• Title/Summary/Keyword: 연료탱크

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Analysis and Flight Test of XKO-1 Store Separation (저속통제기 외부장착물 분리해석 및 비행시험)

  • Lee, Seung-Soo;Kim, Sang-Jin;Kim, Myung-Seong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.32 no.5
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    • pp.24-29
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    • 2004
  • In this paper, we summarize the results of free drop wind tunnel test, separation analysis and flight test in order to verify the safety during the separations of an external fuel tank and the LAU-131 rocket launcher from XKO-l. The wind tunnel test was conducted to show the safety in free drop of the stores and to gather the trajectory data for fine tune of MSAP(Multi-body Separation Analysis Program). The enhanced MSAP was then used to predict the trajectories of the stores with and without the ejector forces. A correlation of MSAP results for free drop case was also made to show the safety of jettison with the free drop type bomb rack. Moreover, the flight test was conducted. and its results were compared to analysis results. Finally, the safe jettison boundary was determined from the flight test.

Development of Performance Test Procedure for the Excess Flow Valve for Buried Piping for the Domestic LPG Mass Supply System (국내 LPG 집단공급시설 환경에 적합한 매몰배관용 과류차단밸브 성능시험 절차 개발)

  • Jang, Chanyeong;Lee, Ugwiyeon;Lee, Jinhan
    • Journal of the Korean Institute of Gas
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    • v.22 no.6
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    • pp.16-27
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    • 2018
  • Since 2014, the Korean government has begun distributing LPG pipelines and LPG tankers to mountainous or island areas where it is difficult to open urban gas supply chains. When installing LPG supply facilities at village level and county level, it supplied consumers with 10 times higher quasi-low pressure (25 kPa to 100 kPa) than conventional gas supply pressure, increasing the risk of gas accident. Due to the pressure that is 10 times higher than the conventional gas supply pressure, large amounts of gas are released at a faster rate when leaked. In order to secure safety of quasi-low-pressure gas pipes, excess flow valves for quasi-low-pressure gas pipes are not developed and are not supplied in Korea. Therefore, Korea Gas Safety Corporation is investigating the performance standards and products of the excess flow valves in order to localize the excess flow valves.

Computational Simulation of Lightning Strike on Aircraft and Design of Lightning Protection System (항공기 낙뢰 전산 시뮬레이션 및 보호시스템 설계)

  • Kim, Jong-Jun;Baek, Sang-Tae;Song, Dong-Geon;Myong, Rho-Shin
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.44 no.12
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    • pp.1071-1086
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    • 2016
  • The safety of aircraft can be threatened by environmental factors, such as icing, turbulence, and lightning strike. Due to its adverse effects on aircraft structure and electronic components of aircraft, lightning strike is one of the biggest hazards on aircraft safety. Lightning strike can inject high voltage electric current to the aircraft, which may generate strong magnetic field and extreme hot spots, leading to severe damage of structure or other equipment in aircraft. In this work, mechanism of lightning strike and associated direct and indirect effects of lightning on aircraft were studied. First, on the basis of aircraft lightning regulations provided by Aerospace Recommended Practice (ARP), we considered different lightning waveform and zones of an aircraft. A coupled thermal-electrical computational model of ABAQUS was then used for simulating flow of heat and electric current caused by a lightning strike. A study on fuel tank, with and without lightning protection system, was also conducted using the computational model. Finally, electric current flow on two full scale airframes was analyzed using the EMA3D code.

Study of Failure Examples for Emission Gas Control System in Gasoline Engine (가솔린 엔진 배출가스 제어장치에 대한 고장사례 고찰)

  • Lee, Il Kwon;Lee, Jong Ho;Lee, Young Suk;Youm, Kwang Wook;han, Jae Oh;Lim, Ha young
    • Journal of the Korean Institute of Gas
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    • v.20 no.6
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    • pp.37-42
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    • 2016
  • The purpose of this paper is to study for the emission gas control of passenger car. The first example, the PCSV never open when operating condition, but it opened by causing malfunction because of trouble. As a result, the purge gas entered into surge tank, a mount of fuel was displayed with excessive supply on tester. Therefore, it certified the bad-condition of the engine when idling by decreasing of fuel injection quantity from engine ECU. The second example, the hose activating a EGR valve didn't supply the vacuum pressure because of assembling the other part. Thus, it knew the bad-condition of engine that the EGR valve would not work normally by leaking with the other port. The third example, as the rear oxygen sensor of two sensor were fault-installing by changing the sensor of other a car it could not detect of oxygen quantity. Finally, it found the phenomenon of abruptly decreasing vehicle speed when braking a car. Therefore, the system including with emission control has to drastically manage by maximizing condition to role decreasing the emission gas.

