• 한국수소및신에너지학회논문집
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• 제26권3호
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• pp.234-240
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• 2015

In the face of the world's growing energy storage needs, liquid hydrogen offers a high energy density solution for the storage and transport of energy throughout society. A 5 L liquid hydrogen storage tank has been designed, fabricated and tested to investigate boil-off rate of liquid hydrogen. As the insulation plays a key role on the cryogenic vessels, various insulation methods have been employed. To reduce heat conduction loss, the epoxy resin-based insulation supports G-10 were used. To minimize radiation heat loss, vapor cooled radiation shield, multi-layer insulation, and high vacuum were adopted. Mass flow meter was used to measure boil-off rate of the 5 L cryogenic vessel. A series of performance tests were done for liquid nitrogen and liquid hydrogen to compare with design parameters, resulting in the boil-off rate of 1.7%/day for liquid nitrogen and 16.8%/day for liquid hydrogen at maximum.

• 한국추진공학회지
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• 제24권5호
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• pp.21-33
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• 2020

본 연구에서는 액체 수소를 연료로 사용하는 팽창기 사이클 로켓 엔진의 시스템 해석을 위한 프로그램을 개발하였다. 수소의 물성치는 온도에 따른 이성질체의 비율을 고려하였다. 팽창기 사이클 엔진의 개방형과 폐쇄형 형식에 따른 해석 절차를 수립하고 부품별 해석 방법을 제시하였다. 본 해석 프로그램의 검증을 위해 팽창기 사이클 엔진인 Vinci와 SE-21D를 대상으로 엔진 작동점의 성능 및 국외에서 수행된 해석 결과와 비교하였다. 해석 결과, 입력 정보가 부정확한 일부를 제외한 추진제의 질유량, 비추력, 동력과 같은 시스템의 주요 성능 인자는 1~2% 내외의 오차로 높은 정확도를 나타내었다.

• 한국수소및신에너지학회논문집
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• 제35권2호
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• pp.240-248
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• 2024

The purpose of this study is to investigate the freezing phenomena in printed circuit heat exchanger (PCHE) for cryogenic liquid hydrogen vaporizer. Local freezing phenomena in hot channels should be avoided in designing PCHE for cryogenic liquid hydrogen vaporizer. Hence, the flow and thermal characteristics of PCHE is experimentally investigated to figure out the conditions under when freezing occurs. To conduct lab-scale PCHE experiment, liquid nitrogen is used as a working fluid in cold channels instead of using liquid hydrogen. Glycol water is used as a working fluid in hot channels. Based on the experimental data, ratio between mass flow rates of cold channels and that of hot channels is proposed as contour map to avoid the freezing phenomena in PCHE.

• 한국수소및신에너지학회논문집
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• 제35권1호
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• pp.34-39
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• 2024

Korea government is trying to supply liquid hydrogen from another country to domestic The research for liquid hydrogen transportation and liquefaction plant of hydrogen underway for several years, and empirical research is also planned in the future. Along with the development of liquid hydrogen transport ship/liquefaction plant technology, the development of liquid hydrogen reception base technology must be carried out. In this study, a concept level liquid hydrogen receiving terminal is constructed based on the process of the LNG receiving terminal. Based on this, a study is conducted on the development of analysis technology for the amount of BOG (pipe, tank) generated during cooldown and unloading in the liquid hydrogen unloading line (loading arm to storage tank). The research results are intended to be used as basic data for the design and liquid hydrogen receiving terminal in the future.

• 한국수소및신에너지학회논문집
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• 제34권5호
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• pp.526-534
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• 2023

To evaluate the risk of leakage when using liquid hydrogen, a leakage test was conducted using liquid nitrogen in an outdoor environment rather than a laboratory environment. To assume a real-scale continuous leak, liquid nitrogen was allowed to leak for 5 minutes through a pipe with a diameter of 25.4 mm at a design spill rate of 60 L/min. The measurement system consisted of devices for climate conditions, LN2 spread and vapor clouds. The main experimental results are the liquid pool radius and the concentration of vapor cloud, and the radius of the liquid pool was compared with the numerical analysis results.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제31회 추계학술대회논문집
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• pp.463-466
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• 2008

