• Title/Summary/Keyword: 최연소

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An Experimental Study for Performance Evaluation of a Ceramic Heat Exchanger (세라믹 열교환기의 성능평가를 위한 실험적 연구)

  • Choi, Hyun-Soo;Shin, Dong-Hoon
    • Journal of the Korean Society of Combustion
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    • v.16 no.1
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    • pp.46-51
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    • 2011
  • Exhaust gas of an industrial furnace used at such as metallurgy or ceramic manufacturing usually contains thermal energy with high temperature which can be recycled by heat exchanger. However, when the temperature of the exhaust gas is high such as more than $1,000^{\circ}C$, ordinary metallic heat exchanger cannot fully recover the heat due to the limitation of operating temperature depending on the material property. In the present study, a compact ceramic heat exchanger of cross flow type is introduced and evaluated by heat exchange rate and operating temperature. The ceramic heat exchanger can endure the gas temperature more than $1,300^{\circ}C$, and its volumetric heat exchanging rate exceeds 1 MW/$m^3$. The experimental data is also compared with the previous numerical result which shows reasonable agreement. Meanwhile, the gas leakage rate is measured to be about 3~4%, and heat loss to environmental air is about 23~26% of the fuel energy.

Partial Preconditioning Approach for the Solution of Detailed Kinetics Problems Based on Sensitivity Analysis (효율적인 상세 반응 기구 해석을 위한 민감도 기반의 부분 음해법)

  • Kang, K.H.;Moon, S.Y.;Noh, J.H.;Won, S.H.;Choi, J.Y.
    • Journal of the Korean Society of Combustion
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    • v.13 no.1
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    • pp.17-22
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    • 2008
  • A partly implicit/quasi-explicit method is introduced for the solution of detailed chemical kinetics with stiff source terms based on the standard fourth-order Runge-Kutta scheme. Present method solves implicitly only the stiff reaction rate equations, whereas the others explicitly. The stiff equations are selected based on the survey of the chemical Jaconian matrix and its Eigenvalues. As an application of the present method constant pressure combustion was analyzed by a detailed mechanism of hydrogen-air combustion with NOx chemistry. The sensitivity analysis reveals that only the 4 species in NOx chemistry has strong stiffness and should be solved implicitly among the 13 species. The implicit solution of the 4 species successfully predicts the entire process with same accuracy and efficiency at half the price.

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Numerical Study of Three Dimensional Detonation Waves Structure in Highly Unstable Mode. (고불안정 조건에서의 3차원 데토네이션 파면 구조 해석 연구)

  • Cho, Deok-Rae;Won, Su-Hee;Shin, Jae-Ryul;Choi, Jeong-Yeol
    • 한국연소학회:학술대회논문집
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    • 2012.11a
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    • pp.359-362
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    • 2012
  • The results are shown highly unstable mode's detonation dynamics by compared with weakly unstable mode. And we investigate the difference and similar features of 2D and 3D results. By using PSD via FFT, the effects of pre-exponential factor difference and of unstable mode were investigated in this study. The result of PSD is shown pulsed features in weakly unstable mode, but noselike in highly unstable mode. By compared between Sheliren image and overlaid slice image, the irregular feature of detonation waves structure was discussed in highly unstable mode.

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Study on Pneumatic Transport for Pulverized coal Combustion (미분탄 연소를 위한 공기압 수송에 관한 연구)

  • Oh, C.S.;Choi, B.S.;Hong, S.S.;Hwang, K.S.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.4 no.4
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    • pp.299-305
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    • 1992
  • Saltation occurs in horizontal flow of solid and gas when the carrier gas velocity is small enough to permit enough to settling of the solid particles within the transport line. So we should examine the pneumatic flow system to lessen the unbured carbon in the power plant. In this paper the saltation velocity was studied on the various solid flow rate in the constant pipe diameter and on the various temperatures of the flow gas. The air velocity in the power plant transport lines was also surveyed in order to compare with the saltation velocity. As the solid flow rate increased in the constant diameter, saltation velocity increased and as the temperater of the flow gas inereased in the transport line, saltation velocity also increased.

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A Case Study of the Sungnyemun Fire for Identification (숭례문 화재의 감식 사례 연구)

  • Choi, S.B.;Lee, J.J.;Lee, T.Y.;Lee, C.J.;Choi, D.M.
    • Proceedings of the Safety Management and Science Conference
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    • 2009.04a
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    • pp.1-6
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    • 2009
  • The fire of Sungnyemun, National Treasure of No.1, gave to the Korean people and fire investigators big pains. The aim of this study are the identification of combustion traces and fire patterns of wooden building fire, burned with an accelerator, after spraying flammable materials on the wooden floor through the field study observation. Also, in the case of the similar fire, these results will be as good references to fire investigators for accurate investigations.

