• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.62-65
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• 2011

액체로켓엔진용 극저온 산화제 고압 배관 기술 개발을 위해 시제품을 제작하였다. 기술 개발 시제품은 체결용 플랜지, 직관, 곡관, 벨로우즈, 분기구로 구성하였다. 액체로켓엔진용 극저온 산화제 고압 배관은 터보펌프에서 토출된 고압의 극저온 산화제를 연소기로 공급하는 경로이므로 극저온, 고압의 작동환경에서 구조적 안정성을 가져야 한다. 따라서 본 제작공정 개발에서는 극저온을 고려한 구조해석을 수행하여 적합한 소재를 선정하였으며, 공정개발과 특수공정을 적용하여 시제품을 제작한 후 구조강도 시험을 수행하였다. 본 개발을 통해 액체로켓엔진에 적용되는 극저온 산화재 고압배관을 위한 기술적 기반과 소재 응용기술, 향후 고성능 대형 액체로켓엔진에 적용하기 위한 공정개발을 완료하였다.

• Vacuum Magazine
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• v.2 no.3
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• pp.23-29
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• 2015

Cryopump(cryogenic pump), with integrating cryogenic skills into vacuum technology, is the most popular high vacuum pump system, which is widely used at the commercial vacuum industries with TMP. Hyunmin GVT, Inc. is the domestic unique professional manufacturer of the cryopump systems. About ten years ago, while GVT succeeded in domestically producing cryopump systems, this high technology initiated from US became localized completely. But the process of the home production was not easy. It was possible through many trials and errors and after efforts and sacrifices of our engineers. Now many users and customers have the benefit of the advantage and excellence of the domestic cryopump systems. Especially, these days GVT is conducting researches and developments regarding low vibration cryopump and large-sized CWPs and Cryo-TMPs.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.376-381
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• 2012

Natural gas is converted in to LNG by chilling and liquefying the gas to the temperature of $-162^{\circ}C$, when liquefied, the volume of natural gas is reduced to 1/600th of its standard volume. This gives LNG the advantage in transportation. The pressure dorp of the cascade liquefaction cycle was investigated and simulated using HYSYS software. The simulation results showed that the pressure drop in the LNG heat exchanger is set to 50 kPa considering the increase in the compressor work of cryogenic cascade liquefaction cycle.

• Journal of Digital Convergence
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• v.11 no.3
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• pp.311-316
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• 2013

In order to maximize an efficient management of human cell resource under the cryogenic environments, in this paper, a middleware is introduced to support the function for multiple-perceiving RFID tags of intelligent sample case which can share medical information between sensor network devices. Optimized user interface is also designed for that. On based of the designing, special tasks required of a genetic resource working process can be processed on Complex Machine.

• Journal of the Korea Safety Management & Science
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• v.4 no.2
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• pp.223-235
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• 2002

This paper presents some indirect physical evidences indicating that reduced friction occurs in an economical cryogenic machining process, in which LN2 is applied selectively in well-controlled jets to the localized cutting zone. These evidences include cutting force components, tool wear rate and chip morphology. LN2 reduced the tool wear rate to a great extent and elongated the tool life up to four times compared to emulsion cooling. The friction reduction was further reflected in larger shear angle and less secondary deformation in the chip microstructures. This study also found that the effectiveness of LN2 lubrication depends on the approach how LN2 is applied.

• Progress in Superconductivity and Cryogenics
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• v.12 no.1
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• pp.66-70
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• 2010

The operational temperature range of thermosiphon is generally limited from the critical point to the triple point of the working fluid to maintain two-phase state. Thermosiphon with mixed working fluid has a potential to widen the operational temperature range. In this study, the physical behavior of mixed working fluid during the transient operation of thermosiphon was analyzed with temperature-mole fraction diagram. The condenser and the evaporator temperature variations were explained by the dew line and the bubble line of the mixture. It is encouraging that the thermosiphon operation commences early with larger fraction of high boiling point component, but the temperature gap between the condenser and the evaporator due to the separation of two components has a negative effect on the officient cool down process.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.3
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• pp.77-81
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• 2012

In a cryogenic propellant tank the pressurant is contracted due to heat loss and the propellant itself evaporates. On a restartable propulsion system such phenomena are more intensive because the propellant contacts with the pressurant on the larger surface during the coast flight. Such heat and mass transfer phenomena should be considered for estimating the amount of pressurant. On the hypothesis that the heat and mass transfer quasi-equilibrium is achieved during the coast flight, the calculation process of the equilibrium pressure is presented. On the process the amount of loaded helium on the Falcon-1 second stage is calculated.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.3
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• pp.28-32
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• 2011

The safety of transporting equipment in a cryogenic condition is one of important problems under the circumstances that the application weight of natural gas is gradually increasing. As a larger disaster may be generated by leakage of oil or gas from valves in case of fire occurrence of a ship, the present research applied a numerical analysis method on thermal stress distribution and deformation, etc. to the design of ball valves satisfying fire safety test's specification(API607) to prevent this. In addition, the present research progressed fire safety tests and compared the test result with numerical analysis results. The Max stress by parts was confirmed through thermal analysis of major parts to evaluate safety. The fire safety test was progressed according to the regulation of API607.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.201-205
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• 2011

In a cryogenic propellant tank the pressurant is contracted due to heat loss and the propellant itself evaporates. On a restartable propulsion system such phenomena are more intensive because the propellant contacts with the pressurant on the larger surface during the coast flight. Such heat and mass transfer phenomena should be considered for estimating the amount of pressurant. On the hypothesis that the heat and mass transfer quasi-equilibrium is achieved during the coast flight, the calculation process of the equilibrium pressure is presented. On the process the amount of loaded helium on the Falcon-1 second stage is calculated.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.279-281
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• 1997

The properties of Platinum dry etching were investigated in MICP(Magnetized Inductively Coupled Plasma). The problem with Platinum etching is the redeposition of sputtered Platinum on the sidewall. Because of the redeposits on the sidewall, the etching of patterned Platinum structure produce feature sizes that exceed the original dimension of the PR size and the etch profile has needle-like shape.[1] Generally, $Cl_2$ plasma is used for the fence-free etching.[1][2][3] The main object of this study was to investigate a new process technology for the fence-free Pt etching. Platinum was etched with Ar plasma at the cryogenic temperature and with Ar/$SF_6$ plasma at room temperature. In cryogenic etching, the height of fence was reduced to 20% at $-190^{\circ}C$ compared with that of room temp., but the etch profile was not fence-free. In Ar/$SF_6$ Plasma, chemical reaction took part in etching process. The trend of properties of Ar/$SF_6$ Plasma etching is similar to that of $Cl_2$ Plasma etching. Fence-free etching was possible, but PR selectivity was very low. A new gas chemistry for fence-free Platinum etching was proposed in this study.