• 한국연소학회:학술대회논문집
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• 2003.05a
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• pp.7-12
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• 2003

The purpose of this work is to investigate the effect of premixing condition on the combustion and exhaust emission characteristics in a HCCI diesel engine. To form homogeneous charge before intake manifold, the premixed fuel is injected into premixed tank by GDI injection system and the premixed fuel is ignited by direct injected diesel fuel. But in the case of high intake air temperature, premixed fuel is auto-ignited before diesel combustion and soot emission is increased. In the case of light load condition, the BSFC is improved by intake air heating because increased air temperature promoted the combustion of premixed mixture. NOx and smoke concentration of exhaust emissions are reduced compared to conventional diesel engine. The combustion characteristics of the HCCI diesel engine such as combustion pressure, rate of heat release, and exhaust emission characteristics are discussed.

• Journal of the Korean Society of Combustion
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• v.8 no.1
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• pp.17-24
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• 2003

The conventional regenerative system has a high thermal efficiency as well as energy saving using the high preheated combustion air. in spite of these advantages, it can not avoid high nitric oxide emissions. Recently, flameless combustion has received much attention to solve these problems. In this research, numerical analysis is performed for flow-combustion phenomena in the self regenerative burner. In this analysis we used Fluent 6.0 code. the that is developed for commercial use, Methane gas is used as a fuel and two-step reaction model for methane and Zeldovich mechanism for NO generation are used. the velocity of the preheated combustion air is used as a parameter and we analyze the characteristics of flow-field, temperature distributions and NO emissions. Due to the increased recirculation rate, the maximum temperature of flame is significantly increased and NOx emissions is reduced.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.1
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• pp.55-63
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• 2003

In a diesel engine, air-fuel mixture formation and ignition delay period have great influence on the performance of engine. Their main factors are combustion chamber shape, fuel injection system. air volume, air flow and so on. So, the combustion process in the cylinder is complex because of many factors which have direct and indirect effects on it. In this study, we take into consideration of scavenging pressure and scavenging temperature that are hewn as the main factor to the combustion process of two-stroke D.1. diesel engine. It is taken a picture of the combustion flame process for combustion chamber of re-entrant type and cylindrical type. So, it is applied to the basis data of combustion chamber design from an image analysis.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.339-342
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• 2014

Rotary kiln produces lime from limestone through thermal decomposition. Ring formation in kiln internal wall is known issue that decreases productivity. The cause of ring formation is temperature imbalance as flame leans toward upper wall. Therefore, burner nozzle geometry was changed to improve air-fuel mixing state which leads to prevention of ring formation. CFD simulation and experimental test were performed in this study to investigate the effect of air-fuel mixing on flame structure, temperature and $NO_X$ concentration. It is shown that combustion efficiency has been enhanced and $NO_X$ concentration has been decreased by using swirl flow for secondary combustion air. It's also shown that flame has been straightened by using straight flow for secondary combustion air.

• Journal of Advanced Marine Engineering and Technology
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• v.6 no.1
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• pp.34-40
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• 1982

The characteristics of typical 17 kinds of fuel oils are studied to fine the calculation formulae for the required amount of air and the combustion gas amount. 1) The author's calculation formulae are as follows; (1) Theoretically required amount of air (2) Theoretical amount of combustion gas 2) Theoretical amount of the required air in combustion and combustion gas of fuel oils are always estimated less with Rosin's formula than with author's one. 3) Theoretical amount of the required air and the amount of combustion gas of fuel oils are more reasonable with author's formula than Rosin's one in comparison with results of actual analysis.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.3
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• pp.129-139
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• 1995

This study investigates the combustion characteristics of methane-hydrogen-air premixture in a constant volume combustion chamber. Primary factors of the combustion characteristics of methane- hydrogen-air premixture are the equivalence ratio and hydrogen supplement rate. In the case of $\phi$= 1.1, maximum combustion pressure and heat release rate have peaks, and they increase as the initial pressure and hydrogen supplement rate increase. The total burning time is also the shortest at the $\phi$= 1.1, it shorten by lowering the initial pressure and by increasing the hydrogen supplement rate. The maximum flame temperature is shown at the $\phi$= 1.0, and increasing the initial pressure and hydrogen supplement rate, it increases. The concentration of NO reveals the highest value at the $\phi$= 0.9, and it increases by increasing the initial pressure and hydrogen supplement rate. It is also found that the limit of lean inflammability of methane-hydrogen-air premixture is greatly widened by increasing the hydrogen supplement rate.

• Journal of Advanced Marine Engineering and Technology
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• v.5 no.1
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• pp.28-33
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• 1981

The characteristics of typical 35 kinds of domestic anthracites among 155 kinds are studied to find the calculation formula for the required quantity of air and the combustion gas quantity. 1) The author's calculation formulae are as follows: ${A_0}={\frac{1, 000}{1, 064}}{H_1}+0.086(Nm^3/kg)$ ${G_0}={\frac{1, 000}{1, 110}}{H_1}+0.234(Nm^3/kg)$(1) Theoretically required quantity of air (2) Theoretical quantity of combustion gas 2) Theoretical quantity of air in combustion of domestic anthracite is always estimated more with Rosin's formula than author's one in the typical domestic anthracites which have the lower calorific value between 3, 000-8, 000 Kcal/kg and the difference of the calculated quantity of air becomes small, as the calorific value increases. 3) Theoretical quantity of combustion gas is estimated more by author's formula than by Rosin's one with the domestic anthracites which have more calorific value than 6, 700 Kcal/kg and is estimated less in the under range of the above calorific value. 4) Theoretical quantity of required air and quantity of combustion gas of domestic anthracite show ${\pm}$4% difference by Rosin's formulae in comparison with results of actual analysis, and about ${\pm}$1.5% by the author's one.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.41-44
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• 2014

This study focused on the effect of the biomass blended ratio on air-staged pulverized coal furnace. The hybrid NOx reduction technology between fuel blending and air staging has been applied in an air-staged pulverized coal fired furnace. The results indicated that co-firing biomass with coal could reduce NOx emissions in an air-staged combustion. In addition, carbon burnout and flame temperature increased under the air-staged condition. A dominant synergistic effect on NOx reduction and carbon burnout was observed when biomass co-firing with coal was applied in air staged combustion.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.8
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• pp.1089-1096
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• 2003

An experiment was performed to investigate lift-off, blow-off and combustion characteristics of a lifted coaxial diffusion flame according to fuel jet and air velocity. A jet diffusion flame which is attached on the nozzle rim begins to be lifted with increase of air velocity, and finally becomes blow-off at higher air velocity. In experiment, blow-off limit increased with increase of fuel jet velocity, however lift-off occurred at lower air velocity. Flame structure and combustion characteristics were examined by schlieren photos, temperature distributions and emission concentration distributions. Flame temperature became higher at midstream and its RMS became larger at up and downstream with increase of air velocity. Local NO concentration decreased but $CO_2$concentration increased with increase of air velocity, which shows combustion reaction becomes close to be stoichiometric at higher air velocity in spite of lift-off.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.476-479
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• 2008

The combustion efficiency of the solid fuel ramjet is affected by the inlet air temperature. And this inlet air temperature is dependent on the flight Mach number and the environment air temperature. If the flight altitude is changeable, the inlet air temperature and the air density also vary. The performance efficiency is investigated with this variables related to the combustion efficiency.