• Proceedings of the Korean Society of Marine Engineers Conference
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• 2000.05a
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• pp.45-51
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• 2000

Investigators who study on combustion in the cylinders of reciprocating piston type internal combustion engines have been encountered embarrassments due to the difficulties of adjusting specific parameter without interfacing other parameters such as cylinder wall temperature composition of gas in the cylinder existence of cylinder lubricant etc. Rapid compression-expansion machine the position and speed of piston of which are able to be controlled by means of a system controlled electrically and speed of piston of which are able to be controlled by means of a system controlled electrically and actuated hydraulically could be utilized as one of the most preferable countermeasures against those difficulties. Several units of rapid compression-expansion machines were developed but the speed up of frequency of piston movement still is the problem to be improved to cope with actual speed of internal combustion engines. Authors designed and manufactured a new rapid compression-expansion machine electrically controlled hydraulically actuated and computer programed and then examined the performance of one. Results of a set of experiments revealed acquirements of certain improvement of frequency of piston movement preserving the stability of system response and reproducing accurate compression ratio of cylinder those are the key function for the in-cylinder combustion experiments of internal combustion engines.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.5
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• pp.69-75
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• 2000

Investigators who study on combustion in the cylinders of reciprocating piston type internal combustion engines have been encountered embarrassments due to the difficulties of adjusting specific parameter without interfacing other parameters such as cylinder wall temperature, composition of gas in the cylinder, existence of cylinder lubricant etc. Rapid compression expansion machine, the position and speed of piston of which are able to be controlled by means of a system controlled electrically, and actuated hydraulically could be utilized as one of the most preferable countermeasures against those difficulties. Several units of rapid compression expansion machines were developed but the speed up of frequency of piston movement still is the problem to be improved to copy with actual speed of internal combustion engines. Authors designed and manufactured a new rapid compression-expansion machine electrically controlled, hydraulically actuated, and computer programed and then examined the performance of one. Results of a set of experiments revealed acquirements of certain improvement on frequency of piston movement preserving the stability of system response and reproducing accurate compression ratio of cylinder, those are the key function for the in-cylinder combustion experiments on internal combustion engines.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.5
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• pp.31-36
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• 2007

Combustion performance characteristics of subscale high-pressure combustor were investigated at 70 bar combustion pressure. All tests were successfully performed without any damage on the combustor. The mixing characteristics and distribution pattern of the injectors were found to have considerable influence on the combustion performance. The characteristic velocity of the combustor was higher in the injector with internal mixing than that of external mixing and in the injector with smaller mass flowrate. The pressure fluctuations at the propellant manifolds and the combustion chamber were measured to be less than 3% of the mean combustion pressure to meet the combustion stability criterion and to prove stable combustion characteristics of the combustor.

• Fire Science and Engineering
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• v.17 no.1
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• pp.33-39
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• 2003

The purpose of this study is to evaluate flame retardant performance, thermal stability and toxicity of combustion gases for some commercial wallpapers. ID evaluate flame retardant performance 45 degree combustion experiment method was used and thermal stability was evaluated using DSC and TGA apparatus (OSC-50/Shimadzu, TGA2050/TA Instruments Inc) . Concentrations of CO, $CO_2$, HCN and HCI were measured with (GASTEC/Japan, MSA400 Gas Monitor/Infitron Inc) and toxicity indices using NIST N-Gas Model were applied to evaluate the toxicity of combustion gases. The evaluation produced the following results : First, paper cork and PVC wallpaper treated with flame retardants were found to be suitable for flame retardant performance standards. Second, paper, cork and PVC wallpaper non-treated with flame retardants were shown to be relatively more hazardous because they had greater calorific values and a faster decomposition time than the flame retardant treated wallpapers. Third, the toxicity indices of non-treated wallpapers were found to be higher than those of treated wallpapers, and the toxicity index of PVC wallpapers was higher than those of paper and cork wallpapers.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2001.11a
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• pp.5-5
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• 2001

No Abstract, See Full Text

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.6
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• pp.1298-1307
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• 2001

