• 한국연소학회:학술대회논문집
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• 한국연소학회 2002년도 제25회 KOSCI SYMPOSIUM 논문집
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• pp.193-207
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• 2002

The present study is mainly motivated to investigate the vaporization, autoignition, and combustion of liquid fuel spray injected into high pressure environment. In order to represent these phenomena realistically, discrete droplet model (DDM) which simulates the spray using finite number of representative droplets was adopted for detailed consideration of the finite rate of uansport between liquid and gas phases. The Eulerian-Lagrangian formulation was used to analyze the two-phase interactions. The high pressure vaporization model was applied using the thermodynamic and phase equilibrium at droplet surface. The high pressure effect as well as high temperature effect was considered in the calculation of liquid and gas properties. The characteristics of spray in high pressure environment were explained by comparison with normal pressure case.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제27회 추계학술대회논문집
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• pp.175-178
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• 2006

인젝터의 특성을 고려한 분무연소 현상을 해석하기 위하여 연소실에 주입되는 연료와 산화제의 액적에 변동을 가해 연소실내 분무연소 현상을 수치적으로 해석하였다. 2차원 비정상 상태의 유동장을 QUICK Scheme과 SIMPLER Algorithm을 사용하여 계산하였고, 분무모델로는 DSF 모델과 Euler-Lagrange방법을 사용하였다. 연료와 산화제의 액적 변동은 사인 함수를 이용하여 모델링 하였고, 액적과 가스상의 커플효과와 가스상과 증발된 기체상의 커플효과는 PSIC 모델을 사용하여 계산하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2005년도 제24회 춘계학술대회논문집
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• pp.208-211
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• 2005

연소기 설계에 유용한 자료를 제공하기 위해 연소실내에서 연료와 산화제의 분무 연소에 관한 수치적 해석을 수행하였다. 분무 모델로 DSF 모델과 Euler-Lagrange 방법을 사용하였다. 액적 가열을 고려하여 액적의 온도 변화를 계산하였다. 액적과 가스상의 커플효과와 가스상과 증발된 기체상의 커플효과를 고려하기 위해 PSIC 모델을 사용하여 계산하였다.

• 한국분무공학회지
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• 제14권4호
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• pp.163-170
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• 2009

The present study has numerically investigates the vaporization, auto-ignition and combustion processes in the high-pressure and high-temperature conditions encountered in the diesel engine. 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 compared to conventional hydrocarbon liquid fuels, the sequence of the comparative analysis has been systematically made for DME and n-Heptane liquid fuels. Computations for DME fuel are made for two cases including constant fuel mass flow rate condition and fixed heat release rate. Based on numerical results, the discussions are made for the detailed combustion processes of DME and n-Heptane spray.

• 센서학회지
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• 제14권5호
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• pp.313-321
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• 2005

Spray combustion has been used in many industrial fields, for instance, such as diesel engines, gas turbines and industrial furnaces, and furthermore various measurement techniques have been applied to elucidate the phenomenon of spray combustion. In order to measure simultaneously the droplet velocity and the droplet size of spray, phase doppler anemometry (PDA) was frequently used in spray combustion. However, the measurement error is occurred due to existence of flame, which is considered as influencing the precision of measurement. Therefore, the purpose of this study is experimentally to conduct the systematic evaluation on the measurement error when PDA measurement is applied to combustion field.

• 한국연소학회지
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• 제10권4호
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• pp.18-23
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• 2005

This study focused on the use of orimulsion in industrial combustion systems. Orimulsion is a bitumen-in-water emulsified fuel, which contains a thirty percent water. Orimulsion has relatively high levels of sulfur and nitrogen compared to many fuel oils, and has been the subject of much debate regarding the environmental impacts of its use. The goal of this research is to analyze the effect of flash spray combustion characteristics of orimulsion on NOx and particulate material reduction. For the flash spray of orimulsion, it is heated to $150^{\circ}C$. The effects of fuel heating temperatures on NOx and particulate material emissions were investigated experimentally. As the fuel temperature was increased, NOx and particulate material concentrations in flue gas were decreased.

• 한국분무공학회지
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• 제25권2호
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• pp.51-59
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• 2020

The purpose of this study is to propose and compare methods for measuring individual spray cone angles using spray cross-section images. In direct injection gasoline engines, it was believed that the distribution of air-fuel mixture in the combustion chamber directly affected combustion performance and emission formation. However, since gasoline direct injection (GDI) injectors have a small injection angle, interference between individual spray plumes occurs. Therefore, GDI injectors have only measured the spray angle of the entire spray. To overcome these limitations, three methods of indirectly measuring the spray cone angles of individual spray plume were presented and compared by forming sheet beams using Nd:YAG laser and acquiring spray cross-section images. Each method currently has advantages and disadvantages, and research to apply the method suitable for various GDI injectors needs to be continued.

• 한국분무공학회지
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• 제5권4호
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• pp.33-39
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• 2000

The behavior of the 2-stage spray was studied by using the schlieren method with the high pressure common-rail injection system. The spray injected 2 times with the interval of $0.3ms{\sim}1.5ms$ between the 1st and the 2nd spray in a modeled combustion chamber of constant volume bomb. In this case, the quantity of injected fuel of 1st and 2nd also changed. The schlieren photograph shows that the 2nd spray goes further away than the 1st spray when the quantity of the 1st spray is less than that of the 2nd spray. The dispersion of the vapour to the combustion chamber is not affect in a 10% of 1st spray quantity. When the 1st spray quantity is more than the 2nd spray, the vapour scattering of spray is good.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
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• pp.207-214
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• 2004

Extra heavy vacuum residue oil has advantage as the fuel of a power plant in reducing the cost of power generation. Numerical study is conducted by the KIVA code to understand combustion, heat transfer and flow field characteristics in the test reactor. The combustion model of pulverized coal particles is adopted as the combustion process of extra heavy oil is similar to that of coal. As an initial phase of investigation parametric study is performed with respect to SMD and spray angle of injected spray droplets.

• International Journal of Automotive Technology
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• 제3권1호
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• pp.17-26
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• 2002

The authors have reported significant reductions in particulate emissions of diesel engines by generating strong turbulence during the combustion process. This study aims to identify optimum conditions of turbulent mixing for effective soot reduction during combustion. The experiments were conducted with a constant volume combustion vessel equipped with abet-generating cell, in which a small amount of fuel is injected during the combustion of the main spray. The jet of burned gas from the cell impinges the main flame, causing changes In the mixing of fuel and air. Observation was made for a variety combinations of distances between spray nozzle and Jet orifice at different directions of impingement. It Is shown that compared with the case without Jet flame soot decreases when the jet impinges. When the jet is very close to the flame, it penetrates the soot cloud and causes little mixing. There were no apparent differences in the combustion duration when the direction of impingement was varied, although the mechanisms of soot reduction seemed different. An analysis of local turbulent flews with PIV (Particle image Velocimetry) showed the relationship between the scale of the turbulence and the size of the soot cloud.