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 16, Issue 6 - Dec 2012
Volume 16, Issue 5 - Oct 2012
Volume 16, Issue 4 - Aug 2012
Volume 16, Issue 3 - Jun 2012
Volume 16, Issue 2 - Apr 2012
Volume 16, Issue 1 - Feb 2012
Selecting the target year
Characteristics of Flow Uniformity at the Section before Tube Bank with the Change of Expansion Inlet Duct Shape in a Heat Recovery Steam Generator
Ha, Ji-Soo ;
Journal of the Korean Institute of Gas, volume 16, issue 1, 2012, Pages 1~7
DOI : 10.7842/kigas.2012.16.1.1
The present study has been carried out to analyze the flow characteristics in the inlet expasion duct of a heat recovery steam generator by using numerical flow analysis. The inlet of HRSG corresponds the outlet of gas turbine exit and the flow after gas turbine has strong swirl flow and turbulence. The inlet flow condition of HRSG should be included the exit flow characteristics of gas turbine. The present numerical analysis adopted the flow analysis result of gas turbine exit flow as a inlet flow condition of HRSG analysis. Because the flow characteristics in the inlet duct of the tube bank is strongly related to the performance of a HRSG, it is most important for the optimal design of HGSG to understanding the flow phenomena in the inlet duct of HRSG. From the present study, the position of breakpoint in the inlet expansion duct should be lower than the reference breakpoint position for the optimal flow uniformity before the tube bank.
A Study on Physicochemical Characteristics of Hydrogen Gas Explosion
Jo, Young-Do ;
Journal of the Korean Institute of Gas, volume 16, issue 1, 2012, Pages 8~14
DOI : 10.7842/kigas.2012.16.1.8
Hydrogen is considered to be the most important future energy carrier in many applications reducing significantly greenhouse gas emissions, but the explosion safety issues associated with hydrogen applications need to be investigated and fully understood to be applicable as the carrier. The risk associated with a explosion depends on an understanding of the impacts of the explosion, particularly the pressure-time history during the explosion. This work provides the effects of explosion parameters, such as specific heat ratio of burned and unburned gas, equilibrium maximum explosion pressure, and burning velocity, on the pressure-time history with flame growth model. The pressure-time history is dominantly depending on the burning velocity and equilibrium maximum explosion pressure of hydrogen-air mixture. The pressure rise rate increase with the burning velocity and equilibrium maximum explosion pressure. The specific heat ratio of unburned gas has more effect on the final explosion pressure increase rate than initial explosion pressure increase rate. However, the specific heat ratio of burned gas has more influence on initial explosion pressure increase rate. The flame speeds are obtained by fitting the experimental data sets. The flame speeds for hydrogen in air based on our experimental data is very low, making a transition from deflagration to detonation in a confined space unlikely under these conditions.
Hazard Distance from Hydrogen Accidents
Jo, Young-Do ;
Journal of the Korean Institute of Gas, volume 16, issue 1, 2012, Pages 15~21
DOI : 10.7842/kigas.2012.16.1.15
An analysis was completed of the hazards distance of hydrogen accidents such as jet release, jet fire, and vapor cloud explosion(VCE) of hydrogen gas, and simplified equations have been proposed to predict the hazard distances to set up safety distance by the gas dispersion, fire, and explosion following hydrogen gas release. For a small release rate of hydrogen gas, such as from a pine-hole, the hazard distance from jet dispersion is longer than that from jet fire. The hazard distance is directly proportional to the pressure raised to a half power and to the diameter of hole and up to several tens meters. For a large release rate, such as from full bore rupture of a pipeline or a large hole of storage vessel, the hazard distance from a large jet fire is longer than that from unconfined vapor cloud explosion. The hazard distance from the fire may be up to several hundred meters. Hydrogen filling station in urban area is difficult to compliance with the safety distance criterion, if the accident scenario of large hydrogen gas release is basis for setting up the safety distance, which is minimum separation distance between the station and building. Therefore, the accident of large hydrogen gas release must be prevented by using safety devices and the safety distance may be set based on the small release rate of hydrogen gas. But if there are any possibility of large release, populated building, such as school, hospital etc, should be separated several hundred meters.
Field Inspection of Phase-Array Ultrasonic for PolyEthylene Electrofusion Joints
Kil, Seong-Hee ; Jo, Young-Do ; Yoon, Kee-Bong ;
Journal of the Korean Institute of Gas, volume 16, issue 1, 2012, Pages 22~25
DOI : 10.7842/kigas.2012.16.1.22
Welding and/or fusion in polyethylene(PE) system made on site is focused on the control of the welding or fusion process to follow proper procedure. The process control is important, but it is not sufficient for the long term reliability of a pipe system. To achieve the rate of failure close to zero, Non Destructive Testing(NDT) is necessary in addition to joining process control. For electrofusion joints several non-destructive testing methods are available. The ultrasonic phased array technique is possible to detect various defects including wire deviations and regions with lack of fusion. In this studies, testing was carried to detect the defect after electrofusion joining of polyethylene piping is utilized by the ultrasonic phased array technique. From testing data, ultrasonic phased array technique is recommended as a reliable non-destructive testing method.