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Mechanism of Combustion Instability in Supersonic Combustor (초음속 연소기 내의 연소 불안정 메커니즘)

  • 최정열
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2003.10a
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    • pp.191-194
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    • 2003
  • A series of computational simulations have been carried out for non-reacting and reacting flows in a supersonic combustor configuration with and without a cavity. Transverse injection of hydrogen, a simplest form of fuel supply, is considered in the present study with the injection pressure of 0.5 and 1.0 ㎫. The corresponding equivalence ratios are 0.17 and 0.33. The work features detailed resolution of the flow and flame dynamics in the combustor, which was not typically available in most of the previous studies. In particular, oscillatory flow characteristics are captured at a scale sufficient to identify the underlying physical mechanisms. Much of the flow unsteadiness is related not only to the cavity, but also to the intrinsic unsteadiness in the flowfield. The interactions between the unsteady flow and flame evolution may cause a large excursion of flow oscillation. The role of the cavity, injection pressure, and amount of heat addition are examined systematically.

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Research Activities of Dual-Mode Ramjet (DMR) by USAF and Dual-Combustion Ramjet (DCR) by US Navy (미 공군의 이중모드 램제트 (DMR) 및 미 해군의 이중연소 램제트 (DCR) 개발 동향)

  • Choi, J.Y.;Noh, J.;Won, S.H.;Shin, J.R.
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.05a
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    • pp.400-401
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    • 2009
  • Present paper introduces the concepts and R&D activities on the hypersonic vehicles, X-51A by USAF using Dual-Mode Ramjet (DMR) and HyFly by US Navy using Dual-Combustion Ramjet (DCR) both sponsored by DARPA.

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Measurments of 2-D Image Soot Distribution in Late Combustion Stage Using Elastic Scattering, Laser-Induced Incandescence and Flame Luminosity (레이저 탄성산란법, 여기적열법, 자발광을 이용한 가시화 디젤엔진의 후기연소의 2차원 soot 분포 측정)

  • Noh, S.M.;Won, Y.H.;Park, J.G.;Choi, I.Y.;Chun, K.M.
    • Proceedings of the KSME Conference
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    • 2000.11b
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    • pp.162-167
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    • 2000
  • Soot formation and oxidation is closely related to the combustion phenomena inside a diesel engine. Laser-based diagnostics provide a means for improving our understanding of diesel combustion, because they have highly temporal and spatial ability. To understand the soot behavior we did preliminary study by taking flame luminosity photographs and 2-D imaging soot distribution using Laser Elastic Scattering(LIS) and Laser-Induced Incandescence(LII). From the data we found that soot concentration was high in the bowl and disappeared from the central region in the late combustion stage.

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An Experimental Study on the Performance Characteristics of a Hydrogen Fueled LPi Engine (LPi기관에서 수소첨가에 따른 성능특성에 관한 실험적연구)

  • Choi, Gyeung Ho
    • Transactions of the Korean hydrogen and new energy society
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    • v.15 no.2
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    • pp.129-136
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    • 2004
  • 환경문제와 석유자원의 고갈이 많은 연구자들을 기존 탄화수소연료를 대체할수 있는 재생 가능한 연료를 구하는데 많은 노력을 기울이고 있다. 수소연료는 유해배기물질이 없는 연소와 또한 연소후에 재생 가능한 물성분만 배출하는 속성으로 미래의 청정에너지로 각광을 받고 있다. 이러한 이유로 수소연료는 수송기계의 연료로도 주목을 받고 있다. 따라서 수소연료기관 개발은 21세기에도 지속적으로 진행될 것이다. 이에대한 초기연구로 기체 LPG 연료가 아닌 액체 LPG 연료를 흡기관에 분사하여 기화된 LPG 연료를 엔진으로 흡입하는 LPi엔진에 수소연료를 과급하여 엔진에 성능을 연구하고자 하였다.

An Identification of Sungnyemun Fire as a Case Study (숭례문 화재감식 사례 연구)

  • Choi, S.B.;Lee, S.J.;Lee, S.H.;Choi, D.M.
    • Journal of Korean Institute of Fire Investigation
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    • v.11 no.1
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    • pp.74-82
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    • 2008
  • The fire of Sungnyemun, National Treasure of No.1, gave to the Korean people and fire investigators big pains. The aim of this study are the identification of combustion traces and fire patterns of wooden building fire, burned with an accelerator, after spraying flammable materials on the wooden floor through the field study observation. Also, in the case of the similar fire, these results will be as good references to fire investigators for accurate investigations.

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