• 제목/요약/키워드: Turbulent Diffusion Flame

검색결과 122건 처리시간 0.023초

송풍기와 폐풍기를 이용한 연소기내의 부분 예혼합화염 연소 특성에 관한 실험적 연구 (Experimental Investigation on premixed combustion Characteristics with suction & blow fans)

  • 강기발;오상헌
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 추계학술대회논문집B
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    • pp.143-148
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    • 2001
  • We measured emission indices for $NO_x$, CO, temperature and radical characteristics for partially premixied flames formed by suction & blow fans air condition. At sufficiently high levels of partial premixing a double flame structure consisting of a rich premixed inner flame and outer diffusion flame was established similar to that previously observed in premixed flames. $NO_x$, Temperature, CO values were experimented with approximately constant air flow rate and decreasing equivalence ratios. The reduction in $NO_x$ and temperature at suction condition as compared with that for blow condition was approximately 20%, but on the contrary, CO emission was increased. In addition, We measured temperature distributions and found that temperature increased continuously with increasing partial premixing. We also estimated CH, $C_2$ radical intensity. CH and $C_2$ radicals provide evidence that, for the present measurement, CH and $C_2$ radicals intensity was associsated with their premixed component. And we observed stronger $C_2$, CH radicals intensity at suction conditions than blow conditions.

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Suction과 blow fan을 이용한 연소기내의 부분 예혼합화염 연소 특성에 관한 실험적 연구 (Experimental Investigation on Premixed Combustion Characteristics with Suction & Blow Fans)

  • 강기발;김동일;오상헌
    • 한국연소학회지
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    • 제7권2호
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    • pp.15-23
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    • 2002
  • We measured emission indices for $NO_x$, CO, temperature and radical characteristics for partially premixied flames formed by suction & blow fans air condition. At sufficiently high levels of partial premixing a double flame structure consisting of a rich premixed inner flame and outer diffusion flame was established similar to that previously observed in premixed flames. $NO_x$, Temperature. CO concentration were experimented with approximately constant air flow rate and decreasing equivalence ratios. The reduction in $NO_x$, and temperature at suction condition as compared with that for blow condition was approximately 20%, but on the contrary, CO emission was increased. In addition, We measured temperature distributions and found that temperature increased continuously with increasing partial premixing. We also estimated CH, $C_2$ radical intensity. CH and $C_2$ radicals provide evidence that, for the present measurement, CH and $C_2$ radicals intensity was associsated with their premixed component. And we observed stronger $C_2$, CH radicals intensity at suction conditions than blow conditions.

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부상된 동축공기 수소 난류확산화염에서의 화염안정화 특성 (Characteristics of Stabilization Point in Lifted Turbulent Hydrogen Diffusion Jet with Coaxial Air)

  • 오정석;김문기;윤영빈
    • 한국항공우주학회지
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    • 제36권4호
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    • pp.352-356
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    • 2008
  • 수소제트와 동축공기를 사용한 본 연구에서, 난류확산화염의 화염안정성 특징을 실험적으로 수행하였다. 목적은 연료속도 증가에 따라 감소하는 부상화염길이의 경향을 보고하고, 부상 메커니즘을 포함한 화염구조를 분석하는 것이다. 수소연료는 100에서 300 m/s 사이에서 조절되었으며, 이때 동축공기는 16 m/s 고정되고, 주위류는 0.1 m/s 이하로 유지되었다. 유동장과 연소장 동시측정을 위하여, 두 대의 Nd:Yag 레이저와 CCD 카메라를 이용하여 PIV와 OH PLIF 기법이 사용되었다. 결론적으로 난류화염전파속도는 난류강도에 비례하였으며, 제트 레이놀즈수의 0.017승에 비례하였다.

음향 가진 된 프로판 확산 화염의 부상 거동에 관한 실험적 연구 (Experimental Study on the Lift-off Behavior of Tone-excited Propane Jet Diffusion flames)

  • 김승곤;박정;김태권;이기만
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 제26회 KOSCO SYMPOSIUM 논문집
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    • pp.65-73
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    • 2003
  • An experimental study on flame lift-off characteristics of propane jet flame highly diluted with nitrogen has been conducted introducing acoustic forcing with a tube resonant frequency. A flame stability curve is attained according to forcing strength and nozzle exit velocity for $N_2$ diluted flames. Flame lift-off behavior with forcing strength and nozzle exit velocity is globally categorized into three; a well premixed behavior caused by a collapsible mixing for large forcing strength, a coexistent behavior of well-premixed and edge flames interacting with well-organized inner fuel vortices for moderate forcing strengths, and edge flame behavior for small forcing strengths. Special focus is concentrated on the coexistent behavior of the flame base in lifted flame since this may give a hint to a possibility which the flame base behaves like a well-mixed premixed flame in highly turbulent lifted flames. It is also shown that the acoustic forcing to self-pulsating laminar lifted flame affects flame lift-off behavior considerably which is closely related to downstream flow velocity, mixture strength, effective fuel Lewis number, and flame stretch.

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재순환 영역이 있는 축대칭 난류 확산화염의 구조 (II) (The Structure of Axisymmeric Turbulent Diffusion Flame(II))

  • 이병무;신현동
    • 대한기계학회논문집
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    • 제10권1호
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    • pp.70-77
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    • 1986
  • 본 논문에서는 재순환 영역이 존재하는 축대칭 난류 확산화염 구조예측의 전 단계로서, 이미 발표된 바있는 필자의 실험 데이터를 바탕으로 하여 등온유동에 서의 난류모델을 검토한다. 유선의 곡률이 큰 유동에 2방정식 모델을 적용함은 큰 결점을 보완한 수정-2방정식모델을 채택하여 실험결과와 비교, 검토하여 모델의 타당성을 조사하였다.

