• Title/Summary/Keyword: Flame Shape

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A Study on the Pollutant Reduction by Venturi Type After-burner (벤츄리형 후연소기의 오염물질 저감에 관한 연구)

  • Lee, Hwa-Sin;Lee, Yong-Hoo;Lee, Jin-Seok;Kwon, Oh-Boong;Lee, Do-Hyung
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2005.06a
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    • pp.81-86
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    • 2005
  • The purpose of this study is to develop venturi type after-burner in order to obtain pollutant reduction effect and find the best stable combustion condition. For this purpose, through a flow analysis, the shape of venturi type was made and flame holder locations were also decided by measuring chemical species at before and after the after-burner. Also, various chemical species concentration were measured at changing the induced air rates and the oxygen for oxygen enrichment for the solution the problems of much oxygen flow rate and the flame stability range. As results of this study, a flow distribution and the purification effect was excellent at venturi contraction 0.5 and flame holder location 12mm below the center of Venturi throat. On the purification characteristics, we found that pollutants reduction was effective when area ratio and oxygen are increased. But there are suitable quantities due to the flame shape change and combustion efficiency.

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The Physicochemical Properties of Hand-Peeled and Flame-Peeled Chestnuts (수작업 박피밤과 화염박피 밤의 물리화학적 특성)

  • 김종훈;박재복;최창현
    • Journal of Biosystems Engineering
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    • v.24 no.5
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    • pp.407-414
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    • 1999
  • To evaluate the quality of flame-peeled chestnuts, their physical and chemical properties were analyzed. The physicochemical properties of flame-peeled chestnuts, including geometrical shape, texture and chemical composition, were compared to those of hand-peeled ones. For the flame-peeled chestnuts, some properties in heated and non-heated sections were separately analyzed. The color, texture such as springness, cohesiveness, adhesiveness, hardness and chewiness, moisture content, and reducing sugar of the heated section of the flame-peeled chestnuts were significantly different with their non-heated section. But the physicochemical properties of the non-heated section of the flame-peeled chestnuts were similar to those of the hand-peeled ones.

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Pollutant Emission Characteristics of Double-Concentric Diffusion Flame (이중 확산 연소장에서의 오염물질 배출 특성)

  • 김종현;이근오;이창언
    • Journal of the Korean Society of Safety
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    • v.17 no.3
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    • pp.43-49
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    • 2002
  • The NOx emission characteristics of double-concentric diffusion flames and normal diffusion flames fueled with CH$_4$ were studied. Experimental and numerical investigations were carried out for double-concentric diffusion flame with varying central air flow rate and normal diffusion flame. The Emission indices of NOx(EINOx) were measured by chemiluminescent method and calculated by numerical model based on detailed chemistry. From the comparison between double-concentric diffusion flames and normal diffusion flames, the results show that EINOx of double-concentric diffusion flames are lower than normal diffusion flame, because of Prompt EINOx was decreased. EINOx of double-concentric diffusion flames increase with central air flow rate increasing.

A Study on the Flame Propagating Speed Measurement-For the Laminar Flame- (火焰傳播速度測定에 關한 硏究 -層流火焰에 關하여-)

  • 조경국;정인석;허원욱
    • Journal of the korean Society of Automotive Engineers
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    • v.1 no.1
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    • pp.28-41
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    • 1979
  • Propane-Air premixed combustible gas was ignited by the conventional current break system inside the open combustion chamber under the atmospheric pressure and the room temperature to measure the flame propagating speed and the burning speed, also to elucidate the history of the propagating flame behavior and wall effects to flame shape by using Ion Gap Method and High Speed Schlieren Photography. The results obtained show that the maximum flame propagating speed and maximum burning speed are approximately 292 cm/sec and 36 cm/sec at the mixture ratio 4.6%, respectively. The cellular flame structures can be observable in the rich mixture region, moreover, the cellular structures become finer, with increasing the mixture strength.

