• Journal of the Korean Institute of Gas
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• v.15 no.1
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• pp.30-34
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• 2011

This paper presents a strength safety evaluation of composite pressure container for hydrogen fuel tanks with a storage capacity of 104 liter and 70MPa pressure. The carbon fiber composite container is manufactured by an aluminum liner of Al6061-T6 and composite multi-layers of hoop winding layer in circumferential direction, $12^{\circ}C$ inclined winding layer and $70^{\circ}C$winding layer in helical direction respectively. The FEM results on the strength safety of composite fuel tanks were evaluated with a criterion of design safety of US DOT-CFFC and KS B ISO 11119-2 codes. The FEM computed results indicate that the proposed design model of 104 liter composite container is safe based on two strength safety codes. But, the computed results of carbon fiber fuel tanks based on US DOT-CFFC code is safer compared with that of KS B ISO 11119-2. Thus the hydrogen gas pressure container of 70MPa may be evaluated and designed by US DOT-CFFC code for more strength safety.

• Journal of the Korean Institute of Gas
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• v.14 no.2
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• pp.40-46
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• 2010

In this study, the integrated control and safety management system for a super-large LNG membrane storage tank has been presented based on the investigation and analysis of measuring equipments and safety analysis system for a conventional LNG membrane storage tank. The integrated control and safety management system, which may increase a safety and efficiency of a super-large LNG membrane storage tank, added additional pressure gauges and new displacement/force sensors at the steel anchor between an inner tank and a prestressed concrete structure. The displacement and force sensors may provide clues of a membrane panel failure and a LNG leakage from the inner tank. The conventional leak sensor may not provide proper information on the membrane panel fracture even though LNG is leaked until the leak detector, which is placed at the insulation area behind an inner tank, send a warning signal. Thus, the new integrated control and safety management system is to collect and analyze the temperature, pressure, displacement, force and LNG density, which are related to the tank system safety and leakage control from the inner tank. The digital data are also measured from measurement systems such as displacement and force of a membrane panel safety, LNG level and density, cool-down process, leakage, and pressure controls.

• Proceedings of the KAIS Fall Conference
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• 2012.05b
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• pp.637-639
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• 2012

본 논문에서는 대형 공조기기에서 냉매의 회수시간을 단축하기 위해 진공과 가압방식을 겸용하면서 작업 시 이동이 손쉽게 소형으로 회수 및 충전이 가능할 수 있는 냉매 회수 및 충전 전용기 개발을 하고자 한다. 냉매회수시스템의 작업과정은 냉매회수 장치와 냉동기의 증발기 하부에 충진용 밸브를 호스로 연결하고 진공펌프를 운전하여 저장 탱크 내에 부착된 압력계가 진공상태가 될 때까지 액냉매를 회수 한 후, 자체적으로 증발, 흡입, 액화시켜 탱크내의 온도와 압력을 낮추어 액화된 냉매를 저장탱크로 회수하는 장치로 구성되어 있다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.50.2-50.2
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• 2011

자동차용 CNG 연료탱크의 복합재료 중앙부 표면에 150 kHz 공진형 음향방출센서를 부착하고, 물을 매질로 하여 용기의 내압을 단계적으로 상승시켜 가면서 각 단계에서 일정시간 압력을 유지시키고 그 때 발생하는 음향방출신호를 획득하였다. 이 때 획득한 음향방출신호의 amplitude, count, duration 및 risetime 등과 같은 음향방출 변수들의 분포를 살펴본 결과 복합재료 압력용기의 손상메커니즘을 추정하고 손상정도를 평가하는데 유용하였다.

• Journal of the Korean Institute of Gas
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• v.15 no.5
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• pp.37-41
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• 2011

This paper presents the strength safety of a hydrogen gas composite fuel tank, which is analyzed using a FEM based on the criterion of US DOT-CFFC and Korean Standard. A hydrogen gas composite tank in which is fabricated by an aluminum liner of 6061-T6 material and carbon fiber wound composite layers of T800-24K is charged with a filling pressure of 70MPa and a gas storage capacity of 130 liter. The FEM results indicated that von Mises stress, 255.2MPa of an aluminum liner inner tank is low compared with that of 95% yield strength, 272MPa. And a carbon fiber stress ratio of a composite fuel tank is 3.11 in hoop direction and 3.04 in helical direction. These data indicate that a carbon fiber gas tank is safe in comparison to that of a recommended criterion of 2.4 stress ratio. Thus, the proposed composite tank with 130 liter capacity and 70MPa filling pressure is usable in strength safety.

