• Journal of the Korea Convergence Society
• /
• v.9 no.4
• /
• pp.143-150
• /
• 2018

This work conducted the experimental analysis on ultrasonic acoustic matching in order to measure the accuracy of gaseous fuel level values. The experimental devices were used as 12V-DC supply, control T1 board, oscilloscope (DS01072B), ultrasonic probe and pattern table. The research models were designed by ceramic assay which can determine the transmitting and receiving energies. The result of the ringing area could verify the increased characteristics in the order of D (0.180m) < E (0.184m) < B (0.204m) < A (0.234m) < F (0.244m) < C (0.247m) models based on initial 2.9V of the maximum peak voltage. From the experimental results, the model designed by Ø21*3+2t of the matching layer was notable in that the most outstanding directivity energy could be created.

• Journal of the Korean Chemical Society
• /
• v.43 no.5
• /
• pp.517-521
• /
• 1999

Gas chromatography using sulfur chemiluminescence detection (GC-SCD) which exhibits very good selectivity, linearity, and sensitivity was applied to the analysis of suIfur compounds in gaseous fuel. The expectmental method used in this study was to resolve the problems of repeatability and reproducibility by means of the adsorption of sulfur compounds, which is different from the existing analysis method of these compounds by GC-SCD. The calibration curves of the standard gases including dimethyl sulfide, t-butylmercaptan and ethyl methyl sulfide exhibited an excellent linearity. As the result of precision tests for the above three compounds, the high reproducibility for tests showed while repeating three times during four days, respectively. In addition, the coefficient of variation was less than 3%. In consequence, the expectmental method of this study is very effective not only with low uncertainty but also with better accuracy, which can quickly determine the concentration of gas odorants in LPG (Liquefied Petroleum Gas) from oil reservoirs and filling stations.

• Journal of Korean Institute of Fire Investigation
• /
• v.11 no.1
• /
• pp.1-8
• /
• 2008

The purpose of this paper is to report gas fire accident based on classification of the major gas fire causes (including handling mistakes, inferior goods, etc.), fire classifications (fire, explosion, leakages, etc.), damage levels(1st, 2nd, 3rd, 4th grade levels), casualties (death, serious wound, slight injury) since gas fire has been generated according to growth of gaseous fuel consumption on home and enterprises with various accident causes. Among gaseous fuels, LPG facility can be c1assified as gas container, pressure regulator, gas hose, interim valve, combustion port. Any fire or any explosion can be caused from handling mistakes, inferior goods on each parts as stated above. Exact gas fire causes shall be identified based on previous case studies on similar fires with consideration of lesson learns.

• Journal of ILASS-Korea
• /
• v.19 no.3
• /
• pp.142-148
• /
• 2014

In this study, characteristics of gaseous pollutants and particulate matter were investigated on the condition of DPF regeneration and normal DPF condition. THC, CO, $CO_2$, NOx, and $CH_4$ were analyzed by MEXA-7200H and CVS-7100 respectively. Particulate Matter (PM) was measured by difference in weight of Membrane filter. Particle Number (PN) was measured by CPC analyzer. And Sulfate, Nitrate, Organic were measured by Aerosol Mass Spectrometer (AMS). As a result, gaseous pollutants and particulate matter were detected in higher concentration during DPF regeneration than normal DPF condition. And the PN increased by 94%, the fuel consumption was reduced by 29% on DPF generation process. Sulfate, Nitrate and Organic were undetectable level during normal DPF condition. But the highest concentration of Sulfate, Nitrate and Organic were measured as $100{\mu}g/m^3$, $20{\mu}g/m^3$ and $15{\mu}g/m^3$ respectively on DPF regeneration condition. VOCs concentrations (Benzene, Toluene, Ethylbenzene, Xylene) were analyzed by using PTR-MS. Benzene and Toluene emission have little or no change depending on DPF regeneration. But the Ethylbenzene and Xylene have comparatively low emissions on DPF regeneration.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.03a
• /
• pp.804-809
• /
• 2008

In this study, the cooling performance of a C/C composite material structure with metallic cooling tubes fixed by elastic force without chemical bonding was evaluated experimentally using combustion gas in a rocket combustor. The C/C composite chamber was covered by a stainless steel outer shell to maintain its airtightness. Gaseous hydrogen as a fuel and gaseous oxygen as an oxidizer were used for the heating test. The surface of these C/C composites was maintained below 1500 K when the combustion gas temperature was about 2900 K and heat flux to the combustion chamber wall was about 9 $MW/m^2$. No thermal damage was observed on the stainless steel tubes which were in contact with the C/C composite materials. Results of the heating test showed that such a metallic-tube-cooled C/C composite structure is able to control the surface temperature as a cooling structure(also as a heat exchanger), as well as indicating the possibility of reducing the amount of the coolant even if the thermal load to the engine is high. Thus, application of the metallic-tube-cooled C/C composite structure to reusable engines such as a rocket-ramjet combined cycle engine is expected.

