Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Institute of Gas
Journal Basic Information
Journal DOI :
The Korean Institute of GAS
Editor in Chief :
Volume & Issues
Volume 11, Issue 4 - Dec 2007
Volume 11, Issue 3 - Sep 2007
Volume 11, Issue 2 - Jun 2007
Volume 11, Issue 1 - Mar 2007
Selecting the target year
Heat Transfer Characteristics of Carbon Dioxide in a Inclined Helical Coil Type Heat Exchanger with Inner Diameter Tube of 4.55 mm
Son, Chang-Hyo ;
Journal of the Korean Institute of Gas, volume 11, issue 3, 2007, Pages 1~6
The heat transfer coefficient and pressure drop during gas cooling process of
(R-744) in inclined helical coil copper tubes were investigated experimentally. The main components of the refrigerant loop are a receiver, a variable-speed pump, a mass flow meter, a pre-heater and a inclined helical coil type gas cooler (test section). The test section consists of a smooth copper tube, which is specified as the inner diameter of 4.55 mm. The refrigerant mass fluxes were varied from 200 to
and the inlet pressures of gas cooler were done 7.5 to 10.0 (MPa). The heat transfer coefficients of
in the inclined helical coil tubes increase with the increase of mass flux and gas cooling pressure of
. The pressure drop of
in the gas cooler shows relatively good coincidence with those predicted by Ito's correlation developed for single-phase in a helical coil tube. The local heat transfer coefficient of
is well coincident with the correlation by Pitla et al. However, at the region near pseudo-critical temperature, the experiments indicate higher values than the Pitla et al. correlation.
Fire Extinguishing Ability of Binary Gaseous Extinguishing Agents Evaluated by Cup Burner and Numerical Studies
Kwon, Kyung-Ok ; Won, Dong-Bin ; Choi, Keun-Joo ; Kim, Jong-Won ; Shin, Dong-Il ;
Journal of the Korean Institute of Gas, volume 11, issue 3, 2007, Pages 7~12
The search for a new fire-extinguishing agent with all the desirable properties of halon 1301 has not been successful. To study binary gaseous extinguishing agents instead, one has to determine the extinguishing concentrations for several compositions of a given chemical in an inert gas. This process is expensive and time consuming. The fire suppression efficiencies of gas mixtures of HFC 125 and HFC 227ea with nitrogen as total flooding agents were studied by cup burner method. It was shown that addition of small amounts of those extinguishants to nitrogen can enhance the suppression effectiveness of the inert gas. As expected, the degree of synergism was highest at low concentrations of the chemical. For each binary system, extinguishing concentrations of the pure compounds and one binary data were used to predict the extinguishing concentrations for the entire range of binary composition. The predicted values were very close to experimental data.
Multivariate Statistical Analysis and Prediction for the Flash Points of Binary Systems Using Physical Properties of Pure Substances
Lee, Bom-Sock ; Kim, Sung-Young ;
Journal of the Korean Institute of Gas, volume 11, issue 3, 2007, Pages 13~18
The multivariate statistical analysis, using the multiple linear regression(MLR), have been applied to analyze and predict the flash points of binary systems. Prediction for the flash points of flammable substances is important for the examination of the fire and explosion hazards in the chemical process design. In this paper, the flash points are predicted by MLR based on the physical properties of pure substances and the experimental flash points data. The results of regression and prediction by MLR are compared with the values calculated by Raoult's law and Van Laar equation.
Heat Transfer Analysis of a Coil-Typed LPG Vaporizer with an Electrically Heating Water Bath
Choi, Sung-Joon ; Kwon, Jeong-Rock ; Kim, Kwang-Seok ; Kim, Hyo ;
Journal of the Korean Institute of Gas, volume 11, issue 3, 2007, Pages 19~25
The heat transfer phenomena in a coil-typed LPG vaporizer with a hot water bath employed an electrical heating system were experimentally analyzed. The heat energy is initially used to sensible heat region to heat LPG and then is done to latent heat region to vaporize LPG and to heat up the vaporized gas. A two-phase flow region could be found from periodic temperature fluctuations, and only sensible heat effect was found after passing through the region. The overall heat capacity was defined as multiplying the overall heat transfer coefficient by the heat transfer area and we found a correlation employing the heating water temperature and LPG flow rate. The results of this work can effectively be applied for the design of field scale LPG vaporizers in the near future because they can predict the features of heat transfer on a kind of coil type LPG vaporizer.
