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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Institute of Gas
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Journal DOI :
The Korean Institute of GAS
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Volume & Issues
Volume 12, Issue 4 - Dec 2008
Volume 12, Issue 3 - Sep 2008
Volume 12, Issue 2 - Jun 2008
Volume 12, Issue 1 - Mar 2008
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Dynamic Fracture Properties of Nylon Thermoplastic Material Depending on Notch Angle with Charpy Impact Machine and Finite Element Method
Park, Myung-Kyun ; Lee, Jung-Won ; Kim, Tae-Ok ;
Journal of the Korean Institute of Gas, volume 12, issue 1, 2008, Pages 1~6
The notched Charpy impact test is one of the most prevalent techniques used to characterize the effect of high impulse loads on polymeric materials. In this study, a method of analysis in nylon plastic materials is suggested to evaluate the critical strain energy release rate for variation of notch angles from the Charpy impact energy measurement. Instrumented Charpy impact tester was used to extract ancillary information concerning fracture parameters in addition to total fracture properties and maximum critical load. The dynamic stress intensity factor of nylon plastic material was calculated for the ASTM Charpy specimen from the obtained maximum critical load. Also, the finite element model was developed to figure out the stress distributions for Charpy specimen with different notch angles subject to 3 point bending load which is equivalent to the load applied in the experiment.
Stress Distribution of Buried Gas Transportation Pipeline According to Vehicle Load Velocity
Won, Jong-Hwa ; Kim, Moon-Kyum ; Yoo, Han-Kyu ; Kim, Mi-Seoung ;
Journal of the Korean Institute of Gas, volume 12, issue 1, 2008, Pages 7~12
In order to estimate the integrity and identify the dynamic characteristics of buried gas pipelines subjected to vehicle loads, FE analysis is performed based on the 'Highway and Local Road Design Criteria' and the 'KOGAS Guideline for Pipeline Management'. The FE model describes the current burial condition of Korea properly, and the DB-24 load model is adopted for this research. This study considers a varying velocity in the range of
MPa(internal pressure) with depth cover, Z=1.5 m. Maximum stress occurs at v=80 km/h and decreases after v=80 km/h. The maximum induced stress by DB-24 loads is about 10 MPa. Under the design pressure, however, the analysis results show that API 5L Gr. X65 pipelines have sufficient integrity to withstand the vibration of vehicle loads.
Dynamic Characteristics of Buried Pipeline under Vibration Velocity of Vehicle Loads
Won, Jong-Hwa ; Sun, Jin-Sun ; Yoo, Han-Kyu ; Kim, Moon-Kyum ;
Journal of the Korean Institute of Gas, volume 12, issue 1, 2008, Pages 13~18
Vibration velocity induced by earthquakes or external vibration sources is one of the integrity assessment indexes, and is also a representative value used to describe the amount of vibration because it is based on a proportional relationship with the damage scale. In this study, the vibration velocity criterion for structures is first examined. Then, based on the velocity criterion, an integrity assessment is performed. Burial condition is set up based on the "Highway and Local Road Design Criteria" with API 5L Gr. X65 pipeline(D=762 mm). The FE model considers DB-24 vehicle load as a time function with a varying velocity in the range of
. Maximum vibration velocity occurs at v=80 km/h and decreases after v=80 km/h. The maximum vibration velocity of buried pipeline by DB-24 loads is about 0.034 cm/s. The velocity that occurs is in the range of allowable values for each vibration velocity criterion. The wave propagation velocity was identified based on attenuation law and the minimum value appears at vehicle velocity 80 km/h that has maximum vibration velocity.
Cathodic Protection of Buried Gas Pipelines Using Common Anode Beds
Ha, Y.C. ; Kim, D.K. ; Bae, J.H. ; Ha, T.H. ; Lee, H.G. ;
Journal of the Korean Institute of Gas, volume 12, issue 1, 2008, Pages 19~24
Due to industrialization and urbanization, underground metallic utilities with different owners have been rapidly increased and cathodic protection (CP) methods, especially impressed current CP systems, have been widely adopted to protect their utilities from corrosion with expanded recognition of this method. The stray current interference problem as well as the difficulty in spatial security for system installation, however, came to a ramification of which each owner couldn't resolve for himself. In this respect, this paper illustrates a field-diagnosed example for mutual interference due to separately operated CP systems and suggests an alternative method to overcome the interference situation by design and field-assessment of a common anode bed cathodic protection system.
Development of an Inert Gas Water Mist System -A Numerical Study on Ventilation of the Fire Test Room-
Park, Woe-Chul ; Jeong, Lee-Gyu ;
Journal of the Korean Institute of Gas, volume 12, issue 1, 2008, Pages 25~30
A Numerical study was carried out for a propane gas pool fire in the fire test room of
for testing a inert gas water mist system, to investigate a possible under-ventilation in the fire test room. For the fire sizes of 60 kW and 120 kW, changes in the temperature and CO concentration with and without a window were investigated. It was confirmed that the influence of the window on the distributions of temperature and CO concentration was small in the two fire sizes, and hence the under-ventilation was not occurred in the room.