Recently, the efforts to improve fuel economy and to reduce pollutant emission have become the main subject in the development of a gasoline engine. A lean combustion engine admitted as the best alternative is relatively lower fuel consumption rate and exhaust emissions. In this study, it is focused on intensifying intake flow field as one of methods to improve the performance of the lean combustion. First, three different types of suitable swirl control valve(SC7) with high swirl and tumble ratio are selected through steady flow experiment, being installed in a spark ignition engine. The relationship between lean misfire limit and torque was investigated with injection timing and spark ignition timing. Also, the effect of intensified swirl new on the combustion Stability and exhaust emissions was experimently examined by the measuring in-cylinder pressure and combustion variation. The results show that the engine with swirl control calve is superior to other conventional engine on the lean misfire limit, specific torque, combustion variation and emission, and the appropriate injection timing and spark ignition timing exist according to the type of swirl control valve.

• Journal of the Korean Institute of Gas
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• v.24 no.4
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• pp.25-31
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• 2020

Experimental investigations were conducted to examine the combustion characteristics of a swirl-stabilized double cone premixed burner nozzle used for industrial gas turbines for power generation. Several variants with different fuel injection patterns are tested to compare the combustion characteristics such as NOx and CO emissions, stability, and wall temperature distributions. Main results show that NOx emissions and stability are decreased either when the fuel hole diameter is decreased with the same number of fuel holes, or when the number of fuel holes is reduced with the same total area of fuel holes, both of which are due to a higher penetration of fuel into the air stream. Not only is NOx reduced but also stability is enhanced when the fuel hole diameter varies in an alternating manner with the same total area of fuel holes, showing that NOx reduction is due to a higher penetration of mean fuel injection path while stability enhancement is due to a lowered penetration of minimum fuel injection path.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.2
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• pp.170-177
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• 2005

The fuel-lean premixed flame has been considered one of the most efficient ways to reduce $NO_X$ emission during a combustion process. However, it is difficult to achieve stable fuel-lean premixed flames over the wide range of equivalence ratios: therefore, the application of fuel-lean flames to a practical combustion system is rather limited. In this study, the stability characteristics of fuel-lean flames stabilized by fuel-rich flames are investigated experimentally using a slot burner as a part of the basic research for practical application such as lean burn engines. Spontaneous emission of radical species were examined to understand the stability mechanisms of rich-lean premixed flames. The presence of fuel-rich flames could significantly lower the lean limit of fuel-lean flames. The stability of a fuel-lean flame is enhanced with the increase of fuel flow rate in a fuel-rich flame; how ever, it is not sensitive to the equivalence ratio of fuel-rich flames in the range of 1.2-2.4. The mechanisms of stable rich-lean premixed flames could be understood based on the characteristics of triple flame.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.188-196
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• 2004

To optimize and limit the axial length of baffle in KSR-III engine, stability rating tests using pulse gun as one of artificial disturbance devices have been done. Decay time and other parameters for the evaluation of stabilization ability of engine to external perturbation have been analyzed to quantify stabilization capacity of engine, in other words, dynamic stability margin. If baffle does not cover flame zone enough which can be considered as collision region of injector, it wasn't be able to suppress external perturbation sufficiently. The limit of combustion stability margin of engine is assumed to be 50 mm length baffle.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.401-406
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• 2020

NOx (nitrogen oxide) in the exhaust gas engines causes severe air pollution. NOx is produced under high-temperature combustion conditions. EGR (exhaust gas recirculation) is normally used to reduce the combustion temperature and NOx production. As the EGR ratio increases, the NOx level becomes low. On the other hand, an excessively high EGR ratio makes the combustion unstable resulting in other air pollution problems, such as unburned hydrocarbon and higher CO levels. In this study, the improvement of fuel droplets moving by the radiation of sonic waves was studied for the stable combustion using analytic and experimental methods. For the analytical study, the effects of the radiation of a sonic wave on the fuel droplet velocity were studied using Fluent software. The results showed that the small droplet velocity increased more under high-frequency sonic wave conditions, and the large droplet velocity increased more under low-frequency sonic wave conditions. For the experimental study, the combustion chamber was made to measure the combustion pressure under the sonic wave effect. The measured pressure was used to calculate the heat release rate in the combustion chamber. With the heat release rate data, the heat release rate increased during the initial combustion process under low-frequency sonic wave conditions.