• Journal of Soil and Groundwater Environment
• /
• v.22 no.4
• /
• pp.49-59
• /
• 2017

This study estimated the nitrogen budget, including gaseous nitrogen oxides ($NO_x$), of South Korea in 2012~2014. The nitrogen budget was classified into three categories: agricultural and livestock, forest, and city. To estimate the nitrogen budget, several input and output parameters were investigated, including deposition, fixation, irrigation, chemical fertilizer use, compost, fuel, denitrification, volatilization, runoff, crop uptake, leaching, and $NO_x$ emissions. The annual nitrogen inputs from 2012 to 2014 were 6,202,828, 6,137,708, and 6,022,379 ton/yr, respectively. The corresponding annual nitrogen outputs were 1,393,763, 1,380,406, and 1,360,819 ton/yr, respectively, signifying a slight decrease from 2012 to 2014. $NO_x$ was the parameter contributing to the nitrogen budget to the greatest extent. The annual ratios of $NO_x$ emissions by vehicles, power plants, and businesses were 0.31, 0.31, and 0.30 in 2012, 2013, and 2014, respectively. A change in government policy that prohibited the disposal of livestock manure and sewage sludge in the ocean from 2012 affected nitrogen budget profile. As a result, the ocean disposal ratio completely diminished, which differs from previous studies.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.22 no.6
• /
• pp.28-36
• /
• 2018

A study was conducted to apply open-loop control to the combustion instability in a dump combustor using gaseous hydrocarbon fuels. Control power and frequency were varied by employing a loudspeaker under combustion conditions with similar characteristic chemistry times of the fuels. In the case of open-loop control where the frequency was identical to the combustion instability frequency, the open-loop control power affected the control performance. Results obtained from conducted open-loop control tests, where the frequency was different from the combustion instability frequency, show that setting the open-loop control frequency similar to the combustion instability frequency is effective.

• Journal of Korean Society for Atmospheric Environment
• /
• v.26 no.1
• /
• pp.69-76
• /
• 2010

While increased use of motor cycles in the recent years for various demands could worsen air quality, only few studies have been conducted on estimation of emission factors and characterization of emissions from motorcycle. In this study, emissions from selected six models of motorcycle based on largest market share and production rate were investigated. To investigate gaseous and carbonaceous air pollutants, such as carbon monoxide (CO), total hydrocarbon (THC), nitrogen oxide ($NO_x$), elemental carbon (EC) and organic carbon (OC), total 124 motorcycles between 2003 and 2007 model year were tested with regulatory driving conditions, such as CVS-40 and CVS-47 mode. These motorcycles were further sub-categorized based on their displacement (< 50 cc, 50~150 cc, and $\geq$ 150 cc), type of stroke (2- and 4 strokes) and model year (2003~2005 and 2006~2007). Tested motorcycles with recent model year (2006~2007) exhibited less emissions of regulatory gaseous and carbonaceous air pollutants compared to old model year (2003~2005). Chemical analysis showed that CO present in highest concentration followed by THC and $NO_x$ for all tested motorcycles. Interestingly, two strokes motorcycle produced higher THC emission but less CO and $NO_x$ than those of four strokes. For all types of displacement and stroke, emission factors (gram per kilometer) of THC and CO except $NO_x$ with recent model year (2006~2007) showed decreased trend compared to old model year (2003~2005). In addition to this, due to mixed combustion between gasoline fuel and lubricant, two strokes motorcycle showed OC > EC emission trend.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.15 no.2
• /
• pp.68-73
• /
• 2011

For the launch preparation of KSLV-I, gaseous nitrogen with various level of pressure and cryogenic liquid nitrogen are required. Nitrogen Supply System on launch complex has been developed to perform the production of high pressure gaseous nitrogen, the production of gaseous nitrogen with temperature of 273 ${\pm}$ 2K for protection purge of launch vehicle after loading of propellant and the supply of cryogenic liquid nitrogen for cooling of fuel (kerosene) and oxidizer (liquid oxygen). The operational instability of vaporizer mainly caused by its heat transfer characteristics which sensitively depends on the atmospheric conditions was removed by introducing parallel installation of two vaporizer and their switching operation. The developed Nitrogen Supply System carried out its function successfully in preparation of KSLV-I flight tests.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.11a
• /
• pp.752-757
• /
• 2010

For the launch preparation of KSLV-I, gaseous nitrogen with various level of pressure and cryogenic liquid nitrogen are required. Nitrogen Supply System on launch complex has been developed to perform the production of high pressure gaseous nitrogen, the production of gaseous nitrogen with temperature of $273{\pm}2K$ for protection purge of launch vehicle after loading of propellant and the supply of cryogenic liquid nitrogen for cooling of fuel (kerosene) and oxidizer (liquid oxygen). The operational instability of vaporizer mainly caused by its heat transfer characteristics which sensitively depends on the atmospheric conditions was removed by introducing parallel installation of two vaporizer and their switching operation. The developed Nitrogen Supply System carried out its function successfully in preparation of KSLV-I flight tests.