• 한국분무공학회지
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• 제13권2호
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• pp.91-98
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• 2008

In the present study, in order to understand the overall spray combustion characteristics of DME fuel as well as to identify the distinctive differences of DME combustion processes against the conventional hydrocarbon liquid fuels, the sequence of the comparative analysis have been systematically made for DME and n-heptane liquid fuels. To realistically represent the physical processes involved in the spray combustion, this studyemploys the hybrid breakup model, the stochastic droplet tracking model, collision model, high-pressure evaporation model, and transient flamelet model with detailed chemistry. Based on numerical results, the detailed discussions are made in terms of the autoignition, spray combustion processes, flame structure, and turbulence-chemistry interaction in the n-heptane and DME fueled spray combustion processes.

• 한국산학기술학회논문지
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• 제9권4호
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• pp.865-870
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• 2008

대형디젤 기관에서 매연배기가스에 대한 배기가스 재순환장치의 영향을 KIVA-3V 전산유체해석코드를 통해서 수치 해석적으로 연구했다. 지배방정식으로 RNG k-$\varepsilon$ 난류 모델을 이용했고, 무화, 벽 침투 그리고 매연 등의 물리적인 현상을 나타내기 위해서 TAB, Wave, Watkins-Park, Nagle-Strickland 모델이 적용되었다.

• Journal of Advanced Marine Engineering and Technology
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• 제28권7호
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• pp.1123-1130
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• 2004

Numerical simulations have been carried out to investigate the effect of nozzle hole geometry on the combustion characteristics of the large diesel engine. 6S90MC-C. Spray and combustion phenomena were examined numerically using FIRE code. Wane breakup and Zeldovich models were adopted to describe the atomization characteristics and NOx formation processes. Predictions on the cylinder peak pressure and NOx emission were first verified with the experimental data to confirm the reliability of numerical calculations. The comparison results showed good agreements within the range of 0.64% and 4.6% respectively. Finally, the effects of fuel spray angle and diameter on the engine performance were investigated numerically to find the optimum nozzle hole geometry considering fuel consumption, NOx emission and heat flux of the combustion chamber wall. It was concluded that the combustion gas recirculation in cylinder by changing fuel injection direction is an effective method to reduce NOx emission by about 10% with increasing fuel oil consumption, 1.4% in a large diesel engine.