• 한국연소학회지
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• 제21권2호
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• pp.22-28
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• 2016

High efficient and environment friendly combustion technologies are used to be operated an extreme condition, which results in unintended flame instability such as extinction and oscillation. The use of electromagnetic energy is one of methods to enhance the combustion stability and a microwave as electromagnetic wave is receiving increased attention recently because of its high performance and low-cost system. In this study, an experiment was performed with jet diffusion flames induced by microwave. Micro jet was introduced to simulate the high velocity of industrial combustor. The results show that micro jet flames had three different modes with increasing oxidizer velocity; attached yellow flame, lifted flame, and lifted partially premixed flame. As a microwave was induced to flames, the overall flame stability and blowout limit were extended with the higher microwave power. Especially the interaction between a flame and a microwave was shown clearly in the partially premixed flame, in which the lift-off height decreased and NOx emission measured in post flame region increased with increasing microwave power. It might be attributed to increase of reactivity due to the abundance of radical pool and the enhanced absorption to thermal energy.

• 화약ㆍ발파
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• 제33권3호
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• pp.21-28
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• 2015

본 연구의 목적은 연속적 폭굉속도(VOD) 측정시스템을 이용하여 상용 테르밋 반응 혼합제의 연속적인 연소전파거동을 측정하기 위한 방법을 제안하기 위함이다. 두 종류의 상용 VOD 센서(VOD PROBEROD-OS, VOD PROBEROD-HS)와 자체개발한 VOD 센서(VOD PROBEROD-ES)를 기존 연속적 VOD 측정시스템에 적용하여 테르밋 반응과정에서 발생하는 연소전파속도(VOC)를 측정한 결과, 자체 개발한 VOD PROBEROD-ES 센서만 정상적인 연속적 연소전파거동을 보여주었다. 결과적으로, 철재튜브 내 장전된 테르밋 반응 혼합제는 기폭점으로부터 100mm 이내에서 약 200m/s의 연소전파속도를 보였으며, 100mm와 300mm 구간에서 급작스럽게 증가하여 음속의 2배에 가까운 VOC를 나타내었다. 그 이후 서서히 증가하여 최종적으로 800m/s까지 증가하는 경향을 보였다. 이러한 결과는 테르밋 반응 혼합제를 이용하여 정상적인 VOC나 위력을 기대하기 위해서는 철재튜브 등으로 완전히 구속된 상태에 길이 300mm 이상 장전하여야 함을 의미한다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제29회 KOSCI SYMPOSIUM 논문집
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• pp.33-40
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• 2004

Combustion of coke/anthracite in an iron ore sintering bed is characterized quantitatively by introducing newly defined parameters related to propagation and thickness of combustion zone and maximum temperature. The parameters are obtained by sintering pot experiment and I-D, unsteady numerical model which treats solid material as multiple solid phases. Experiments and calculations are performed for various major operating parameters: air inlet velocity, different type of fuels which have different reactivity and diameter of the solid fuel. Effects of the operating parameters on the productivity and quality of the sintering process are investigated and evaluated quantitatively and the results show that optimized air supply rate and diameter of anthracite for replacement of coke can be obtained. This approach can be applied to other kinds of combustors for characterization of the combustion in the solid fuel beds.

• 오토저널
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• 제14권6호
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• pp.74-80
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• 1992

The purpose of this study is to improve the performance of gasoline engine. Combustion-characteristics orignated from supplying cylinder with fuel-air mixture which was formed by the rise of oxygen-concentration in air with oxygen-enriching membrane have been investigated. The results showed that the poor-limit of oxygen-concentration was increased by shortening combustion-duration because the rise of oxygen-concentration in fuel-air mixture resulted in the promotion of combustion-velocity. Also, the generation of large output of power was expected from combustion in proportion as the amount of oxygen was increased.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제26회 춘계학술대회논문집
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• pp.253-256
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• 2006

액체로켓의 연소실내 분무연소 현상을 해석하기 위해 비연소 반응의 연료와 산화제 액적의 분무유동을 해석하였다. 분무연소 모델로 DSF 모델과 Euler-Lagrange 방법을 사용하였다. 액적과 가스상 그리고 증발한 기체상의 커플효과는 PSIC 모델을 사용하여 계산하였으며 수치 해석 방법으로 SIMPLER 알고리즘과 QUICK Scheme을 사용하였다. 해석결과 연소실내 속도와 온도 분포를 알 수 있었고, 연료와 산화제의 몰분율 또한 알 수 있었다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
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• pp.118-123
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• 2004

The combustion characteristics of 0.03MW turbulent methane/oxygen diffusion flames have been investigated to give basic informations for designing industrial oxyfuel combustors. NOx reduction has become one of the most determining factors in the combustor design since 3-5% nitrogen is intrinsically included from the current oxygen producing processes. Flame lengths and NOx concentrations were measured by varying flow velocities with and without installing quarls. Flame stabilities are significantly enhanced by oxyfuel combustion in contrast to air-fuel combustion. Flame length decreases with increasing fuel or oxygen velocity because of the enhancement of turbulent mixing. NOx concentration was reduced with increasing flo velocities. This can be attributed to the entrainment of inert product gases into flame decreasing flame temperature. The installation of quarl on the burners rather increased NOx concentration since the quarl blocked the entrainment above the nozzles.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.1-8
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• 2005

This paper addresses the analysis of the combustion characteristics in the oil burner using swirl flow. The reduction of exhaust emissions and high efficiency combustion techniques of the industrial burner have been studied to conserve environmental resources. We make swirl burner equal to dimension of wide burner and it is turn round of the combustion gas in construction. For a vigorous inner flow possessde 3m/s velocity in combustion gas of two burners. In calculation, we make use of a densely mesh to detailed analysis. In this study, the effect of swirl flow on the combustion of a commercial burner is analysed by experimental and also simulative manner. The results show the swirl burner has 40% better efficiency and less emissions of CO, HC, NOx and Smoke.

• 한국연소학회지
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• 제22권4호
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• pp.43-50
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• 2017

In this study, the multi-environment probability density function(MEPDF) approach has been applied to numerically investigate Delft-Jet-in-Hot-Coflow(DJHC) turbulent flames under Moderate or Intense Low-oxygen Dilution (MILD) combustion condition. Computations are made for two different jet velocities(Re = 4100 and 8800). In terms of mean axial velocity, temperature, and turbulent kinetic energy, numerical results are in reasonably good agreements with experimental data even if there exist the noticeable deviations in downstream region. Based on numerical results, the detailed discussions are made for the essential features of the non-visible flame structure and MILD combustion processes.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.167-169
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• 2014

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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• 제5권2호
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• pp.9-17
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• 2000

A brief introduction is given on the conditional moment closure model for turbulent nonpremixed combustion. It is based on the transport equations derived through a rigorous mathematical procedure for the conditionally averaged quantities and appropriate modeling forms for conditional scalar dissipation rate, conditional mean velocity and reaction rate. Examples are given for prediction of NO and OR in bluffbody flames, soot distribution in jet flames and autoignition of a methane/ethane jet to predict the ignition delay with respect to initial temperature, pressure and fuel composition. Conditional averaging may also be a powerful modeling concept in other approaches involved in turbulent combustion problems in various different regimes.