희박연소 및 EGR 엔진에서 초기 화염액 생성 및 성장에 관한 연구 (A Study on the Kernel Formation & Development for Lean Burn and EGR Engine)

  • 송정훈;선우명호
    • 한국자동차공학회논문집
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    • 제7권8호
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    • pp.24-33
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    • 1999
  • This paper investigate the effects of the variations of engine operation condition in the flame kernel formation and developmnet . A model for calculating the initial kernel development in spark ignition engines is formualted. It considered input of electrical energy, combustion energy release and heat transfer to the spark plyg, cylinder head, and unburned mixture. The model also takes into accounts strain rate of initial kernel and residual gas fraction. The breakdown process and the subsequent electrical power input initially control the kernel growth while intermediate growth is mainly dominated by diffusion or conduction. Then, the flame propagates by the chemical energy and turbulent flame expansion. Flame kernel development also influenced by engine operating conditions, for example, EGR rate, air-fuel ration and intake manifold pressure.

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프로판 동축류 확산 화염에서 화염 부상과 재부착에 관한 실험적 연구 (An Experimental Study on Liftoff and Reattachment Characteristics in Concentric Burner)

  • 박성호;원상희;차민석;정석호
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2001년도 제23회 KOSCO SYMPOSIUM 논문집
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    • pp.119-124
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    • 2001
  • Propane coflow diffusion flames have been experimentally studied to investigate the liftoff and reattachment characteristics. Flame properties such as velocity and density distribution were measured by LDV and shadowgraphy, respectively. It is shown that as the velocity of coflowing air increases, liftoff velocity decreases nonlinearly in turbulent jets and linearly in laminar jets, while reattachment velocity decreases nonlinearly. Meanwhile, as inner nozzle tip thickness increases, liftoff velocity increases with the reattachment velocity nearly unchanged. Liftoff phenomena in these flames can be categorized into three classes as a function of coflow velocity, such as laminar liftoff, turbulent liftoff, and transient liftoff.

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고온공기를 이용한 제트확산화염의 연소특성에 관한 실험 (Experiment on the Characteristics of Jet Diffusion Flames with High Temperature Air Combustion)

  • 조은성;대야건;소림수소;정석호
    • 대한기계학회논문집B
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    • 제28권3호
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    • pp.359-364
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    • 2004
  • For the development of high efficiency and low emission combustion systems, high temperature air combustion technology has been tested by utilizing preheated air over 1100 K and exhaust gas recirculation. In this system, combustion air is diluted with large amount of recirculated exhaust gases, such that the oxygen concentration is relatively low in the reaction zone, leading to low flame temperature. Since, the temperature fluctuations and sound emissions from the flame are small and flame luminosity is low, the combustion mode is expected to be flameless or mild combustion. Experiment was performed to investigate the turbulent flame structure and NO$_x$ emission characteristics in the high temperature air combustion focused on coflowing jet diffusion flames which has a fundamental structure of many practical combustion systems. The effect of turbulence has also been evaluated by installing perforated plate in the oxidizer inlet nozzle. LPG was used as a fuel. Results showed that even though NO$_x$ emission is sensitive to the combustion air temperature, the present high temperature air combustion system produce low NO$_x$ emission because it is operated in low oxygen concentration condition by the high exhaust gas recirculation.

제트확산염의 고온공기연소특성에 관한 실험적 연구 (An Experimental Study of the Characteristics with High Temperature Air Combustion in Jet Diffusion Flames)

  • 조은성;대야건;소림수소;정석호
    • 한국연소학회:학술대회논문집
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    • 대한연소학회 2003년도 제27회 KOSCO SYMPOSIUM 논문집
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    • pp.89-94
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    • 2003
  • For the development of high efficiency and low emission combustion systems, high temperature air combustion technology has been tested by utilizing preheated air over 1100 K and exhaust gas recirculation. In this system, combustion air is diluted with large amount of exhaust gases ($N_2$, $CO_2$), such that the oxygen concentration is relatively low in the reaction zone, leading to low flame temperature. Since, the temperature fluctuations and sound emissions form the flame are small and flame luminosity is low, the combustion mode is expected to be flameless or mild combustion. Experiment was performed to investigate the turbulent flame structure and $NO_X$ emission characteristics in the high temperature air combustion focused on coflowing jet diffusion flames which has a fundamental structure of many practical combustion systems. The effect of turbulence has also been evaluated by installing perforated plate in the oxidizer inlet nozzle. LPG was used as a fuel. Results showed that even though $NO_X$ emission is sensitive to the combustion air temperature, the present high temperature air combustion system produce low $NO_X$ emission because it is operated in low oxygen concentration condition in excess of dilution.

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시험용 연소로에서의 다단 저 NOx 버너의 실험 및 수치적 연구 (Experimental and Numerical Study of Low NOx Multi-Staged Burner in the Test Combustor)

  • 최윤기;강경태;임기석;고동완;김용모
    • 대한기계학회논문집B
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    • 제28권11호
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    • pp.1339-1347
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    • 2004
  • Development of the low NOx heating boiler was strongly asked due to severe air pollution and the large number of boilers in korea. Compactness of the commercial boiler was also important because of low manufacturing cost and easy installation. In this study. newly developed compact low NOx burner, using turbulent gas diffusion combustion with multi-staged air supplies and multiple fuel nozzles, was investigated. Comparison study of the new burner was performed between experimental results and computational analysis. Commercial computational fluid dynamic(CFD) program named CFX-5.6 was used for numerical analysis of the low NOx burner inside the test combustor. Comparisons of experiment data and numerical result were performed under various equivalence ratio and fuel flow rate.