• Journal of the Korean Institute of Gas
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• v.16 no.3
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• pp.16-21
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• 2012

In this study, the strength safety for 110 liter hydrogen fuel storage tank with 70MPa filling pressure has been analyzed using a FEM technique. The strength safety of a composite fuel tank in which is fabricated by an aluminum liner of 6061-T6 and carbon fiber wound composite layers of T800-24K and T700-12K of Toray, and MR60H-24P of Mitsubishi Ray has been investigated based on the criterion of a strength safety of US DOT-CFFC and Korean Standard. The FEM computed results on the strength safety of 70MPa hydrogen gas tank showed that the hydrogen fuel storage tank in which is fabricated by T800-24K and T700-12K of Toray, and MR60H-24P of Mitsubishi Ray is safe because those two carbon fibers have very similar material properties. But, the composite storage tank with a filling pressure of 70MPa in which is fabricated by T700-12K of Toray may not guaranty the strength safety, and thus this study recommends a composite hydrogen fuel tank under 60MPa.

• Journal of the Korean Institute of Gas
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• v.26 no.6
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• pp.9-15
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• 2022

In order to verify the durability of the high-pressure hydrogen tank in the operating pressure range, a hydraulic rupture test should be performed. However, if the bubbles generated by the initial injection process of water are attached to the inner wall of the tank and remain, a sudden pressure change of the bubbles during the rupture of the pressurized tank may cause shock and noise. Therefore, in this study, the flow velocity required to remove the bubbles remaining on the inner wall of the tank was predicted through simplified formulas, and the shape of the injection nozzle to maintain the flow velocity was determined based on the shape of the hydrogen tank for the hydrogen bus. In addition, a numerical model was developed to predict the change in flow velocity according to the inlet pressure, and an experiment was performed through a model tank to prove the validity of the prediction result. As a result of the experiment, the flow velocity near the tank wall was similar to the predicted value of the analysis model, and when the inlet pressure was 1.5 to 5.5 bar, the minimum size of the removable bubble was predicted to be about 2.2 to 4.6 mm.

• Korean Chemical Engineering Research
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• v.57 no.1
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• pp.28-41
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• 2019

We carried out performance analysis of Sodium-Water Reaction Pressure Relief System of Prototype Generation-IV Sodium-Cooled Fast Reactor. We analyzed transient-dynamic behavior of fluids inside the steam generator to vent into a sodium dump tank or a water dump tank when tubes in the steam generator were broken to cause a large-water-leak accident. Accordingly, we preliminarily evaluated design requirements of our system. Our results showed that sodium in the shell side of the steam generator and in Intermediate Heat Transport System was completely vented within 50 s and feed water in the tube side of the steam generator was completely vented within 2.5 s. It was analyzed that pressure of the tube side of the steam generator was higher than pressure of the shell side of the steam generator, which showed that sodium in the shell side did not flow into the tube side. Our results are expected to be used as basis information to performance analysis of Sodium-Water Reaction Pressure Relief System of Prototype Generation-IV Sodium-Cooled Fast Reactor.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.725-730
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• 2011

A 2-way solenoid valve regulates to maintain the pressure of ullage volume of propellant tanks when the command is given by control system for the liquid-propellant feeding system of space launch vehicle. The simulation model of solenoid valve for pressurization is designed with AMESim to verify the designs and evaluate the dynamic characteristics and pneumatic behaviors of valve. To validate a valve simulation model, the simulation results of their operating durations of valve by AMESim analysis are compared with the results of experiments. Using the model, we analyze performance of valve; opening/closing pressure, operating time on various design factors; shape of control valve seat, basic valve seat, rate of sealing diameter. This study will serve as one of reference guides to enhance the developmental efficiency of ventilation-relief valves with the various operating conditions, which shall be used in Korea Space Launch Vehicle-II.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.2
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• pp.128-134
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• 2013

A 2-way solenoid valve regulates to maintain the pressure of ullage volume of propellant tanks when the command is given by control system for the liquid-propellant feeding system of space launch vehicle. The simulation model of solenoid valve for pressurization is designed with AMESim to verify the designs and evaluate the dynamic characteristics and pneumatic behaviors of valve. To improve the accuracy of the model, numerical flow analysis by using FLUNET code. The simulation results of their operating durations of valve by AMESim analysis are matched up with the results of experiments and validate valve model. Using the model, we analyze performance of valve; opening/closing pressure, operating time on various design factors of basic valve and control valve; geometrical size of valve seat, ratio of basic valve and sealing area.