• 한국연소학회지
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• 제7권2호
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• pp.1-6
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• 2002

Characteristics of laminar lifted flames of propane highly-diluted with nitrogen have been investigated at various temperatures of coflow air. At various fuel mole fractions, the base of laminar lifted flames has the structure of tribrachial (or triple) flame. The liftoff heights are correlated well with the stoichiometric laminar burning velocity considering initial temperature at a given coflow velocity. It shows that lifted flames are stabilized on the basis of the balance mechanism between local flow velocity and the propagation speed of tribrachial flame, regardless of the temperature of coflow and fuel mole fraction. Lifted flames exist for a jet velocity even smaller than the stoichiometric laminar burning velocity, and liftoff velocity increases more rapidly than stoichiometric laminar burning velocity as coflow temperature increases. These can be attributed to the buoyancy effect due to the density difference.

• 한국연소학회지
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• 제18권2호
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• pp.8-16
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• 2013

The flameless combustion has been considered as one of the promising combustion technology for high thermal efficiency, reducing NOx and CO emissions. In this paper, the effect of air and fuel injection condition on formation of flameless combustion was analyzed using three dimensional numerical simulation. The results show that the high temperature region and the average temperature was decreased due to increase of recirculation ratio when air velocity is increased. The average temperature was also affected by entrainment length. Generally mixing effect was enhanced at low entrainment length and dilution was dominated at high entrainment length. This entrainment length was greatly affected by air and fuel injection velocity and distance between air and fuel. It is also found that the recirculation ratio and dilution effect were generally increased by entrainment length and the recirculation ratio, mixing and dilution effect are the significant factor for design of flameless combustion system.

• 한국해양공학회지
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• 제10권3호
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• pp.117-124
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• 1996

A fluidized bed combustion chamber is widely used to incinerate waste material. The most important factor designing the incinerator is the flow characteristics in a fluidized bed, because combustion efficiency is influenced by the flow characteristics. This paper has invesitigated the flow characteristics of bubbles in fluidized bed by means of meassuring a pressure fluctuation in the fluidized bed. A pressure probe system has used to measure the pressure. The data concerned with bubble rising velocity, bubble size, distribution of bubbles and frequency of bubble generation or decay are obtained to find the flow characteristics of bubbles in the fluidized bed. The result obtained from this experimental study can be used to design the fuel feeding system of fluidized bed combustion type incinerator. And it is possible to predict the mixing of waste material and fluidizing material.

• 한국연소학회지
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• 제18권4호
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• pp.21-28
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• 2013

HCCI engines have mainly focused on achieving low temperature combustion in order to obtain higher efficiency and lower emission. One of practical difficulties in HCCI combustion is to control the start of combustion and subsequent combustion phasing. The choice of primary reference fuels in HCCI strategy is one of various promising solutions to make HCCI combustion ignition-controlled. The behavior of ignition delay to the frequency variation of sinusoidal velocity oscillation is computationally investigated under HCCI conditions of PRF75 using a reduced chemistry in a counterflow configuration. The second-stage ignition is more delayed as the higher frequency is imposed on nozzle velocity fluctuation whereas the first-stage ignition is not much influenced.

• Journal of Advanced Marine Engineering and Technology
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• 제30권1호
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• pp.102-108
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• 2006

On the refutation demanded for a control of various toxic substances. PCBs(poly chlorinated biphenyl) has a fatal poisonous matter in the ecosystem and the environmental pollution as it Is a kind of stable chemical substance. Especially, the gross Product of PCBs is estimated at about one million tonnage all over the world. However it is kept on storing in untreated state, then has a deterioration by the Prolonged storage and a risk of overflowing. Therefore, this research examined the fundamental characteristics of combustion and emission for the target of using the IPA (iso-propyl alcohol) solution as a part of PCBs control. IPA was filled to three kinds of Vessel, i.e. Vessel I, II, and III, and then was investigated as follows combustion shape, flame temperature. mass burning velocity, and PM(Particulate matter). A radial thermometer and a C-A thermocouple measured the flame temperature, and the optical extinction method by using He-Ne laser and the filter weight method used in the PM measurement. As a result, with an increasing of L/S ratio, the flame length become shorter and the burning velocity is more rapid, but the particulate matters is higher. It is supposed that the air flow rate is high on Vessel. and then the combustion is Promoted in the surface area of the upstream zone. The future works plan to investigate the characteristics with an using of the mixing of IPA and PCBs

