• Journal of the Korean Institute of Gas
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• v.23 no.4
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• pp.28-39
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• 2019

In this paper is image characteristics of main gas can be a basic data for the identification of the type of leaking gas and the estimation of the emission quantity in OGI(Optical Gas Image) technology. The purpose of this research is to observe the differences of leaking gas images of the two important hydrocarbons of methane and propane in the industry. We fabricated a wind shield of quartz-based with infrared-permeable properties was prepared and methane and propane were simultaneous emission and then photographed with an infrared OGI camera and we are analyzed it. We have a stable image with windbreak of quartz-based minimizes the effect of wind. As a result of analyzing the image of two hydrocarbons with a leakage gas reference value of 1 L/min, an easily recognizable distances by OGI camera were 6 m for methane and 9 m for propane. In the distances range of 1 to 10 m between the infrared camera and the leaking gas point, the gas plume size of the propane gas was larger and clear than that of the methane gas plume. Compared with the number of points in the image, propane was 3.8 times more than methane.

• Journal of the Korean Institute of Gas
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• v.11 no.4
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• pp.47-53
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• 2007

The safe operation of high pressure pipe line systems is of significant importance. Leaks due to faulty operation from the pipelines can lead to considerable product losses and to exposure of community to dangerous gases. There are several leak detection methods, which have been recently suggested on pipeline network. The negative pressure wave detection technology, which has advantages of short time detection availability, accurate leaking location estimate capability and cost effective, is concentrated in this study. Theoretical analysis of the flow characteristics for leaking through a hole on the pipe wall has been performed by using CFD++, commercial CFD package. The results of 3-dimensional analysis near leaking hole confirm the occurrence of negative pressure wave and verify the characteristics of propagation of the wave which travels with speed equal to the speed of sound in the pipeline contents. For the application of long pipe line system. The method of 1-dimensional analysis has been suggested and verified with results of CFD++.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.793-794
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• 2010

• Journal of the Korean Institute of Gas
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• v.21 no.4
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• pp.1-5
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• 2017

Leaking of natural gas, which is mostly methane, in a confined living space creates flammable atmosphere and gives rise to explosion accident. The minimum amount of leaked methane for explosion is highly dependent on the degree of mixing in the confined space. This paper proposes a method for estimating minimum amount of flammable gas for explosion by using Gaussian distribution explosion model(GDEM) and experimental explosion data. The explosion pressure in the confined space can be estimated by assuming the Gaussian distribution of flammable gas along the height of an enclosure and estimating the maximum amount of gas within flammable limits, combustion of the estimated gas with constant volume and adiabatic or isothermal mixing in the confined space. The predicted minimum gas amount for an explosion is tied to explosion pressure that results in a given building damage level. The result shows that very small amount of methane leaking in the confined space may results in a serious gas explosion accident. This result could be applied not only to setting the leak criteria for developing a gas safety appliance but also to accident investigating of explosion.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.705-712
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• 2000

The fluid generally flows through fractures in crystalline rocks where most of underground storage facilities are constructed because of their low hydraulic conductivities. The fractured rock is better to be conceptualized with a discrete fracture concept, rather continuum approach. In the aspect of fluid flow in underground, the simultaneous flow of groundwater and gas should be considered in the cases of generation and leakage of gas in nuclear waste disposal facilities, air sparging process and soil vapor extraction for eliminating contaminants in soil or rock pore, and pneumatic fracturing for the improvement of permeability of rock mass. For the purpose of appropriate analysis of groundwater-gas flow, this study presents an unsteady-state multi-phase FEM fracture network simulator. Numerical simulation has been also conducted to investigate the hydraulic head distribution and air tightness around Ulsan LPG storage cavern. The recorded hydraulic head at the observation well Y was -5 to -10 m. From the results obtained by the developed model, it shows that the discrete fracture model yielded hydraulic head of -10 m, whereas great discrepancy with the field data was observed in the case of equivalent continuum modeling. The air tightness of individual fractures around cavern was examined according to two different operating pressures and as a result, only several numbers of fractures neighboring the cavern did not satisfy the criteria of air tightness at 882 kPa of cavern pressure. In the meantime, when operating pressure is 710.5 kPa, the most areas did not satisfy air tightness criteria. Finally, in the case of gas leaking from cavern to the surrounding rocks, the resulted hydraulic head and flowing pattern was changed and, therefore, gas was leaked out from the cavern ceiling and groundwater was flowed into the cavern through the walls.

• Corrosion Science and Technology
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• v.3 no.6
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• pp.257-261
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• 2004

Leaking of fuel gas in a building creates flammable atmosphere and gives rise to explosion. Observations from accidents suggest that some explosions are caused by quantity of gas significantly less than the lower explosion limit amount required to fill the whole confined space, which might be attributed to inhomogeneous mixing of the leaked gas. The minimum amount of leaked gas for explosion is highly dependent on the degree of mixing in the building. This paper proposes a method for estimating minimum amount of flammable gas for explosion assuming Gaussian distribution of flammable gas.

• Journal of the Korean Institute of Gas
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• v.11 no.4
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• pp.59-63
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• 2007

The purpose of this paper is to find optimum vent port of the booth for gas explosion experiment. Also, it is to understand the safety of the booth for explosion experiment which is installed to let the trainees for legal education which is managed by IGTT(Institute of gas technology training) blow the riskiness of explosion. Since the booth for gas explosion experiment is a confined space, we used the exhaust model for indoor explosion. As the result, it was safety calculated when the amount of leaking gas was close to the maximum of explosion limit on the explosion experiment.

• Journal of the Korean Institute of Gas
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• v.18 no.5
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• pp.1-5
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• 2014

As high-tech science has developed, the need of semiconductor is required constantly. However, there are many processes which use a great deal of poisonous gas in the semiconductor process, so the dangerousness by a gas leak is latent in these processes. Especially, the accident of toxic gas is almost made by ammonia and chlorine. Therefore this report estimates the damage by the leak of ammonia and chlorine used in LPCVD system.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.04a
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• pp.468-475
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• 2001

It can be seen through the previous earthquake damages that indirect damages such as those by fire are much greater rather than direct (firsthand) damage by earthquakes. Recently, gas is used very popularly all over the country but no measures have been taken against hazards (or dangers), for instance, such as fires caused by leaking gas pipes when earthquakes occur. Earthquake-Actuated Automatic Gas Shutoff Devices (Shutoff Device) are used to prevent such disaster in other countries. ChungJung Engineering. Co. is making a sample of a Shutoff Device for the first time in Korea. In this study, a derivation of mathermatical model and the important effects of various variables on the shutoff device are mentioned.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.628-640
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• 2021

To investigate the supercavity geometry and gas flow structure for the supercavities with two closure types under the different flow conditions, an inhomogeneous multiphase model with the SST turbulence model was established, and validated by experimental results. The results show that two distinct regions exist inside the supercavity, which include the downstream flow region along the gas-water interface and the reverse flow region. For the twin-vortex supercavity, the internal gas leaks from the supercavity boundary by two paths: the supercavity surface and the two-vortex tubes. Increasing Froude number leads to more internal gas stripped from the supercavity surface. Two types of gas loss exist for the re-entrant jet supercavity with high Froude number, one type is the steady process of gas loss, and the major gas-leaking path is the supercavity surface rather than supercavity closure region. The other type is the unsteady periodic ejection, and the gas cluster of periodic ejection is merely a small part of the gas stored inside the supercavity.