• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.185-186
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• 2014

The multi-environment probability density function model has been applied to simulate the turbulent stratified premixed flames. The direct quadrature method of moments (DQMOM) has been adopted to solve the transport PDF equation due to its computational efficiency and robustness. The IEM mixing model is employed to represent the mixing process and the chemical mechanism is based on Gri 3.0 mechanism. Numerical results obtained in this study are precisely compared with experimental data in terms of unconditional and conditional means for scalar fields and velocity fields.

• 연구논문집
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• 통권25호
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• pp.129-135
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• 1995

This study discribes characteristics of water spray for extinguishment of gasoline pool fire. Experiments are carried out for the gasoline pool fire in a small tank with a diameter of 150mm and a height of 8mm. Droplet size, spray pressure, amount of water which reaches the flame base and velocity of water spray are measured to find extinguishment conditions and air entrainment due to the water spray is visualized. Critical conditions of water spray for extinguishment of gasoline pool fire is quantitatively shown.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제29회 KOSCI SYMPOSIUM 논문집
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• pp.213-216
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• 2004

The results of combustion performance test of fuel-rich gas generator(GG) using LOx and kerosene as propellant at design and off-design point are described. The parameters used in this analysis are the average exit temperature($T_{GG}$) and the characteristic velocity($C^{\ast}$). The average gas temperature at the exit of gas generator is found to be a function of propellant O/F ratio. For the gas generator having residence time of 4msec or more, the effect of flame residence time and combustion chamber pressure on the exit temperature is not significant. The exit characteristic velocity is found to be linearly proportional to the gas temperature at the exit of gas generator.

• Journal of Advanced Marine Engineering and Technology
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• 제35권7호
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• pp.907-913
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• 2011

Swirling flows are related to the spiral motion in the tangential direction in addition to the axial and radial direction using several swirl generators. These type of flows are used in combustion chambers to improve flame stability, heat exchanger to enhance heat transfer coefficients, agricultural spraying machines and some vertical pipes to move slurries or transport of materials. However, only a few studies three dimensional velocity profiles in a vertical pipe have been reported. In this present paper, 3 dimension particle image velocimetry(PIV) technique was employed to measure the velocity profiles in water along a vertical circular pipe with Reynolds number from 6000 to 13,000. A tangential inlet condition was used as the swirl generator to produce the required flow. The velocities were measured with swirling flow in the water along the test section using the PIV technique.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.249-251
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• 2014

Synthesis gas such as hydrogen and carbon monoxide was produced from $CH_4//oxygen$ mixture using two-section porous media combustor. Heat recirculation through the inner foam structure could extend the flow velocity of stable region over the laminar burning velocity. $H_2/CO$ ratio and module M from concentration of flue gas measured by Gas Chromatography was similar to those calculated by equilibrium. But it was made sure that the heat loss effect becomes more influential than heat recirculation effect as the mixture gets richer. To generate synthesis gas appropriate for methanol production, insulated pressurized porous media combustor will be designed and built in the future.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2001년도 제23회 KOSCO SYMPOSIUM 논문집
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• pp.17-26
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• 2001

Self flue gas recirculation flow is an effective method for low NOx emission in the regenerative low NOx burner. The object of this study is to analyze the self flue gas recirculating flow by varying jet velocity of the combustion air. Fuel and air flow rates are fixed and combustion air jet nozzle diameters are 13, 6.5 and 5mm. The stoichiometric line is obtained from the concentration of the fuel using an acetone PLIF technique. It is found that the self flue gas recirculating flow is entrained into that line using a two color PIV technique. As the jet velocity of combustion air is increased, the flue gas entrainment rate into the stoichiometric line is increased. This result suggests that NOx emission can be reduced due to the effects of flue gas which is lowering the flame temperatures.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2000년도 제20회 KOSCO SYMPOSIUM 논문집
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• pp.117-121
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• 2000

We developed a general purpose program for the analysis of flows in a gas turbine combustor. The program uses non-staggered grids based on finite volume method and the cartesian velocities as primitive variables. We calculated a flow inside the C-type diffuser to check the boundary fitted coordinate. The velocity profiles at cross section agree well with experimental results. We calculated turbulent diffusion flame behind a bluff body for the combustion simulation. Simulation shows two recirculating region like experimental results. Simulated velocity, turbulent kinetic energy, temperature and concentration distribution agree well with experimental data. Finally, simulation of axisymmetric flows with swirl shows two recirculating region like experimental results.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.691-694
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• 2008

Spray characteristics of the APU simplex fuel nozzle are investigated. Four flight conditions such as sea level idle, sea level max power, 20,000 feet idle, 20,000 feet max power are used as spray experimental conditions. Spray visualization was performed by using ND-YAG laser. Droplet size and velocity were measured by using PDPA(Phase Doppler Particle Analyzer) system. From the test result, SMD is 100 ${\mu}$m�� and velocity is 10 m/s at 20,000 ft idle condition. In this condition, flame unstability could be occurred due to the higher drop diameter. Therefore it is necessary to decrease the droplet diameter in the high altitude condition.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.925-930
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• 2000

This paper is investigated the entrainment of air into sprays which has significant effects on the combustion efficiency, stability of flame using the air-assisted twin-fluid nozzle in non-burning. The factors which may be expected to affect the entrainment of air by a liquid spray are: Relative velocity of droplet and ambient gas; Drop size and size distribution; Density and other property of the liquid. Here, axial, radial velocity and turbulent kinetic energy of spray droplet was measured with the PIV(Particle Image Velocimetry). Spray characteristics were also visualized using CCD camera. The results indicate that the entrainment rate increases more or less non-linearly with the downstream region.

• 한국연소학회지
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• 제14권2호
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• pp.32-41
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• 2009

The transported probability density function model combined with the consistent finite volume (FV) method has been applied to simulate the turbulent bluff-body reacting flows. To realistically account for the non-isotropic turbulence effects on the turbulent bluff-body reacting flows, the present PDF transport approach is based on the joint velocity- turbulent frequency-composition PDF formulation. The evolution of the fluctuating velocity of a particle is modeled by a simplified Langevin equation and the particle turbulence frequency is represented by the modified Jayesh - Pope model. Effects of molecular diffusion are represented by the interaction by exchange with the mean (IEM) mixing model. To validate this hybrid FV/PDF transport model, the numerical results are compared with experimental data for the turbulent bluff-body reacting flows.