• 대한기계학회논문집B
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• 제23권10호
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• pp.1248-1253
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• 1999

This study is concerned about the combustion characteristics of methane-air and methane/hydrogen-air mainly the behavior of burning velocity including the effect of the ignition energy. The experiments were conducted in a spherical combustion bomb designed in this laboratory. The burning velocities were measured by the pressure-time history and the reaction rates were estimated theoretically. The experimental results showed that the burning velocity increased by 25 to 50 percent when hydrogen is added to methane by 20 percent.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제30회 춘계학술대회논문집
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• pp.149-152
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• 2008

30톤급 액체로켓엔진 실물형 연소기의 형상에 따른 연소특성속도에 대한 연구를 수행하였다. 본 연구에서 연소기의 형상은 연소기 헤드와 분리가 가능한 내열재 및 채널 냉각형 연소실(${\varepsilon}$=3.2), 그리고 일체형인 팽창비가 각각 3.5와 12인 재생냉각형 연소기이다. 연소압력은 약 53${\sim}$60 bar 그리고 추진제 유량은 약 89 kg/s이고, 적용된 분사기는 리세스수가 1.0인 동축 와류형이다. 설계점 연소시험에서 팽창비가 12인 일체형 재생냉각 방식의 연소기가 가장 큰 연소특성속도를 보였는데 이는 추진제인 케로신이 분무되기 전 챔버 냉각으로 인한 온도 상승에 따른 엔탈피의 증가 및 연소압력의 증가에 기인한 것이다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.139-143
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• 2007

추가 30톤급 액체로켓엔진 실물형 연소기에서 수행했던 연소시험의 전반적인 성능결과에 대해 기술하였다. 연소기 연소압력은 약 53${\sim}$60 bar 그리고 추진제 유량은 약 89 kg/s이다. 30톤급 실물형 연소기는 연소기 헤드, SUS 배플, 배플분사기, 내열재 연소실, 냉각채널 연소실 그리고 재생냉각 연소실 등으로 구성하였다. 연소특성속도는 약 1673부터 1730 m/sec이며, 비추력은 약 254에서 263 sec 정도의 값을 얻었다. 일반적으로 분사기의 RN 증가에 따라 연소특성속도는 증가하였다. 또한, 연소기의 비추력은 연소특성속도 증가에 따라 증가함을 보여 주었다.

• 대한기계학회논문집
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• 제18권9호
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• pp.2423-2430
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• 1994

Several factors of the efficient combustion process are shape of combustion chamber, position of spark plug, turbulence flow and so on. the shape of combustion chamber and position of spark plug are constrained to geometrically, and then it could not make a change the shape easily. But the turlence flow in combustion chamber have a great influence on combustion phenomena, and which is much easier to control relatively. And since characteristics of turbulence flow would be very important to the stability of combustion and performances, This study is also essential to future engine-low emission and lean burn engine. This paper shows that the visualization of the turbulence flow of single cylinder engine by using 2way, $45^{\circ}$ inclined and 2 channel hot wire probe through the park plug hole. We also study the characteristics of turbulence flow by means of ensemble averaged mean velocity, turvulence intensity and integral length scale.

• 한국연소학회지
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• 제22권2호
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• pp.19-26
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• 2017

An experimental study investigates the flame response characteristics of jet-diffusion flame and premixed flame. The experiment was conducted while varying the amplitude. Flame lengths were quantified for OH chemiluminescence measurement and compared with the result of the flame transfer function. Flame length and flame velocity perturbation were normalized and compared with the result of the flame transfer function. The comparison results appear that velocity perturbation and flame length oscillation of premixed flame show linear behaviors on the other hand jet-diffusion flame, amplitudes are more thant 0.20, shows nonlinear behaviors of flame velocity perturbation and flame length oscillation.