• 한국연소학회:학술대회논문집
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• 2003.05a
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• pp.223-227
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• 2003

The method of flame hole dynamics is demonstrated as a mean to simulate turbulent flame extinction. The core of the flame hole dynamics involves derivation of a random walk mapping for the flame holes, created by local quenching, between the burning and quenched states provided that the dynamic characteristics of flame edges is known. Then, the random walk mapping is projected to a background turbulent field. The numerical simulations are carried out with the further simplifications of flame string and unconditioned scalar dissipation rate. The simulation results show how the chance of partial quenching is influenced by the crossover scalar dissipation rate. Finally, a list of improvements, necessary to achieve more realistic turbulent flame quenching simulation, are discussed.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.198.2-198.2
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• 2010

Three dimensional numerical analysis of the oxygen and air were performed to investigate the combustion characteristics in a Corner-type pulverized coal boiler. With the actual operation data of the power plant, the distribution of velocity, gas temperature, $O^2$, $CO_2$, $H_2O$, $N_2$ as well as the particle tracking in the boiler were investigated. The predicted values at the outlet of furnace for the gas temperature and major species concentrations gave a good agreement with the designed values. The present analysis on combustion characteristics in a boiler would provide the useful information for the stable boiler operation and in trouble shooting boiler problem.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1374-1375
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• 2011

Mixed combustion expert system is implemented to prevent various problems in combustion process by increasing rate of mixing low calorific value coal to reduce costs. This system shows optimal coal mixture rate by interfacing CBS(Coal Blending Screener, Implementing slagging and fouling factors by coal characteristic and algorithm), SGE(Stream Generate Expert, Combustion process model) and CFS(Configured Fireside Simulator, Computational fluid dynamics).

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.8
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• pp.849-854
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• 2005

The laminar flame concept in turbulent reacting flow is considered applicable to many practical combustion systems For turbulent premixed combustion under widely used flamelet concept, the flame surface is described as an infinitely thin propagating surface that such a Propagating front can be represented as a level contour of a continuous function G. In this study, for the Purpose of validating the LES of G-equation combustion model. LES of turbulent Premixed combustion with dynamic SGS model of G-equation in turbulent channel flow are carried out A constant density assumption is used. The Predicted flame propagating speed is goof agreement with the DNS result of G. Bruneaux et al.

• 한국연소학회:학술대회논문집
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• 2007.05a
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• pp.92-97
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• 2007

Numerical simulations were carried out to investigate the base drag characteristics of a base bleed projectile with a central propulsive jet by considering the base burning process. Overall fluid dynamic process is modeled by Navier-Stokes equations for reacting flows with two-equation $k-{\omega}$ SST turbulence closure. The combustion process is modeled by finite-rate chemistry with a given partially burned exit condition of the BBU (base-bleed unit). Besides the demonstrating the capability of the present CFD solver for the base drag and the interaction of the base flow with a rocket plume, present study gives an insight into the fluid dynamics and the combustion process of the hybrid-propulsion projectile.

• Journal of ILASS-Korea
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• v.2 no.1
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• pp.18-28
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• 1997

The present study is mainly aiming at numerically analyzing the combustion and emission characteristics of the diesel spray in a high-pressure environment. Computations are peformed for the peak chamber pressure with range from 4.08 MPa to 162 MPa. Numerical results indicate that the pressure increase in combustion chamber significantly influences the mechanism for droplet dynamics and mixing characteristics, spray penetration autoignition, flame lift-on height and the propagation or fuel vapor and flame. By increasing the ratio or the ambient density to injected liquid density, the fuel-air mixing rates and the burning rates increase and the $NO_x/soot$ emission level decreases.

• Journal of ILASS-Korea
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• v.1 no.4
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• pp.40-45
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• 1996

This Paper addresses to spray characteristics in w-shaped diesel engine combustion chamber which has impingement parts for 4 sprays injected from an injector. The two-dimensional shapes have been chosen to avoid the difficulties for analysing the spray dynamics in the real chamber. The simple shapes are reproduced with same geometries in vertical or horizontal sections through the impingement lands. The spray developments are visualized with a high speed drum camera and shadowgraphy optical system, and the droplet sizes are measured by Malvern system. The detailed discussions m made for the two different combustion chamber shapes, which are new w-shape using spray wall impaction and general w-shape. The results show that the spray characteristics of the new shape are superior to those of the general w-shape.

• Journal of ILASS-Korea
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• v.21 no.2
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• pp.104-110
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• 2016

Main purpose of the current paper is to show results of time lag analysis using phase information of flame transfer function in order to predict combustion instabilities in a gas turbine combustor. The flame transfer function (FTF) is modeled using a commercial Computational Fluid Dynamics (CFD) code (Fluent). Comparisons of the modeled flame shapes with the measured ones were made using the optimized heat transfer conditions and combustion models. The FTF modeling results show a quite good agreement with the measurement data in predicting the phase delay (i.e. time lag). Time lag analysis results using the phase of FTF shows better combustion instability prediction accuracy than using time lag calculated from the steady state flame length.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.3
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• pp.354-362
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• 2000

This paper identifies a discrete-time linear combustion model of Refuse Incineration Plant(RIP) which characterizes steam generation quantity, where the RIP is considered as a MIMO system with thirteen-inputs and one-output. The structure of RIP model is described as an ARX model which are analytically obtained from the combustion dynamics. Furthermore, using the Instrumental Variable(IV) identification algorithm, model structure and unknown parameters are identified from experimental input-output data sets, In result, it is shown that the identified ARX model well approximates the input-output combustion characteristics given by experimental data sets.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.5
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• pp.86-95
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• 2000

A modified spray impingement model has been developed, which is assessed against experiments for the impinging sprays on the small combustion chamber at various gas pressures. To investigate spray behaviors in the diesel combustion chamber, a transparent constant-volume chamber is made which is similar to the combustion chamber of the real diesel engine. The chamber is pressurized by N2 gas from 0 bar to 20 bar to find the effects of ambient pressures. The behaviors of spray injected into this chamber and dispersed after impingement on the cylinder wall is measured two-dimensionally using laser sheet Mie scattering method. The physical submodels have been properly modified to improve the prediction capability of original KIVA code to describe the spray behaviors after impingement on the curved cylinder wall. In terms of spray dynamics and evolution. numerical results give qualitatively good agreements with experimental data.