• Journal of the Korean Institute of Gas
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• v.22 no.2
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• pp.52-58
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• 2018

The flash point is one of the most important properties to characterize fire and explosion hazard of flammable liquid mixture. In this paper, the flash points of ternary liquid mixture, n-nonane+n-decane+n-tridecane system, were measured using Seta flash closed cup tester. The measured values were compared with the calculated values using Raoult's law and multiple regression analysis. The absolute average errors(AAE) of the results calculated by Raoult's law is $0.6^{\circ}C$. The absolute average errors of the results calculated by multiple regression analysis is $0.4^{\circ}C$. As can be seen from AAE, the calculated values based on multiple regresstion analysis were found to be better than those based on Raoult's law.

• Journal of the Korean Institute of Gas
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• v.18 no.4
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• pp.44-50
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• 2014

For the safe handling of aniline, this study was investigated the explosion limits of aniline in the reference data. And the lower flash points, upper flash points and AITs(auto-ignition temperatures) by ignition delay time were experimented. The lower flash point of aniline by using Setaflash and Penski-Martens closed-cup testers were experimented $66^{\circ}C$ and $73^{\circ}C$, respectively. The lower flash point aniline by using Tag and Cleveland open cup testers were experimented $72^{\circ}C$ and $78^{\circ}C$, respectively. Also, this study measured relationship between the AITs and the ignition delay times by using ASTM E659 tester for aniline. The experimental AIT of aniline was $590^{\circ}C$. The calculated LEL and UEL by using the measured low flash point and upper flash point were 1.16 Vol.% and 8.36 Vol.%, respectively.

• Journal of the Korean Institute of Gas
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• v.11 no.4
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• pp.73-78
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• 2007

The lower flash points for the n-pentanol+n-propionic acid and n-pentanol+n-butyric acid systems, in air at atmospheric pressure, were measured by using Pensky-Martens closed cup apparatus. The experimental data were compared with the values calculated by the Raoult's law and optimization method. The calculated values based on the optimization method were found to be better than those based on the Raoult's law.

• Journal of the Korean Institute of Gas
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• v.14 no.5
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• pp.19-25
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• 2010

The flash points for the systems, o-xylene+n-pentanol and m-xylene+n-hexanol, were measured by using Tag open-cup tester(ASTM D1310-86). The experimental data were compared with the values calculated by the Raoult's law and the optimization method using van Laar and Wilson equations. The calculated values based on the optimization method were found to be better than those based on the Raoult's law. The predictive curve of the flash point prediction model based on the van Laar equation described the experimentally-derived data more effectively than was the case when the prediction model was based upon the Wilson equation.

• Journal of the Korean Institute of Gas
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• v.18 no.2
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• pp.35-40
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• 2014

For the safe handling of cyclopentanol, this study was investigated the explosion limits of cyclopentanol in the reference data. The flash points and AITs(auto-ignition temperatures) by ignition delay time were experimented. The lower flash point of cyclopentanol by using closed-cup cyclopentanol was experimented at $49^{\circ}C$. The lower flash points of cyclopentanol by using open cup tester was experimented at $59^{\circ}C$. This study measured relationship between the AITs and the ignition delay times by using ASTM E659 tester for cyclopentanol. The experimental AIT of cyclopentanol was at $363 ^{\circ}C$.

• Journal of the Korean Institute of Gas
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• v.17 no.4
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• pp.70-76
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• 2013

For the safe handling of styrene, this study was investigated the explosion limits of styrene in the reference data. The flash points and AITs(auto-ignition temperatures) by ignition delay time were experimented. As a results, the lower and upper explosion limits of styrene recommended 0.9 Vol.% and 8.0 Vol.%, respectively. The lower flash points of styrene by using closed-cup tester were experimented $29^{\circ}C{\sim}31^{\circ}C$. The lower flash points of styrene by using open cup tester were experimented $32^{\circ}C{\sim}36^{\circ}C$. This study measured relationship between the AITs and the ignition delay times by using ASTM E659 tester for styrene. The experimental AIT of styrene was $460^{\circ}C$.

• Journal of the Korea Safety Management & Science
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• v.8 no.6
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• pp.29-39
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• 2006

The effect of parameters on the consequence of the flash fire accident by the release of heavy gas(in this study, xylene vapor) was analyzed. Simulation results showed that the distance with the lower flammable limit($X_{LFL}$) was increased with the increase of the release hole diameter. For the case of the elevated release, $X_{LFL}$ was increased with the increase of the wind speed and the release height, but $X_{LFL}$ was not affected by the wind speed for the release on the ground level. Therefore, the accident in the elevated release was more dangerous than the release on the ground level. In this condition, the release height had more effect on $X_{LFL}$ at the night time than the daytime and in the urban area than the rural area.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.12
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• pp.984-991
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• 2006

The applications of multi air-conditioners into multiplex and high-rise buildings have been increased by replacing central air-conditioning systems. The pipe length and altitude difference between the indoor and outdoor units can be increased based on installation conditions, which may increase the possibility of flash gas generation at the expansion device inlet. The flash gas generation causes rapid reduction of refrigerant flow rate passing through the expansion device, yielding lower system efficiency. Accumulator heat exchangers have been widely used in multi air-conditioners in order to minimize flash gas generation and obtain system reliability. However, the studies on the heat transfer characteristics and pressure drops of accumulator heat exchangers are very limited in open literature. In this study, the heat transfer rates and pressure drops of accumulator heat exchangers were measured with refrigerant flow rate and operating conditions by using R-22. The heat transfer rate increased with the increase of refrigerant flow rate, while subcooling decreased. The heat transfer rate enhanced with the reduction of inlet superheat and subcooling due to the increased temperature difference between the accumulator and inner heat exchanger.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.6
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• pp.979-985
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• 2011

This paper includes that there are results of designing the flash hider and analyzing fluid dynamics of a front area of the barrel to shorten the length of small arms. Generally, the muzzle flash can be generated out of the barrel by the reaction between the oxygen in the air and unburned gunpowder contained in the propellant gas if a barrel is not long enough to burn gunpowder fully inside of the barrel. Though, the hugh muzzle flash, which is a characteristic of small arms with short barrel length, caused a soldier to aim at the target at night by making the soldier blind for a while and endangers his life by revealing firing position to enemies. Besides, the heat of muzzle flash can weaken the performance of thermal sights, which are attached to small arms for night battlefield. In this paper, flash hiders with several different shapes were designed for a newly developed 5.56mm caliber rifle with short barrel length. The performance of each flash hider to reduce the muzzle flash was compared theoretically and experimentally. Through the authorized test procedure, a highly efficient design of flash hider for reducing the muzzle flash was identified. The result of the paper can be helpful when designing flash hiders for small arms with short barrel length.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.6
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• pp.297-305
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• 2017

Air-source heat pumps are widely used in residential heating systems. However, the decrease in the capacity of the heat pump is unavoidable when operating at very low and high ambient temperatures. The vapor injection technique is considered a promising technology to overcome this problem. Recent research on vapor injection cycles have mainly adopted a scroll compressor with an internal heat exchanger at severe operating conditions. This study measured the COP and EER of a gas injection heat pump using a flash tank with an inverter-driven rotary compressor at severe operating conditions. Compared to non-injection heat pumps, the heating capacity and COP of the gas injection heat pump improved up to 15% and 2.9%, respectively, at outdoor temperatures of $-10^{\circ}C$ to $7^{\circ}C$. The cooling capacity of the gas injection heat pump was 11% higher than the non-injection heat pump at an outdoor temperature of $35^{\circ}C$. At the same time, the EER of the gas injection heat pump was similar to that of the non-injection heat pump.