Study on Adiabatic Performance of LNG Storage Tank for Vehicles
Han, Jeong-Ok ; Lee, Young-Won ;
Journal of the Korean Institute of Gas, volume 12, issue 1, 2008, Pages 31~35
Natural gas vehicles are being applied to city buses for improving air quality in metropolitan and have proved the effective way to reduce the pollutant emissions. Liquified Natural Gas(LNG) has also attempted a vehicle fuel in order to raise the fuel storage density that is a disadvantage of Compressed Natural Gas(CNG). This paper described insulation characteristic of a LNG storage tank. From the results, adiabatic coefficient of a tested tank was around
and it was the lower level than gas safety regulation limit. Two experimental methods were adopted to justify the evaluation results and they were revealed that the results were very similar to each other. Also, through testing relief valve operation characteristic it was investigated venting amount of boiled off gas.
A Study on the Strength Safety Analysis of a Full Containment LNG Storage Tank Due to a Wind Pressure
Kim, Chung-Kyun ; Jeong, Nam-In ;
Journal of the Korean Institute of Gas, volume 12, issue 1, 2008, Pages 36~41
Using the finite element analysis, this paper presents the strength safety of a side wall of an outer tank and a roof structures in a full containment LNG storage tank system. The outer tank structure in which is constructed with a prestressed concrete is forced by internal hydrostatic and hydrodynamic pressures of a leaked LNG and an external wind pressure including a typhoon one. The FEM computed results show that the ring beam between a side wall of an outer tank and a roof structure supports most of the internal and the external loads. This means that the design point of the outer tank system is a ring beam structure and the other one is a center part of the roof structure. In this FE analysis model of a full containment LNG tank system, the outer tank and the roof structures are safe for the given combined loads such as an internal leaked LNG pressure and an external typhoon pressure.
A Study on Estimation of Human Damage for Overpressure by Vapor Cloud Explosion in Enclosure Using Probit Model
Leem, Sa-Hwan ; Lee, Jong-Rark ; Huh, Yong-Jeong ;
Journal of the Korean Institute of Gas, volume 12, issue 1, 2008, Pages 42~47
The demand of gas as an eco-friendly energy source has being increased. With the demand of gas, the use of gas is also increased, so injury and loss of life by the explosion and fire have been increasing every year. Hence the influence on over-pressure caused by Vapor Cloud Explosion in enclosure of experimental booth was calculated by using the Hopkinson's scaling law and damage effect by the accident to a human body was estimated by applying the probit model. As a result of the damage estimation conducted by using the probit model, both the damage possibility of explosion overpressure to human over 3 meters away and that of overpressure to tympanum rupture over 25 meters away from the explosion shows nothing.
The Condensation Heat Transfer of R-22 and R-410A in an Inner Diameter Tube of 1.77 mm
Son, Chang-Hyo ; Roh, Geon-Sang ;
Journal of the Korean Institute of Gas, volume 12, issue 1, 2008, Pages 48~53
The condensation heat transfer coefficients of R-22 and R-410A in a small diameter tube were investigated. The main components of the refrigerant loop consist of a receiver, a variable-speed pump, a mass flowmeter, an evaporator (preheater), and a condenser (test section). The test section consists of smooth, horizontal copper tube of 3.38 mm outer diameter and 1.77 mm inner diameter. The refrigerant mass fluxes varied from 450 to
and the average inlet and outlet qualities were 0.05 and 0.95. The main results were summarized as follows : the condensation heat transfer coefficient also increases with increasing mass flux and quality. The condensation heat transfer coefficient of R-410A was slightly higher than that of R-22. Most of correlations proposed in the large diameter tube showed significant deviations with experimental data except for the ranges of low quality and low mass flux.
Experimental Studies on the Interaction Between a Propagating Flame and Multiple Obstacles in a Rectangular Chamber
Park, Dal-Jae ; Ahn, Jeong-Jin ; Lee, Young-Soon ;
Journal of the Korean Institute of Gas, volume 12, issue 1, 2008, Pages 54~61
Experimental investigations were performed to assess the influences of different multiple obstacles on flame propagation in a rectangular confinement. Three different multiple obstacles were used: circular, triangular and square cross-sections with blockage ratios of 15% and 30%. The same method described in Park et al.  to investigate the interaction between the propagating flame and the obstacle was applied. Before the freely propagating flame impinged on the obstacle, the flame propagation speed remains close to the laminar burning velocity, regardless of the obstacles used. The reported data revealed that the trend in increase of the local flame propagation speed is a result of the interaction between the obstacle and the propagating flame front behind the obstacle. The local speed was found to increase from a circular to a triangular and a square obstacle. The mean flame speed was found to be less dependent on both the obstacle types and the different blockage ratios used.