative influence of sand, water and air flow rates on the area of filling from a single inlet point and the hydraulic pressure loss per unit length were studied in details. In hydro-pneumatic backfilling process, the air bubbles while moving upward through the meandering channels provide an additional buoyant force over and above the available hydraulic head. In this way the area of filling from a single borehole may be quite large even at small flow rates of water. During actual field implementation the injected air, if not released completely from the rise side holes, may cause troubles by way of creating potholes on the surface. The pumped-slurry technique has shown its capability of filling a relatively larger area at faster rate, especially when high-volume, low-pressure method was selected. But simple gravity filling was also found to be equally effective method as slurry pumping, especially when flow rates were high. In the second and third method discussed above, examination of variations of injection pressure was also done and its relation with physical phenomenon was also attempted. Some empirical relationships were also developed using multivariate regression with a view to help the practicing engineers.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.3-7
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• 2002

The die casting process was used to manufacture a alternator housing for automobile. Specially automobile parts were required light and hight strength. Therefore simulation have been carried out die casting process of the alternator housing. In this paper, we investigated about characteristics of the die casted alternator housing the HPDC(High Pressure Die Casting) process. Also we designed the die casting die with the simulation results of the alternator housing. The MAGMAsoft and Auto-CAD was used as computer simulation and design code and used material was ADC12(Aluminum Die Casting Alloy). We present the results of filling behavior and design of die process of the alternator housing cast. The result obtained about filling behavior and design of die of the cast showed good agreement with test result.

• Journal of Advanced Research in Ocean Engineering
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• 제3권1호
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• pp.41-52
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• 2017

This paper presents a numerical and experimental study of sloshing loads on liquefied natural gas (LNG) vessels. Conventional LNG carriers with membrane-type cargo systems have filling restrictions from 10% to 70% of tank height. The main reason for such restrictions is high sloshing loads around these filling depths. However, intermediate filling depths cannot be avoided for most LNG vessels except the LNG carrier. This study attempted to design a membrane-type LNG tank with a modified lower-chamfer shape that allows all filling operations. First, numerical sloshing analysis was carried out to find an efficient height of the lower-chamfer that can reduce sloshing pressure at partially filled conditions. The numerical sloshing analysis program SHI-SLOSH was used for numerical simulation; this program is based on SOLA-VOF. The effectiveness of the newly designed tanks was validated by 1:50-scale three-dimensional tank tests. A total of three different tanks were tested: a conventional tank and two modified tanks. As test conditions, various filling depths and wave periods were considered, and the same test conditions were applied to the three tanks. During the test, slosh-induced dynamic pressures were measured around the corners of the tank wall. The measured pressure data were post-processed and the pressures of the three different tanks were statistically compared in several ways. Experimental results show that the modified tanks were quite effective in reducing sloshing loads at low filling conditions. This study demonstrated the possibility of all filling operations for LNG cargo containment systems.