• 제목/요약/키워드: Multiple Jet Flame

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다수 상호작용 화염의 공해배출물 특성 (Effect of Flame Interaction on the NO Emission)

  • 김진현;이병준
    • 대한기계학회논문집B
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    • 제29권6호
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    • pp.730-736
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    • 2005
  • It has been reported that the interacting multiple jet flames of propane fuel are not extinguished even at the choking velocity at the nozzle exit if eight small nozzles are arranged along the imaginary circle of $40{\sim}72$ times the diameter of single nozzle. In this research, experiments were conducted to know the NO and CO emission characteristics of the interacting flames. Measurements along the centerline of the flame revealed that decrease in CO concentration was followed by the NO decrease and $O_2$ increase. It was found that interacting flame emitted less NO than that of similar area single jet flame. Also, NO emission of partially premixed interacting flame was decreased up to $17\%$ of that of non-premixed multiple jet flame. Though the mechanism of the NO reduction was not clear from this experiment, it's been shown that partially premixed multiple jet flames could be used to achieve clean and highly stable combustion.

난류분무제트연소에서의 화염구조와 조건평균 통계에 대한 수치적 연구 (Numerical Study of Flame Structures and Conditional Statistics in Turbulent Spray Jet Combustion)

  • 서재엽;허강열
    • 한국연소학회지
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    • 제17권3호
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    • pp.46-52
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    • 2012
  • 3D DNS is performed for n-heptane spray turbulent jet combustion. Diesel-like conditions are considered including single and multiple injections. Conditional statistics are obtained for multiple Lagrangian flame groups of sequentially evaporating fuel. Each fuel group represents the conditional statistics of an independent Lagrangian flame group. Sequentially evaporating fuel goes through different histories and residence times over the ignition delay period. Multiple flame groups are required for accurate description of combustion of a spray jet that goes through a long injection duration or multiple injections.

메탄 비예혼합 상호작용 화염의 특성 (Characteristics of Methane Non-Premixed Multiple Jet Flames)

  • 김진현;이병준
    • 대한기계학회논문집B
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    • 제29권3호
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    • pp.349-355
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    • 2005
  • It has been reported that propane non-premixed interacting flames are not extinguished even in 210m/s if eight small nozzles are arranged along the imaginary circle of 40 ~ 72 times the diameter of single nozzle. In this research, experiments were extended to the methane flame. Nine nozzles were used- eight was evenly located along the perimeter of the imaginary circle and one at the geometric center. The space between nozzles, s, the exit velocity and the role of the jet from the center nozzle were considered. On the contrary to the propane non-premixed flame, small amount of fuel fed through the center nozzle makes the methane diffusion flame stable even at the choking conditions. In the laminar region, the flame at the center nozzle anchored the outer lifted flames.

메탄 비예혼합 상호작용 화염의 특성 (Characteristics of methane non-premixed multiple jet flames)

  • 이병준;김진현
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 추계학술대회
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    • pp.1365-1370
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    • 2004
  • It has been reported that if eight small nozzles are arranged along the circle of 40 $^{\sim}$ 72 times the diameter of single nozzle, the propane non-premixed flames are not extinguished even in 200m/s, In this research, experiments were extended to the methane flame. Nine nozzles were used- eight was evenly located along the perimeter of the imaginary circle and one at the geometric center. The space between nozzles, s, the exit velocity and the role of the jet from the center nozzle were considered. On the contrary to the propane non-premixed case, the maximum blowout velocity for the methane diffusion flame was achieved when small amount of fuel is supplied through the center nozzle and s/d equals around 21. In the laminar region, the flame attached at the center nozzle anchored the outer lifted flames.

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과농-희박연료가 교차로 공급되는 상호작용 화염의 화염날림에 관한 연구 (Effect of Lean-rich Fuel Staging to the Multiple Jet Flames on the Blowout Velocity)

  • 이병준;박경욱
    • 대한기계학회논문집B
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    • 제32권1호
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    • pp.7-14
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    • 2008
  • It has been reported that partially premixed interacting flame could be sustained till sonic exit velocities if eight small nozzles are arranged optimally and one nozzle on the center is fed small amount of fuel. But the equivalence ratios in this experiments were 20-60. In this research, experiments were conducted to know the effects of lean-rich staging in multiple jet flames on the blowout velocity. The fuel mole tractions in the fuel-air mixture, the nozzle exit velocity and the diameter between adjacent nozzles were alternatively changed. When the lower mole fraction fuel was fed to the nozzles located near the center and small amount of fuel to the center nozzle, flame was not extinguished even at the nozzle exit velocity of 200m/s. Also the interacting flame could be sustained till that velocity when four small size nozzles for lean mixture were located within the arrangement of four nozzles for rich mixture and configured optimally.

