• Journal of the Korean Chemical Society
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• v.59 no.4
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• pp.296-307
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• 2015

The purposes of this study were to develop the experiment for gas concentration measure during combustion of a candle and to investigate the application effect of the experiment. For this study, 15 elementary school teachers were selected by considering their gender, career, 6th grade science teaching experience, and 6th grade science teaching experience according to 2007 revised s cience curriculum. The experiment using MBL is designed to confirm gas concentrations visually during the combustion of a candle which burns in an acrylic container. The experiment method is as follows. 1) Make two sets of holes in the container and then insert oxygen sensors and carbon dioxide sensors in the holes. 2) Burn a candle in the container and observe the changes in the burning of the candle. The experiment has checked oxygen concentration and carbon dioxide concentration in real-time and displays gas concentration changes by graphs. The results of the application effect of the experiment are as follows. Most elementary school teachers who had not had scientific concepts on combustion got acquainted with scientific concepts about ‘the reason why a candle is blown out when it is covered with a bottle’, and ‘the concentrations of oxygen and carbon dioxide before and after combustion’. In addition, about half of elementary school teachers got acquainted with scientific concepts about ‘the definition of combustion’, and ‘distribution of carbon dioxide during combustion’. Thus, the experiment to measure gas concentrations during combustion is helpful to improve elementary school teachers’ concepts on combustion.

• 한국연소학회:학술대회논문집
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• 2013.06a
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• pp.117-119
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• 2013

Combustion stability margin of a model gas turbine has been assessed by utilizing damping ratios of measured dynamic pressure data. It is known that acoustic oscillations in combustion chambers can be described as a superposition of nonlinearly interacting oscillators. Based on this theoretical background, CSMA (Combustion Stability Margin Assessment) code has been developed. The code has been employed into a model gas turbine combustion experiment, focused on the combustion instability, to show its capability to determine the damping ratio of measured dynamic pressure and further to assess combustion stability margin of the experiment, and turned out that the code works well.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.3
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• pp.358-365
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• 2016

In this study, one-dimensional analysis under the assumption of an inviscid flow was conducted for the experiment initiated by the French-German Research Institute of Saint-Louis (ISL) in order to investigate the energy effect of aluminum combustion. Previous theoretical analysis based on the assumptions of isentropic compression and a constant specific heat derived by ISL claimed that the experiment was not affected by the heat of aluminum combustion. However, rigorous analysis in present investigation that considered the average properties behind the shock wave compression and temperature-dependent specific heat showed that the S225 experiment was partially affected by the aluminum combustion. The increase in heat due to aluminum combustion was estimated from the rigorous analysis.

• Journal of Korean Elementary Science Education
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• v.19 no.2
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• pp.15-27
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• 2000

The purpose of this study was to survey the thinking of children, preliminary elementary teachers and elementary teachers in relation to the experiment of candle's combustion in a bottle on the water, to develop some supplementary experiments for the correction of the misconception on this experiment and to propose a new teaching method for this subject-matter The results of this study can be summarized as follows. 1. Most of the answers are related to the simple observation as the extinguishing of candlelight and the water rising in the bottle after a candle's combustion. And it is appeared that all the groups are similarly short of the ability of experimental design to verify the cause and effect. 2. from the results of the developed supplementary experiments, it is concluded that the main cause of the water rising is not the combustion of oxygen, but the expansion of volume and the releasing of air in the bottle in the bottle by heat of candle's combustion. 3. Based on the above results, a new direction for the teaching method of this subject is proposed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.3
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• pp.359-364
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• 2004