Fitness-For-Service of Heat Exchanger Tubing Expansion Transition Zone
Yu, Kwang-Soo ; Choi, Song-Chun ; Kim, Yong-Soo ;
Journal of the Korean Institute of Gas, volume 11, issue 3, 2007, Pages 26~32
The purposes of this study is R/D Tech gratitude TC-5700 system used as an inspection device, purobu uses a representative inner insertion formula coil. Various defects of an installed cylinder thermal exchanger were processed into a regular shape and arrangement tube in the shell inside that was pressure courage. I carried out a test about expanding zone test sample and considered possibility of the defect detection, because a stress corrosion crevice and the same defect cannot forecast a crevice growth speed, cause leakage of a thermal exchanger, and large in quality of a production product can affect it. I was able to evaluate the detection of a circumference direction defect and size of a defect in the tube which did not get expanding zone rolling done comparatively exactly.
Fundamental Study on the Development of the EGR Efficiency (Part I: Effects of Reformer Gas Addition in
Lee, Chang-Eon ; Hwang, Cheol-Hong ; Tak, Young-Jo ;
Journal of the Korean Institute of Gas, volume 11, issue 3, 2007, Pages 33~39
In this study, the effect of reformer gas(RG) on the performance development of the exhaust gas recirculation(EGR) was investigated numerically in
premixed flame. Typically EGR is used to reduce the flame temperature and NOx emission, whereas RG can be used to improve the flame stability, such as homing velocity. This competitive relationship is focused in this study. As a result, it can be identified that the adjustments of EGR and RG ratio can achieve the low NOx emission and the similar flame stability to pure
premixed flame simultaneously.
Characteristics of 5 kW Class Proton-Exchange-Membrane Fuel Cell(PEMFC) Stack according to the Long-Term Operation
Kim, Jae-Dong ; Lee, Jung-Woon ; Park, Dal-Ryung ;
Journal of the Korean Institute of Gas, volume 11, issue 3, 2007, Pages 40~43
The performance of PEMFC stack can be improved significantly by optimizing the design and operating conditions. As a result, the performance of daily operation showed slight deviation (0.02-0.9%) after accumulated DSS operation for 500 hrs but the stack performance was stable. Therefore, it is confirmed that it would be improved the life-time of stack and operation reliability for the commercialization of PEMFC system.
Heat Transfer Characteristics of Supercritical
in Helical Coil Gas Coolers on the Change of Coil Diameters
Son, Chang-Hyo ;
Journal of the Korean Institute of Gas, volume 11, issue 3, 2007, Pages 44~48
The cooling heat transfer characteristics of supercritical
in a helical coil gas cooler on the change of coil diameters are experimentally investigated. The main components of the refrigerant loop are a receiver, a variable speed pump, a mass flow-meter, a pre-heater and a helical coil gas cooler (test section). The test sections are made of a copper tube which the inner diameter is 4.55 mm and the helical coil diameters are done of 26.75 mm and 41.35 mm. The mass fluxes of refrigerant are varied from 200 to 800 [
] and the inlet pressures of gas cooler are 7.5 to 10.0 (MPa). A gas cooler with helical coil diameter of 26.75 mm has larger heat transfer coefficient than that of 41.35 mm. Also, when compared with experimental data and published correlations avaliable, most of correlations are under-predicted, but Pitla published correlations avaliable, most of correlations are under-predicted, but Pitla et al.'s correlation shows a relatively good coincidence with the experimental data except the region of pseudo critical temperature.
Buried Polyethylene Gas Pipes Analysis using Finite Element Method under External Loadings
Kil, Seong-Hee ; Jo, Do-Young ;
Journal of the Korean Institute of Gas, volume 11, issue 3, 2007, Pages 49~55
Polyethylene pipes have been widely used as they are easy to construct and suitable for economical efficient when they are compared with metal pipelines. This paper studies the effect of various external loadings on stress and deflection of the buried PE pipes using Finite Element Method(FEM). For this purpose, stresses of buried PE pipes are calculated according to the loading condition such as pipe types (pipe diameter
), burial depths (
) and internal pressures (
). As a result, it is founded the effect and relation with each of loading conditions under the buried condition.
A Study on Management Applications Using 6 Sigma Techniques to Supply Equipment Maintenance of City Gas
Kim, Woon-Tae ;
Journal of the Korean Institute of Gas, volume 11, issue 3, 2007, Pages 56~63
These days, needs and wants of the customers are getting diversified and the market is also changing rapidely. Many organizations are now attempting change and innovation activities to improve products and service quality. This study was performed to apply 6 sigma tools for the efficient repair management of city gas supply equipment. Vital few factors, RISK factors, sigma values, root causes. and solutions were derived by 6 sigma tools. We are performing statistical process control for the new process. Six sigma for city gas supply equipment safety management enabled to improve the business management for efficiency by reducing variation and eliminating cost for quality.