• Journal of Preventive Medicine and Public Health
• /
• v.7 no.2
• /
• pp.373-375
• /
• 1974

The concentration of Carton momoxide(CO) and Sulful dioxide($SO_2$) by burning time of coal, and its time of fading out in atmosphere after effluence from stove were measured with Kitagawa gas detector, January, 1974. Gas for measurement was sampled by gas syringe at the point distanced 60cm. from first junction of garvanized pipe of stove. CO concentration was directly proportional to the burning temperature of coal but $SO_2$ was generally constant durning burning time or also in proportion to burning temperature. CO gas of effluent mixed with air(relative humidity, 40%) was maintained for long period relatively, but $SO_2$ gas was early faded out within short time. The period decreasing to allowable limit was about 4 days in former and about 30 minutes in later, respectiively.

• Journal of the Korean Society of Combustion
• /
• v.13 no.3
• /
• pp.9-16
• /
• 2008

In this study, a cylindrical constant volume combustion chamber is used to investigate the flow and combustion characteristics of methane-air homogeneous mixture under various initial charge pressure, excess air ratios and ignition times. The flame and burning speed, mean gas speed are calculated by numerical analysis to analyze the combustion characteristics. It is found that the mean gas velocity during combustion has the maximum value around 300 ms and then decreased gradually on the condition of 10000 ms, and that the combustion duration is shorten and flame speed and burning velocity have the highest value under the conditions of an excess air ratio 1.1, an initial charge pressure of 0.2 MPa and an ignition time of 300 ms in the present study. And, the initial pressure and burning speed are in inverse proportion, so that it is in agreement with Strehlow who presented that the initial pressure and burning speed are in inverse proportion when the burning speed is under 50cm/s.

• Fire Science and Engineering
• /
• v.10 no.1
• /
• pp.44-48
• /
• 1996

Burning rate of immobilized methyl and ethyl alcohols on ceramic balls was studied. Experiments were performed by burning methyl, ethyl alcohols immobilized on sands (particle size 0.35mm) and ceramic balls (particle size 1-5mm) to measure mass burning rate, height burning rate and combustion temperature. The longer time from ignition to extinguishment was resulted from the larger particle size of ceramic balls and the smaller size of ceramic balls exhibited the higher mass burning rate. Of alcohols tested the relative magnitude of facilitation of combustion was methyl ＞ ethyl. Combustion temperature of alcohols, without regard to the types of alcohols, was not increased with smaller ceramic balls(up to 3mm of particle size). However, with larger ceramic balls, combustion temperatare of alcohols was increased by 40-50$^{\circ}$ and the highest combustion temperatare was obtained with sands (particle size 0.35mm).

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.05a
• /
• pp.169-172
• /
• 2009

In this study, the current researches and the developing trend of the high burning rate solid propellants were briefly introduced and the effects of burning rate modifiers in the propellants on the combustion properties were reviewed. At the same time, bis(ethylenediamine)copper perchlorate(BECP) has been prepared as a burning rate modifier, and the burning characteristics were investigated in Butacene/AP propellants. The results showed that the metal complex, BECP, can increase remarkably the burning rate of high burning rate Butacene/AP propellants.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.20 no.1
• /
• pp.244-254
• /
• 1996

Flow velocity was measured by, use of hot wire anemometer. Turbulence intensity was in proportion to mean flow velocity regardless of swirl velocity. And integral length scale has proportional relation with swirl velocity regardless of measurement position. Turbulent burning speed during flame propagation which was determined by flame photograph and gas pressure of combustion chamber was increased with the lapse of time from spark and was decreased a little at later combustion period. Because of combustion promotion effect, turbulent burning speed was increased according to increase of turbulence intensity. Burning speed ratio i.e. ratio of turbulent burning speed ($S_BT$) to laminar burning speed ($S_BL$) was found out by use of turbulence intensity u' and integral length scale $l_x$ , $\delta_L$ is width of preheat zone in laminar flame.