A Numerical Study on Ventilation Characteristics of Factors Affecting Leakages in Hydrogen Ventilation (누출 수소 환기에 영향을 미치는 요인별 환기 특성에 관한 수치해석적 연구)

  • Lee, Chang-Yong;Cho, Dae-Hwan
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.28 no.4
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    • pp.610-619
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    • 2022
  • Hydrogen is emerging as an alternative fuel for eco-friendly ships because it reacts with oxygen to produce electrical energy and only water as a by-product. However, unlike regular fossil fuels, hydrogen has a material with a high risk of explosion due to its low ignition point and high flammability range. In order to safely use hydrogen in ships, it is an essential task to study the flow characteristics of hydrogen leakage and diffusion need to be studied. In this study, a numerical analysis was performed on the effect of leakage, ventilation, etc. on ventilation performance when hydrogen leaks in an enclosed space such as inside a ship. ANSYS CFX ver 18.1, a commercial CFD software, was used for numerical analysis. The leakage rate was changed to 1 q, 2 q, and 3 q at 1 q = 1 g/s, the ventilation rate was changed to 1 Q, 2 Q and 3 Q at 1 Q = 0.91 m/s, and the ventilation method was changed to type I, type II, type III to analyze the ventilation performance was analyzed. As the amount of leakage increased from 1 q to 3 q, the HMF in the storage room was about 2.4 to 3.0 times higher. Furthermore, the amount of ventilation to reduce the risk of explosion should be at least 2 Q, and it was established that type III was the most suitable method for the formation of negative pressure inside the hydrogen tank storage room.

A Preliminary Study on the Source Fingerprints of Volatile Organic Compounds (휘발성유기화합물의 배출원 구성물질 성분비에 관한 기초 연구)

  • 이영재;이학성;강병욱;신대윤
    • Journal of Environmental Science International
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    • v.12 no.4
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    • pp.487-496
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    • 2003
  • The purpose of this study was to develop the preliminary source fingerprints of volatile organic compounds (VOC). The source categories studied were vehicles, gasoline vapor, gasoline storage tank, coating, dry cleaning and road covering. The source samples were collected using 6L electro-polished stainless steel canisters for about 20 seconds. From this study, the main component emitted from VOC sources in Korea was toluene. The toluene proportion for road covering, vehicles, coating and gasoline vapor were 35, 18, 16 and 5%, respec- tively. The C$_2$-C$\sub$5/ alkane and alkene compounds were mainly emitted from vehicles, gasoline vapor and gasoline storage tank. The main compounds of coating were m/p-xylene(34%), toluene(16%), 1,2,4-TMB(10%) and o-xylene(9%), which are aromatic hydrocarbons. In the case of dry cleaning, nonane(41%), 1,2,4-TMB (22%) and 1,3,5-TMB(13%) were mainly emitted.

Reviews on the Studies of MTBE Contaminants in Groundwater

  • 이지훈;이진용;천정용;이강근
    • Journal of the Korean Society of Groundwater Environment
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    • v.7 no.1
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    • pp.55-58
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    • 2000
  • Methyl tertiary butyl ether (MTBE) is a gasoline additive that boosts the oxygen content in fuel (an oxygenate), resulting in less air-polluting carbon monoxide being released from vehicle exhaust systems. Then, groundwater contamination problems have been developed in areas where the chemical is used. Common sources of water contamination by MTBE include leaking underground gasoline storage tanks and leaks and spills from above ground fuel storage tanks, etc.. Studies on the chemical and these problems are going on abroad vigorously. These studies should be performed in our country as well more actively. This paper reviews on articles on these studies and focuses on the identification of the chemical as a groundwater contamination source.

