• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.191-194
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• 2014

The characteristics of laminar free jet flow with having applied AC electric fields have been investigated experimentally. A single electrode configuration was adopted such that electric fields were applied directly to nozzle and thus the surrounding could be an infinite ground. The experimental results showed that the jet flow with AC was modified significantly. At a certain axial distance, the laminar fuel stem was broken down and subsequently it was separated into three parts when AC electric fields were applied over a certain voltage in a range of frequencies less than 120 Hz. The breakdown point was measured by varying applied AC voltage and frequency. The effect of applying electric fields to jet flow was discussed in detail.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.383-386
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• 2014

The characteristics of gas free jet flows in laminar with having applied electric fields have been investigated experimentally. A single electrode configuration was adopted such that electric fields were applied directly to nozzle and thus the surrounding could be an infinite ground. The experimental results showed that breakdown point at laminar flow has been measured by varying the applied voltage and frequency of AC. The effect of applying electric fields to free jet flow in laminar was discussed in detail.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
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• pp.67-74
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• 2004

Numerical analysis code has been developed for investigating the combustion characteristics in a slab heater of a steel mill company. Unsteady full 3-Dimensional behaviour can be predicted with the code. Premixed flame model is adopted for combustion phenomena. And eddy dissipation model is used for turbulent flow and non gray FVM method for radiation. Slab movement can be fully traced from entrance into heater until it's exit and computation is performed during that period. Code was validated by comparing the calculation results with experimental ones for the bench scale heater.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.229-232
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• 2007

고체 추진제 연소 현상을 해석할 때 요구되는 이동 경계면에 대한 수치 기법을 연구하였다. Eulerian 좌표계에서는 Ghost-Cell Extrapolation 기법을 적용하였고, Non-Eulerian 좌표계에서는 Lagrangian 기법을 적용하여 이동 경계면을 해석하였다. 도관 내 일차원 자유 피스톤 운동을 이 수치 기법으로 해석하여 이론 결과 값과 비교 검증하였다.

• 한국연소학회:학술대회논문집
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• 대한연소학회 2003년도 제27회 KOSCO SYMPOSIUM 논문집
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• pp.185-193
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• 2003

Basic flow fields of two dimensional V flames were examined as a preliminary work to study the instability of premixed flame with vorticity generation. Laminar premixed propane and methane flame were anchored by electrically heated wire to make two dimensional V flames. Flow fields were measured mainly by PIV(Particle Image Velocimetray) and the results were compared with those obtained by LDV(Laser Doppler Velocimetry) to confirm their reliability. Because the curvatures of V flames are so small, V flames were locally assumed to be inclined planar flames in gravitational field. The measured flow fields were locally compared with those of analytical solutions, which showed the qualitatively similar results. In downstream region, the vorticity fields were nearly constant except region near the center line, which support the assumption of locally one dimensional flame. Besides it was tried to find experimentally the similarity of flow fields in downstream region. Finally, stability diagram of propane and methane flames were drawn for the equivalence ratio less than one and the wide range of mean velocity.

• 한국자동차공학회논문집
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• 제4권1호
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• pp.28-35
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• 1996

In this paper, we study effect of the factors, participating in the combustion as the initial conditions, such as the flow characteristics of the mixture and the initial temperature, pressure and equivalence ratio in the chamber on the ignitability of the mixture, the combustion duration and the maximum combustion-pressure. The experiment was performed in a constant-volume combustion chamber, with turbulent flow inside, equivalent to the actual engine at TDC. The present experiment utilizes three devices which differ from each other in the distribution and the magnitude of discharge energy.

• 대한기계학회논문집
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• 제16권12호
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• pp.2385-2394
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• 1992

본 연구에서는 1차원, 2상 모델중 K.K.Kuo의 2상 유체역학 모델을 사용하여 유동을 수치해석하였다.

• 대한기계학회논문집B
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• 제20권3호
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• pp.979-987
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• 1996

A theoretical study for the laminar round jet diffusion flame impinging on the wall was carried out to predict the characteristics and structure of impinging jet flame and heat transfer to the wall. Finite chemistry via Arrhenius equation was adopted as the combustion model. All the transport properties were considered as the variable depending on the temperature and composition. For the parametric study, the distance from nozzle to perpendicular wall and Reynolds number at nozzle exit were chosen as the major parameters. As the results of the present study, the characteristics of flow field and the distributions of temperature, density and each chemical species were obtained. The heat transfer rate from flame to the wall and the effective heating area were calculated to investigate the influence of the major parameters on the heat transfer characteristics.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 1999년도 제12회 학술강연회논문집
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• pp.16-16
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• 1999

램 가속기 탄체 형상에 따른 가속 특성에 대한 연구는 열적 질식 모드에 대하여 Washington 대학, ISL 연구소 등에서 실험적으로 수행되어 졌으나 초폭굉 연소 모드에 대해서는 아직 미비한 실정이다. 초폭굉 연소 모드 램 가속기의 기본적인 탄체 형상은 원추-원통-원추로 이루어진 형상으로 탄체 전면에 형성된 경사 충격파가 탄체와 가속기 사이에서 반사되며 데토네이션파를 발생시켜 가속하게 된다. 탄체의 형상에 따라서 탄체 주위에 형성되는 충격파 구조는 차이를 나타내게 되고 발생되는 데토네이션파의 위치와 강도를 따라서 탄체의 가속특성은 상당한 차이를 나타낸다. 기본적으로 탄 체의 전면 형상은 경사 충격파의 강도와 단체 주위의 유동장의 특성을 결정하는 주요 요인이고 이에 따라 데토네이션파의 형성과 안정화 역시 결정되어 탄체의 가속 특성을 결정짓는다. 또한 데토네이션파를 임의의 위치에 형성하기 위해 이중 원추형상의 충격파-충격파 상호작용을 이용하여 데토네이션파를 발생시켜 탄체를 가속시킨다.

• 한국화재소방학회논문지
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• 제26권5호
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• pp.105-110
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• 2012

본 연구는 수치적 접근방법을 통해 스프링클러 분무가 화재공간내부 유동특성에 미치는 영향을 파악하고자 한다. 화재유동 및 분무유동장 해석을 위해 적용된 수치해석모델은 FDS 5.5.3이며 격자독립성시험을 통해 최적 격자를 선정하였다. 수치해석 모델의 타당성을 검증하기 위해 Magnone 등이 수행한 실험결과와 비교 분석을 수행하였으며 FDS 모델에 의해 계산된 화재공간 내부의 온도분포는 실험결과와 비교적 잘 일치하였으나 스프링클러 분사유량이 증가함에 따라 오차는 증가하는 경향을 보였다. 또한 이전 연구와 같이, FDS 계산결과는 스프링클러 분무에 의해 화재실 출입구를 통한 연소생성물의 유출질량유량이 감소하는 것으로 나타났다. 본 연구는 스프링클러 분무가 포함된 화재유동장에 대한 모델의 타당성을 확보하고 스프링클러 시스템의 최적화에 기여할 수 있다.