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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Society of Combustion
Journal Basic Information
Journal DOI :
The Korean Society of Combustion
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Volume & Issues
Volume 3, Issue 2 - Dec 1998
Volume 3, Issue 1 - Jun 1998
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A Study on Blend Effect of Fuel in Flame Spread Along An One-Dimensional Droplet Array
Park, Jeong ; Kobayashi, Hideaki ; Niioka, Takashi ;
Journal of the Korean Society of Combustion, volume 3, issue 2, 1998, Pages 1~11
Experimental investigation on flame spread of blended fuel droplet arrays has been conducted for droplet diameters of 1.0mm and 0.75mm using high-speed chemiluminescence images of OH radical. The flame spread rate is measured with blended fuel composition, droplet diameter, and droplet spacing. Flame spread is categorized into two: a continuous mode and an intermittent one. There exist a limit droplet spacing, above which flame does not spread, and a droplet spacing of maximum flame spread, which is closely related to flame diameter. It is seen that flame spread rate is mainly dependent upon the relative position of flame zone within a droplet spacing. In case of large droplet, the increase of % volume of Heptane induces the shift of limit droplet spacing to a larger spacing since volatile Heptane plays a role of an enhancer of flame spread rate. In case of small droplet, the increase of % volume of Heptane leads to the shift of limit droplet spacing to a smaller droplet spacing. This is so because of the delayed chemical reaction time by the rapid increase of mass flux of fuel vapor for small droplet.
The Effects of Injector and Swirler on the Flame Stability in a Model Combustor
Park, Seung-Hun ; Lee, Dong-Hun ; Bae, Choong-Sik ;
Journal of the Korean Society of Combustion, volume 3, issue 2, 1998, Pages 13~27
The optimization of frontal device including fuel nozzle and swirler is required to secure the mixing of fuel and air and the combustion stability leading the reduction of pollutant emissions and the increase of combustion efficiency in gas turbine combustor. The effects of injection nozzle and swirler on the flow field, spray characteristics and consequently the combustion stability, were experimentally investigated by measuring the velocity field, droplet sizes of fuel spray, lean combustion limit and the temperature field in the main combustion region. Flow fields and spray characteristics were measured with APV(Adaptive Phase Doppler Velocimetry) under atmospheric condition using kerosine fuel. Temperatures were measured by Pt-Pt13%Rh, R-type thermocouple which was 0.2mm thick. Spray and flame was visualized by ICCD(Intensified Charge Coupled Device) camera. It was found that the dual swirler resulted in the biggest recirculation zone with the highest reverse flow velocity at the central region, which lead the most stable combustion. The various combustion characteristics were observed as a function of the geometries of injector and swirler, that gave a tip for the better design of gas turbine combustor.
A Study on Structures and NOx Formation Characteristics in Coflow and Counterflow Diffusion Flamelet
Oh, C.B. ; Kim, J.S. ; Lee, C.E. ; Lee, K.M. ;
Journal of the Korean Society of Combustion, volume 3, issue 2, 1998, Pages 29~40
Flame structures and NOx formation characteristics in the flame lets of coflow and counterflow diffusion flame are numerically studied. Calculations were carried out twice with the
Mechanism for each flame. Mixture fractions and scalar dissipation rates are used as the parameters to compare the flame let structures and NOx formation characteristics quantitatively. It was found that there is a similarity in flame temperature and stable species profiles except radical profiles between two flamelets. And there are some differences in NOx concentration and production rates. These results imply that the flow effects must be considered in calculations for NOx formation of turbulent flames using Laminar Flamelet Model.
The Influence of
Counterflow Nonpremixed Flames
Lee, Ki-Yong ;
Journal of the Korean Society of Combustion, volume 3, issue 2, 1998, Pages 41~50
Numerical simulations of nonpremixed
(Trichloroethylene, TCE)/Air flames are conducted at atmospheric pressure in order to understand the effect of hydrocabon bound chlorine on methane/air flames. A chemical kinetic mechanism is employed, the adopted scheme involving 48 gas-phase species and 445 elementray reaction steps containing 223 backward reactions. The calculated temperature, velocity, and critical strain rate are compared with the experiments for the flame (16.1% TCE by Vol.) estabilished at a strain rate of
. Whereas there is overall good agreement between predictions and the measurements, it appears that the critical strain rate is higher than measured, and some areas of further refinement in the kinetic mechanism are required.
Experimental and Numerical Study on Characteristics of Air-assisted Spray and Spray Flames
Kim, Dong-Il ; Oh, Sang-Huen ;
Journal of the Korean Society of Combustion, volume 3, issue 2, 1998, Pages 51~63
Air-assisted atomizer flames are investigated numerically to study spray structures in nonburning and burning conditions based on experimental data. A PDA is used to measure droplet size, velocity, and number density for both nonburning and burning spray. Computations utilize time-averaged gas-phase equations and
turbulence model for simplicity. The major features of the liquid-phase model are that a SSF approach is used to represent the effect of gas-phase turbulence on droplet trajectories and vaporization, an infinite-diffusion model is employed to represent the transient liquid-phase process. Computation and experiment results show that the droplet acceleration and evaporation proceed quickly in near the atomizer, characterizing high number densities and a strong convective effect. The primary combustion zone, however, is dorminated by the gas phase reaction and exhibits a sheath combustion.