Comparison of Partial Least Squares and Support Vector Machine for the Autoignition Temperature Prediction of Organic Compounds
Lee, Gi-Baek ;
Journal of the Korean Institute of Gas, volume 16, issue 1, 2012, Pages 26~32
DOI : 10.7842/kigas.2012.16.1.26
The autoignition temperature is one of the most important physical properties used to determine the flammability characteristics of chemical substances. Despite the needs of the experimental autoignition temperature data for the design of chemical plants, it is not easy to get the data. This study have built and compared partial least squares (PLS) and support vector machine (SVM) models to predict the autoignition temperatures of 503 organic compounds out of DIPPR 801. As the independent variables of the models, 59 functional groups were chosen based on the group contribution method. The prediction errors calculated from cross-validation were employed to determine the optimal parameters of two models. And, particle swarm optimization was used to get three parameters of SVM model. The PLS and SVM results of the average absolute errors for the whole data range from 58.59K and 29.11K, respectively, indicating that the predictive ability of the SVM is much superior than PLS.
Data Mining of Gas Accident and Meteorological Data in Korea for a Prediction Model of Gas Accidents
Hur, Young-Taeg ; Shin, Dong-Il ; Lee, Su-Kyung ;
Journal of the Korean Institute of Gas, volume 16, issue 1, 2012, Pages 33~38
DOI : 10.7842/kigas.2012.16.1.33
Analysis on gas accidents by types occurred has been made to prevent the recurrence of accidents, through analysis of past history of gas accident occurring environment. The number of gas accidents has been decreasing, but still accidents are occurring steadily. Gas-using environment and gas accidents are estimated to be closely connected since gas-using types are changing by time period, weather, etc. in terms of accident contents. As a result of analysing gas accidents by 7 meteorological elements, such as the mean temperature, the highest temperature, the lowest temperature, relative humidity, the amount of clouds, precipitation and wind velocity, it has been found out that gas accidents are influenced by temperature or relative humidity, and accident occurs more frequently when the sky is clean and wind velocity is slow. Possibility of gas accidents can be provided in real time, using the proposed model made to predict gas accidents in connection with the weather forecast service. Possibility and number of gas accidents will be checked real time by connecting to the business system of Korea Gas Safety Corp., and it is considered that it would be positively used for preventing gas accidents.
A Development of System for Efficient Quantitative Risk Assessment on Natural Gas Supply Facilities
Yoon, Ik-Keun ; Oh, Shin-Kyu ; Seo, Jae-Min ; Lim, Dong-Yeon ; Yoon, En-Sup ;
Journal of the Korean Institute of Gas, volume 16, issue 1, 2012, Pages 39~45
DOI : 10.7842/kigas.2012.16.1.39
While the natural gas supply industry has continuously been growing, its potential hazard has also risen since the natural gas facilities essentially require installations that carry highly flammable and pressurized gas close to the populated areas, posing a serious consequence of significant property damage as well as human casualties in the event of accident. Therefore Quantitative Risk Assessment (QAR) has been recognized as a appropriate method to reduce the risk as far as possible, considering the reality of unachievable zero-risk. However, it is hard to perform effective QRA on hundreds of gas facilities because of insufficient number of expert and long-term analysis. In this paper, we suggest a conceptual QRA system framework to support more efficient risk analysis in gas supply facilities. In this system, the experts make questionnaires and internal calculation formula needed in accident frequency/consequence analysis of the facility through pre-analysis on the point of analysis, called incident point, and general users locate the point on the map and input the value required by the questionnaire to obtain the risk. Ultimately, this is suggested based on the idea that the specialization is available in QRA analysis process and the validity of the system is verified through actual system construction and application.
A Study on the Behavior of Ambient Hydraulic Cycling Test for 70 MPa Type3 Hydrogen Composite Cylinder
Cho, Sung-Min ; Kim, Chang-Jong ; Kim, Young-Gyu ;
Journal of the Korean Institute of Gas, volume 16, issue 1, 2012, Pages 46~50
DOI : 10.7842/kigas.2012.16.1.46
The performance of the Type3 hydrogen composite cylinder whose pressure is 70 MPa using hydrostatic cycling test equipment was evaluted in this study. It also includes the finite element method analysis on the performance of the cylinder when the pressure is applied. As a result, cylinder body parts of the Type3 hydrogen composite cylinder, which draws attention with its safe status and the lightness, was ruptured first and the same result has been found out through the finite element method. The dome knuckle and the cylinder body were proved as the weakest parts since the cylinder body parts was expanded under the pressure.