• Title/Summary/Keyword: 헬륨

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Preparation of Nanoporous Ceramic Membranes by Sol-gel Method and Characterization of Gas Permeation (졸-겔법에 의한 나노기공성 세라믹 막의 제조 및 기체투과 특성)

  • Lee, Yong-Taek;Choi, Ga-Young;Han, Hyuk-Hee
    • Membrane Journal
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    • v.18 no.2
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    • pp.176-184
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    • 2008
  • Nano-porous ceramic membranes was synthesized by the sol-gel method. Gas permeation of hydrogen and nitrogen was determined by single composition gas. Pore size $0.1{\mu}m$ and porosity 32% of flat type ${\alpha}-Al_2O_3$ substrate was manufactured. An intermediate ${\gamma}-Al_2O_3$ layer with pore size of 4 nm was formed by dip-coating. Polymeric silica sol was synthesized by acid catalyzed hydrolysis and condensation of tetra-ethyl-ortho-silicate. Supported membranes on alumina were prepared by dipping and calcining. He, $N_2$ permeation experiments with nanoporous sol-gel modified supported ceramic membranes were peformed to determine the gas transport characteristics. $He/N_2$ permselectivity around $100{\sim}160$ and helium permeation in the order of $10^{-7}mol/m^2{\cdot}s{\cdot}Pa$ were measured in the temperature range of $303{\sim}363K$.

High-Temperature Structural Analysis Model of the Process Heat Exchanger for Helium Gas Loop (II) (헬륨가스루프 시험용 공정열교환기에 대한 고온구조해석 모델링(II))

  • Song, Kee-Nam;Lee, Heong-Yeon;Kim, Chan-Soo;Hong, Seong-Duk;Park, Hong-Yoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.10
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    • pp.1455-1462
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    • 2010
  • PHE (Process Heat Exchanger) is a key component required to transfer heat energy of $950^{\circ}C$ generated in a VHTR (Very High Temperature Reactor) to the chemical reaction that yields a large quantity of hydrogen. Korea Atomic Energy Research Institute established the helium gas loop for the performance test of components, which are used in the VHTR, and they manufactured a PHE prototype to be tested in the loop. In this study, as part of the hightemperature structural-integrity evaluation of the PHE prototype, which is scheduled to be tested in the helium gas loop, we carried out high-temperature structural-analysis modeling, thermal analysis, and thermal expansion analysis of the PHE prototype. The results obtained in this study will be used to design the performance test setup for the PHE prototype.

A study on output power characteristic of selenium vapour multiline laser using isotope helium and helium filter (헬륨 동위원소 및 헬륨필터를 사용한 셀레늄증기 다중광선레이저의 출력특성에 관한 연구)

  • 최상태
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.18 no.2
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    • pp.16-22
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    • 2004
  • The paper presents the effects of output-coupling power and small signal gain of selenium vapour multiline laser by discharge of either to $^4$He or $^3$He. The purity of the He gas was improved with a special He-fille.. The result shows that compared with those of $^4$He, the output-coupling power and small-signal gain of $^3$He increase in the most of the lines. Especially, the small-signal gain of $^3$He for the strong lines (497.6 nm, 499.3 nm, 506.9 nm, 517.6 nm, 522.8 nm, 530.5 nm) lies about 30% higher than that of $^4$He, and the output-coupling power from doubles to triples.

Development of Calibration System of Helium Permeation Type Standard Leaks (헬륨 투과형 표준리크 교정장치 개발)

  • Hong S.S.;Lim I.T.;Shin Y.H.
    • Journal of the Korean Vacuum Society
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    • v.15 no.4
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    • pp.347-353
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    • 2006
  • A helium permeation type standard leak calibration system has newly developed by using dynamic gas expansion method. The measurement range was extended lower to $10^{-6}$ Pa L/s for participating CCM (Consultative Committee for Mass and Related Quantities) standard leak key comparison. For the system, pressure ratios of high and ultra-high vacuum chamber and porous plug conductance for helium gas were determined. By using the system, a permeation type standard leak of $5.6{\times}10^{-4}$ Pa L/s range was calibrated. The calibration result showed that the difference between standard commercial leak was 11.1 %.

Cooling of Cryogenic Liquids by Gas Helium Injection (I) (가스분사에 의한 극저온 액체의 냉각에 관한 연구 (I))

  • Song, Yi-Hwa;Choi, Young-Hwan;Kim, Yoo;Chung, Yong-Gahp;Cho, Nam-Kyung;Jeong, Sang-Kwon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2003.10a
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    • pp.141-144
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    • 2003
  • In this paper, to satisfy the temperature requirement of turbopump-inlet condition, the cooling of cryogenic propellant is performed at the simulated suction-line of the Launch Vehicle. The cooling method is by using Gas helium injection. This study investigates the effect of helium injection on the liquid nitrogen which simulates the liquid oxygen. By using helium injection, the subcooling of liquid nitrogen can be achieved within four minute when the ratio of gas volume flowrate to the volume of L$N_2$ is approximately v/v$_{L}$≒0.8min$^{-1}$ . .