For the development of high efficiency and low emission combustion systems, high temperature air combustion technology has been tested by utilizing preheated air over 1100 K and exhaust gas recirculation. In this system, combustion air is diluted with large amount of recirculated exhaust gases, such that the oxygen concentration is relatively low in the reaction zone, leading to low flame temperature. Since, the temperature fluctuations and sound emissions from the flame are small and flame luminosity is low, the combustion mode is expected to be flameless or mild combustion. Experiment was performed to investigate the turbulent flame structure and NO$_x$ emission characteristics in the high temperature air combustion focused on coflowing jet diffusion flames which has a fundamental structure of many practical combustion systems. The effect of turbulence has also been evaluated by installing perforated plate in the oxidizer inlet nozzle. LPG was used as a fuel. Results showed that even though NO$_x$ emission is sensitive to the combustion air temperature, the present high temperature air combustion system produce low NO$_x$ emission because it is operated in low oxygen concentration condition by the high exhaust gas recirculation.

• 한국연소학회:학술대회논문집
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• 2005.10a
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• pp.189-197
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• 2005

The usefulness of unsteady combustion was experimentally investigated using confined premixed flames stabilized by a rearward-facing step. For this purpose, apparatus of forced pulsating mixture supply, which could be modulated its amplitude and frequency, was designed. The unsteady combustion used in this experiment plays an important role in controlling self-excited combustion oscillations and furthermore it exhibits desirable performance, from a practical point of view, such as high combustion and reduction of pollutant emission like nitric oxide.

• 한국연소학회:학술대회논문집
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• 2001.06a
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• pp.46-52
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• 2001

In this study, the generation of oxygen-free gas using catalytic combustion for industrial applications is explained ; heat treatment and copper annealing. For the experiment, Pd catalysts were determined by testing their catalytic activities over LPG in a micro-reactor. Combustion characteristics for the generation of oxygen-free atmospheric gas and the effect of flue gas upon surface oxidation were estimated form this experiment. As a result of the experimental investigation, we can state that the catalytic combustion could generate oxygen-free atmospheric gas suitable for industrial applications, but vapor produced by combustion process must be carefully considered as a new factor of surface oxidation.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.1
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• pp.28-35
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• 1996

In this paper, we study effect of the factors, participating in the combustion as the initial conditions, such as the flow characteristics of the mixture and the initial temperature, pressure and equivalence ratio in the chamber on the ignitability of the mixture, the combustion duration and the maximum combustion-pressure. The experiment was performed in a constant-volume combustion chamber, with turbulent flow inside, equivalent to the actual engine at TDC. The present experiment utilizes three devices which differ from each other in the distribution and the magnitude of discharge energy.

• Journal of the Society of Disaster Information
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• v.16 no.2
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• pp.383-391
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• 2020

Purpose: To identify internal self ignition and ignition caused by external flames in energy storage rooms, and to analyze the difference between ignition due to overheating and ignition caused by external heat sources. Method: membrane melting point measurement, battery external hydrothermal experiment, battery overcharge experiment, comparative analysis of electrode plate during combustion by overcharge and external heat, overcharge combustion characteristics, external hydrothermal fire combustion characteristics, 3.4 (electrode plate comparison) / 3.5 (overcharge) /3.6 (external sequence) analysis experiment. Result: Since the temperature difference was very different depending on the position of the sensor until the fire occurred, it is judged that two temperature sensors per module are not enough to prevent the fire through temperature control in advance. Conclusion: The short circuit acts as an ignition source and ignites the mixed gas, causing a gas explosion. The electrode breaks finely due to the explosion pressure, and the powder-like lithium oxide is sparked like a firecracker by the flame reaction.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.325-329
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• 2017

In this study, the combustion experiment of hydrocarbon-kerosene fueled dual mode ramjet combustor was performed at mach number 3.5~6.0 conditions. Through the experiment, the temperature and the pressure distribution inside the combustion chamber were measured and the combustion characteristics inside the combustion chamber were investigated. In the mach number 3.5~5.0 range, it was able to identify subsonic combustion in the downstream combustion chamber. In the mach number 6.0 condition, the injected fuel from the injectors was naturally fired, and it was possible to confirm that supersonic combustion was successful in the upper chamber.