• Journal of Korean Society for Atmospheric Environment
• /
• v.32 no.2
• /
• pp.167-175
• /
• 2016

In this study, we estimate air pollutants emission from agricultural waste burning. We investigated activities related to agricultural waste burning such as crop burning rates, location, and time by region. The average crop burning rates per square meter farmland of fruits, pulses, barleys, cereals, vegetables, and special crops were $273.1g/m^2$, $105.7g/m^2$, $7.4g/m^2$, $121.0g/m^2$, $290.7g/m^2$, and $392.9g/m^2$, respectively. We estimated air pollutants emissions with pre-developed emission factors. The estimated air pollutant emission of agricultural biomass burning were CO 148,028 ton/year, $NO_x$ 5,220 ton/year, $SO_x$ 11 ton/year, VOC 59,767 ton/year, TSP 21,548 ton/year, $PM_{10}$ 8,909 ton/year, $PM_{2.5}$ 7,405 ton/year, and $NH_3$ 5 ton/year. When these results compared with the entire emissions of national inventory (CAPSS), CO, VOC, $PM_{10}$ account for about 17.8%, 6.2%, 6.7% of the total, respectively.

• Journal of the Korean institute of surface engineering
• /
• v.53 no.1
• /
• pp.15-21
• /
• 2020

In this study, growth and burning behavior of 6061 aluminum alloy was studied under constant anodic voltages at various temperatures and magnetic stirring rates in 20% sulfuric acid solution by analysing I-t curves, measuring thickness and hardness of aluminum anodic oxide (AAO) films, observations of surface and cross-sectional images of AAO films. AAO films were grown continuously at lower voltages than 18.5V but burning occurred when a voltage more than 19V was applied in 20% H₂SO₄ solution at 20±0.5℃ and 200 rpm of magnetic stirring. The burning was always related with an extremely large increase of anodic current density with anodizing time, suggesting that high heat generation during anodizing causes deteriorations of AAO films by chemical reaction with acidic solutions. The burning resulted in decreases of film thickness and hardness, surface color brightened and formation of porous defects in the AAO films. The burning voltage was found to decrease with increasing solution temperature and decreasing magnetic stirring rate. The decreased burning voltages seem to be closely related with increased chemical reactions between AAO films and hydrogen ions.

• 한국연소학회:학술대회논문집
• /
• 2002.06a
• /
• pp.140-146
• /
• 2002

The tulip-inversion of flames in half-open tubes was investigated experimentally. Experiments was carried out in tubes with various shapes. The image of a flame propagation were pictured by HICCD(High speed intensified CCD) and the dynamic pressure of tubes was measured by a piezo pressure sensor. By analyzing the images of the flame propagation, we found the time and the distance for the occurrence of tulip-inversion. Regardless of the shapes of tubes, time of tulip-inversion are similar and inversely proportional to the burning velocity. But distances have different tendency. In a straight tube, the distance of tulip-inversion increases when the burning velocity increases. But in a converging tube, the distance of tulip-inversion decreases when a burning velocity increases. And the distance of tulip-inversion in a converging tube is much smaller than the distance of tulip-inversion in a straight tube. These results are caused by the deceleration of a flame when the diameter of a hole in open-side of a tube is small. The deceleration causes little effect on the time of tulip-inversion.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.20 no.1
• /
• pp.37-42
• /
• 2016

In this study, we examined the burning rate of the uncured propellant (with and without a curing agent application) in order to inspect the process of the HTPB solid propellant. The burning rate of the uncured propellant, that did not contain the curing agent, was approximately 9.7 mm/s at 1000 psi. In relation to the curing time, the burning rate was constant. The propellant, with the curing agent application, was approximately 8.1 mm/s showed a tendency of slowing as it burned. When the cure reaction rate was low, in accordance to the time, there were small changes in burn rate. However, when the cure reaction rate was high, the difference in burning rate was increased. The burning rate of a fully-cured propellant was approximately 6.8 mm/s, which appeared to be the lowest in order.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.368-373
• /
• 2017

Control method for DACS with variable burning area is designed and the performance of the control method is analyzed by doing simulation at various conditions. DACS, which got solid propellant on board, is designed as end-burning type typically. End-burning type DACS has the merit of controlling pressure and thrust, but it discharges the combustion gas which does not using for getting thrust. Therefore, optimal design of propellant grain and burning area changes over time as a result. Variable burning area can be assumed as a disturbance and adaptive control method is useful for pressure control of DACS effected by disturbance.