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Design and Assessment of Reliquefaction System According to Boil Off Gas Reliquefaction Rate of Liquefied Hydrogen Carrier (액화수소 운반선의 증발가스 재액화 비율에 따른 재액화 시스템의 설계 및 평가)

  • Cho, Wook-Rae;Lee, Hyun-Yong;Ryu, Bo-Rim;Kang, Ho-Keun
    • Journal of Navigation and Port Research
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    • v.44 no.4
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    • pp.283-290
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    • 2020
  • BOG (Boil Off Gas) generation is unavoidable in the liquefied hydrogen carrier, and proper measures are necessary to prevent pressure problems inside the cargo tank. The BOG can be used as propulsion fuel for ships, and the remaining parts used for propulsion must be effectively managed, such as in the form of reliquefying or burning. This study proposes an BOG reliquefaction system optimized for a 160,000 m3 liquefied hydrogen carrier with a hydrogen propulsion system. The system comprises a hydrogen compression and helium refrigerant section, and increases the efficiency by effectively using the cold energy of the BOG discharged from the cargo tank. In this study, the system was evaluated through the exergy efficiency and SEC (Specific Energy Consumption) analysis according to the rate of the reliquefaction of the BOG while the hydrogen BOG with a supply temperature of -220℃ entered the reliquefaction system. As a result, it showed SEC of 4.11 kWh/kgLH2 and exergy efficiency of 60.1% at the rate of reliquefaction of 20%. And the parametric study of the effects of varying the hydrogen compression pressure, inlet temperature of the hydrogen expander, and the feed hydrogen temperature was conducted.

A Study on Development of Mobile LNG Yard Tractor Refueling Standards (이동식 LNG 야드트랙터 충전 기준 개발 연구)

  • Ryou, Young-don;Yu, Chul-hee;Koo, Bon-deuk;Lee, Dong-won
    • Journal of the Korean Institute of Gas
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    • v.22 no.6
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    • pp.59-64
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    • 2018
  • As part of measures to reduce fine dust, the government is promoting a project to convert the fuel of Yard Tractors(YT, tractors operated at ports), from diesel to LNG (Liquefied Natural Gas). While a port having a small number of yard tractors, it is not proper to construct a stationary LNG fueling station and supply LNG to YT due to a problem of BOG (Boil off gas) generation. Therefore, it is necessary to make a regulation and a standard on mobile LNG YT refueling station installation and inspection as an alternative. In this study, we have investigated domestic and foreign mobile LNG refueling cases and refueling standards, including the USA and Europe. In addition, we have suggested the risk reduction method according to the cause after investigation of the cause of LNG accidents. And last, based on the proposed risk reduction measures, we have proposed an amendment to the Regulation of the Urban Gas Business Law in Korea. The proposed mobile LNG YT refueling amendment of the Regulation includes ; maintenance of the safety distance from the protection facility, installation of an interlock device to prevent refueling in places other than the authorized place, installation of the identification system through biometrics, separation of the tank lorry and tow vehicle before refueling, checking the wheel fixed status of tank lorry before refueling, construction of the impounding area, safety measures before, during and after refueling, etc. The safety standards proposed in this study could be used as a reference in establishing standards for mobile LNG vehicle refueling in the near future.

Pogo Suppressor Design of a Space Launch Vehicle using Multiple-Objective Optimization Approach (다목적함수 최적화 기법을 이용한 우주발사체의 포고억제기 설계)

  • Yoon, NamKyung;Yoo, JeongUk;Park, KookJin;Shin, SangJoon
    • Journal of the Korean Society of Propulsion Engineers
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    • v.25 no.1
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    • pp.1-11
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    • 2021
  • POGO is a dynamic axial instability phenomenon that occurs in liquid-propelled rockets. As the natural frequencies of the fuselage and those of the propellant supply system become closer, the entire system will become unstable. To predict POGO, the propellant (oxidant and fuel) tank in the first stage is modeled as a shell element, and the remaining components, the engine and the upper part, are modeled as mass-spring, and structural analysis is performed. The transmission line model is used to predict the pressure and flow perturbation of the propellant supply system. In this paper, the closed-loop transfer function is constructed by integrating the fuselage structure and fluid modeling as described above. The pogo suppressor consists of a branch pipe and an accumulator that absorbs pressure fluctuations in a passive manner and is located in the middle of the propellant supply system. The design parameters for its design optimization to suppress the decay phenomenon are set as the diameter, length of the branch pipe, and accumulator. Multiple-objective function optimization is performed by setting the energy minimization of the closed loop transfer function in terms of to the mass of the pogo suppressor and that of the propellant as the objective function.