액체 추진기관을 적용하는 무기체계는 용도가 점차 증가되는 추세에 있으며, 운용목적 및 환경에 따라 다양한 물성을 가진 액체연료의 수요도 많아지고 있다. norbornane 또는 dicyclopentane 구조를 포함한 고리탄화수소 화합물은 고밀도 고에너지 특성을 바탕으로 다양한 유도무기체계에 적용되고 있으며, 현재도 많은 분야에서 연구 대상이 되고 있다. 본 연구에서는 분자물질의 설계 및 이를 대상으로 합성한 다양한 고리형 탄화수소화합물의 물성을 분석하여 그 구조에 따라 밀도와 발열량등 이화학 특성이 어떤 경향을 나타내는지 알아보았다.

• 한국수소및신에너지학회논문집
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• 제31권1호
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• pp.41-48
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• 2020

The present study discussed the thermodynamic analysis of the hydrogen liquefaction process to build a hydrogen liquefaction pilot plant with a small capacity (0.5 ton/day). A 2-stage Brayton cycle utilizing LNG/LN2 cold energy was suggested to be built in Korea for the hydrogen liquefaction pilot plant with a small capacity. Thermodynamic analysis on the effect of various variables on the efficiency of hydrogen liquefaction process was performed. As a result, the CASE in which the ortho-para conversion catalyst was infiltrated inside the heat exchanger showed the best process efficiency. Finally, thermodynamic analysis was performed on the effect of turbo expander compression ratio on the hydrogen liquefaction process and it was confirmed that an optimal turbo expander compression ratio exists.

• 공업화학
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• 제24권4호
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• pp.412-415
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• 2013

상온 이온성액체 중 하나인 1-hexyl-3-methylimidazolium tetrafluoroborate을 이용하여 팔라듐이 담지된 탄소입자를 제조하였다. 제조된 입자는 hexafluoropropylene (HFP) 수소화 반응용 촉매로 사용되었다. 또한 최적의 수소화 반응공정을 개발하기 위하여 다양한 반응조건에서 반응을 수행하였다. 팔라듐의 함량의 경우 3 wt% 이상을 유지하고 이온성액체와 팔라듐전구체의 몰비가 1 : 1로 합성된 촉매가 우수한 수소화 반응성을 보였다. 반응조건의 경우 수소와 HFP의 유량비가 1.25 이상이고 $GHSV_{HFP}$는 50000 mL/g-h 이하일 때 전환율 100%를 달성하였다.

• 한국추진공학회지
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• 제14권2호
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• pp.63-70
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• 2010

본 연구에서는 액체로켓엔진 산화제로 과산화수소를 사용하기 위한 공급 설비 구축 및 세척 방법을 제시하고자 한다. 과산화수소를 추진제로 사용하기 위해서는 90% 이상의 고농도 과산화수소가 필요하며, 고농도 과산화수소의 공급 설비는 약간의 오염에도 민감하게 반응하는 과산화수소의 특성상 오염을 최소화해야 한다. 과산화수소 공급 설비의 오염을 최소화하기 위하여 공급 설비를 세척하고 세척된 공급 설비에 보호막을 입히는 표면안정화 절차를 확립하였다. 또한, 구축된 공급 설비는 누설 시험과 연소 시험 및 저장성 테스트를 통하여 안정성을 검증하였다.

• 한국수소및신에너지학회논문집
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• 제8권2호
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• pp.57-65
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• 1997

Thermal analysis has been performed to design a high-performance $LH_2$ vessel with about 1% per day evaporation loss. Analysis includes the combined insulations of MLI(Multi-Layer Insulation) and VCS (Vapor-Cooled Shield) under high vacuum. Combined insulation of MLI and VCS shows the existence of optimal location of VCS to minimize evaporation loss. Comparison of parallel-type DVCS (Double Vapor-Cooled Shield) and serial-type DVCS is also made to show the effectiveness of the system. The results indicate that the serial-type DVCS vessel is better than the parallel-type DVCS vessel with respect to overall evaporation loss. The combined insulation of SVCS (Single Vapor-Cooled Shield) with a partial MLI can give a similar performance characteristics compared to that with MLI and DVCS.