스월이 부분예혼합 상호작용화염의 화염날림 유속에 미치는 영향 (The Effect of Swirl on the Blowout Velocities of Partially Premixed Interacting Flames)

  • 이병준;최광덕
    • 한국연소학회지
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    • 제14권2호
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    • pp.26-31
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    • 2009
  • Adding small amounts of air to the fuel is used in many commercial combustors to avoid sooty flame. But partially premixed jet flame has lower blowout velocity, $u_{b.o}$, than nonpremixed one. Increasing blowout limit would be one of the key factors to develope highly intense compact combustion devices. Swirling flow enhances fuel and air mixing and induces a highly turbulent recirculation zone, which helps flame stabilization. It was known that NOx emission decreases with swirl on the proper range of swirl number. And it was shown that the flame interaction in multiple jets also increases $u_{b.o}$ owing to the internal recirculation and reduces NO emission. If the effects of swirl and flame interaction are combined together in partially premixed flame, both $u_{b.o}$ increasement and NOx emission reduction could be achieved. Blowout limits of partially premixed interacting propane flame in the swirling air coflow are investigated experimentally. The results show that the flame is not extinguished up to the experimental limits, 210 m/s, at the swirl number of 0.32 and $X_{F,o}$ = 0.46.

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석탄가스 선회난류 비예혼합 화염장의 화염구조 및 NOx 배출특성 해석 (Numerical Study on Structure and Pollutant Formation for Syngas Turbulent Nonpremixed Swirling Flames)

  • 이정원;강성모;김용모;주용진
    • 한국연소학회지
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    • 제14권2호
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    • pp.10-17
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    • 2009
  • The present study numerically investigate the effects of the Syngas chemical kinetics on the basic flame properties and the structure of the Syngas nonpremixed flames. In order to realistically represent the turbulencechemistry interaction and the spatial inhomogeneity of scalar dissipation rate, the Eulerian Particle Flamelet Model (EPFM) with multiple flamelets has been applied to simulate the combustion processes and NOx formation in the syngas turbulent nonpremixed flames. Validation cases include the Syngas turbulent nonpremixed jet and swirling flames. Based on numerical results, the detailed discussion has been made for the effects of the chemical kinetics, the flame structure, and NOx formation characteristics in the turbulent Syngas nonpremixed flames.

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메탄/공기 다중 제트 예혼합 화염에서의 유동과 연소특성 (Flow and Combustion Characteristic in an Array of Multiple Pre-Mixed Methane/Air Flame Jets)

  • 김영수;이대래;하만영;장영준;전충환;조승완;강길영;유재현
    • 대한기계학회논문집B
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    • 제31권6호
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    • pp.547-557
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    • 2007
  • This study was conducted to investigate the flow and combustion characteristic of the experimental burner which was manufactured for the reflection of the oven and broil burner features. As slot shape, spacing between slots, and slot arrangement of the exit area which emits the mixing gas are different in case of oven burners and broil turners, the purpose of this study is to know the affection of the flame interaction and combustion characteristic according to the change of shape factors such as slot shape, slot arrangement, and slot-to-slot spacing. With no relation of the slot shape, as the spacing between slots became narrow, the occurrence of a lift-flame was delayed. So the combustion was possible in the leaner region, but the appearance of yellow-tip became a little fast. Slit slot port had the broadest operating range among the other slot shapes. Specially, from the side of lift-flame, as the jet that spreads downstream in the longitudinal slot was nearly circular just a few slot lengths away from the orifice, slot-to-slot spacing of the Slit port was closer than the other ports. These results could be expected through the computer numerical method and had a good agreement. As the spacing between slots increased, in case of Slit and Mix port, NOx emission rate was constant or decreased, but the NOx emission of Hole port was increased. CO emission rate of Slit and Hole port was increased as the slot-to-slot spacing was broadened.

석탄가스 선회난류 연소기의 화염구조 및 공해물질 배출특성 해석 (Numerical Study on Flame Structure and Pollutant Formation for Syngas Turbulent Nonpremixed Swirl Burner)

  • 이정원;강성모;김용모
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2007년도 추계학술대회 논문집
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    • pp.449-452
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    • 2007
  • The present study numerically investigate the effects of the Syngas chemical kinetics on the basic flame properties and the structure of the Syngas diffusion flames. In order to realistically represent the turbulence-chemistry interact ion and the spatial inhomogeneity of scalar dissipation rate. the Eulerian Particle Flamelet Model(EPFM) with multiple flamelets has been applied to simulate the combustion processes and NOx formation in the syngas turbulent nonpremixed flames. Due to the ability for interactively describing the transient behaviors of local flame structures with CFD solver, the EPFM model can effectively account for the detailed mechanisms of NOx format ion including thermal NO path, prompt and nitrous NOx format ion, and reburning process by hydrocarbon radical without any ad-hoc procedure. validation cases include the Syngas turbulent nonpremixed jet and swirling flames. Based on numerical results, the detailed discussion has been made for the sensitivity of the Syngas chemical kinetics as well as the precise structure and NOx formation characteristics of the turbulent Syngas nonpremixed flames.

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