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A Study of the Transient Characteristics of LRE Startup Using Several Starting Gases (다양한 구동가스를 사용한 액체로켓엔진의 시동특성 연구)

  • Moon, Yoon-Wan;Cho, Won-Kook;Seol, Woo-Seok
    • Aerospace Engineering and Technology
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    • v.7 no.2
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    • pp.170-175
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    • 2008
  • In this study, it was investigated that the characteristics of startup and compatibility using several type hot and cold gases. The characteristics of starting LRE by pyro starter was compared with that by a Helium spinner. The compatibility of pyro gas, a gaseous Helium, Hydrogen+Nitrogen mixture gas, and air was investigated by a simple 1D turbine analysis considered the properties of each gas and turbine efficiency. Most of them were compatible to start up the LRE however air was properly used only for low power mode of turbine.

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Rupture Safety Assesment of Bipropellant Propulsion System at High Pressure Testing (이원 추진 시스템 고압 시험시의 파열 안전성 고찰)

  • Chang, Se-Myong;Han, Cho-Young
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.6
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    • pp.605-611
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    • 2010
  • The geostationary satellite COMS is going to be launched in 2010, and, in the series of test, there are some high-pressure tests concerning the vessel tank filled with helium gas of hundreds atmospheric pressure. In this paper, authors evaluates risk associated with accidental rupture of the test system. Two possible scenarios are considered: 1) the 310-bar helium tank ruptures at the center of the acoustic chamber, and 2) the 116-bar reduced-pressure helium tank ruptures in the test room shielded by bullet-proof glasses. Using the theory of blast wave propagation and computational simulation, the dynamics of wave reflected in a confined space is investigated for highly complex unsteady flow physics.

Development Test of Pyro-Valve for Cryogenic Gaseous Helium in Pressurization System of Launch Vehicle (발사체 가압시스템용 극저온 헬륨가스 파이로밸브 개발시험)

  • Chung, Yong-Gahp;Han, Sang-Yeop;Cho, In-Hyun
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.11a
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    • pp.293-297
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    • 2009
  • Valves, which are used to supply or block the flow of cryogenic pressurant in the pressurization system of liquid-propellant propulsion system in a launch vehicle, are pneumo-actuated valve, solenoid valve, pyro-valve, etc. Both pneumo-actuated valve and solenoid valve have more complex structure and are heavier than pyro-valve. For this study, a couple of pyro-valves, which are applicable to cryogenic and high-pressure fluid (cryogenic gaseous helium), have a simple structure, and are comparably light, are designed, manufactured, and tested (proof-pressure/leakage tests, performance test, vibration test, helium supply tests).

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Analysis on the dielectric characteristics of various insulation gases (기체절연매질의 종류에 따른 절연파괴특성 분석)

  • Nam, Seok-Ho;Lim, Ji-Hye;Kang, Hyoung-Ku
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2010.06a
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    • pp.106-106
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    • 2010
  • 전력기기용 기체절연매질로서 일반적인 전력기기용 절연기체로는 공기와 $SF_6$, dry air 등이 사용되고 있으며, 초전도전력기기용 절연기체로는 기체헬륨과 기체네온 등이 주로 사용되고 있다. 본 연구에서는 일반적인 전력기기용 절연기체로 주로 사용되는 공기와 초전도전력기기용 절연기체로 사용되는 기체헬륨의 절연특성을 구 대 평판 전극을 이용하여 비교, 분석하였다. 실험에 사용된 구 대 평판 전극은 절연실험에 의한 기계적 손상을 최소화하기 위하여 스테인레스 스틸을 이용하여 제작하였으며, 공기와 기체헬륨 각각에 대하여 다양한 구 전극의 직경과 전극간격에 대한 절연실험이 수행되었다. 이러한 두 기체의 절연실험 결과를 분석하기 위하여 유한요소해석법을 사용하였다. 본 연구를 통하여 기체의 절연파괴특성은 절연기체의 최대전계에 대한 함수로 표현될 수 있다는 것을 알 수 있었으며, 절연파괴 특성 분석을 통하여 절연기체의 종류에 따른 다양한 전력기기의 절연설계법을 확인할 수 있었다. 또한 본 연구결과는 일반 전력기기뿐만 아니라 초전도전력기기의 절연설계법 확립에 도움이 될 것으로 기대된다.

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Helium Leak Test for the PLS Storage Ring Chamber (포항가속기 저장링챔버의 헬륨누설검사)

  • Choi, M.H.;Kim, H.J.;Choi, W.C.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.13 no.3
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    • pp.31-38
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    • 1993
  • The storage ring vacuum system for the Pohang Light Source (PLS) has been designed to maintain the vacuum pressure of $10^{-10}Torr$ which requires UHV welding to have helium leak rate less than $1{\times}10^{-10}Torr{\cdot}{\ell}/sec$. In order to develop new technique (PLS) welding technique), a prototype vacuum chamber has been welded by using Tungsten Inert Gas welding method and all the welded joints have been tested with a non-destructive method, so called helium leak detection, to investigate the vacuum tightness of the weld joints. The test was performed with a detection limit of $1{\times}10^{-10}Torr{\cdot}{\ell}/sec$ for helium and no detectable leaks were found for all the welded joints. Thus the performance of welding technique is proven to meet the criteria of helium leak rate required in the PLS Storage Ring. Both the principle and the procedure for the helium leak detection are also discussed.

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