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Effects of an Ultrasonic Standing-wave Field on the Behavior of Methane/Air Premixed Flame (정상초음파장이 메탄/공기 예혼합화염의 거동에 미치는 영향)

  • Seo, Hang-Seok;Lee, Sang-Shin;Kim, Jeong-Soo;Lee, Do-Hyung
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2011.11a
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    • pp.303-306
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    • 2011
  • An experimental study has been conducted to investigate the effects of an ultrasonic standing-wave field to the behavior of methane/air premixed flame. Visualization technique utilizing the schlieren method was employed for the observation of premixed flame behavior. The shape of flame front and local flame velocity were measured according to the variation of reactants pressure and chamber opening/closing condition. The flame front was distorted and severely deformed to a lotus-type flame by the interaction of ultrasonic standing-wave and the reflection wave coming from an end wall of reactor.

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An Experimental Study on Flame Structure and Combustion Characteristics of Turbulent Diffusion Flame(II) (난류확산화염의 화염구조와 연소특성에 관한 실험적 연구(2))

  • Choe, Byeong-Ryun;Jang, In-Gap;Choe, Gyeong-Min
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.3
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    • pp.1050-1060
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    • 1996
  • Recently, attention has been paid to the flame diagnostic by noncontact methods which dose not deform the flame shape. One of them is a method which is using the radical luminous intensity. Generally, this diagnostic method using radical luminous has been investigated its reliability by applying to laminar flame. This study, however, investigated each radical luminous signals through stocastical analysis like auto-correlation, cross-correlation, phase and coherence which were acquired from measuring radical luminous intensity of OH, CH, $O_{2}$, radicals in turbulent diffusion flame. To compare radical luminous intensity in flame with temperature, ion current and concentration , radious distribution of each properties was investigated and considered. In radical luminous intensity, correlation in the reaction zone of flame was higher than in correlation in combusted gas zone. And radious distribution of radical luminous intensity was corresponded with radious distribution of temperature, ion current and concentration. The result of the study confirms that a radical luminous flame diagnosis is possible in the turbulent diffusion flame.

Buoyancy Effect on Stable and Oscillating Lifted Flames in Coflow Jets for Highly Diluted Propane (질소희석된 프로판 동축류 버너에서 부상화염에 대한 부력효과)

  • Kim, Jun-Hong;Shin, Moo-Kyung;Chung, Suk-Ho
    • 한국연소학회:학술대회논문집
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    • 2001.06a
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    • pp.9-16
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    • 2001
  • When large size nozzle with low jet velocity is used, the buoyancy effect arises from the density difference among propane, air, and burnt gas. Flame characteristics in such buoyant jets have been investigated numerically to elucidate the effect of buoyancy on lifted flames. It has been demonstrated that the cold jet has circular cone shape since upwardly injected propane jet decelerates and forms stagnation region. In contrast to the cold flow, the reacting flow with a lifted flame has no stagnation region by the buoyancy force induced from the burnt gas. To further illustrate the buoyancy effect on lifted flames, the reacting flow with buoyancy is compared with non-buoyant reacting flow. Non-buoyant flame is stabilized at much lower height than the buoyant flame. At a certain range of fuel jet velocities and fuel dilutions. an oscillating flame is demonstrated numerically showing that the height of flame base and tip vary during one cycle of oscillation. Under the same condition. non-buoyant flame exhibits only steady lifted flames. This confirms the buoyancy effect on the mechanism of lifted flame oscillation.

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The Effect of Particle Size on Combustion Characteristics of Pulverized High-Volatile Bituminous Coal

  • Kim, Hyung-Taek;Jeon, Heung-Shin;Wongee Chun
    • Journal of Energy Engineering
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    • v.6 no.2
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    • pp.162-169
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    • 1997
  • The particle size effect on the combustion characteristics of pulverized coal was investigated in the cylindrical-shape, horizontal furnace, fired in the range of 8.8∼10.6 kw. Three differently-sized fractions (5, 30, and 44 microns in average diameter) of high-volatile bituminous coal, were burned in the test furnace. Burnout behavior of pulverized coal flame were determined through the measurement of stable species concentrations (CO$_2$and H$_2$O). Concentrations of CO$_2$were compared with the theoretical values and the result showed good agreement. Thermal behavior of pulverized coal flame were determined as maximum flame temperatures occurred at fuel-rich conditions in every case. Flame lengths were also determined by decreasing with the particle size decrease. The flame length of the fine sized coal sample was comparable to that produced by distillate oil. The color of the coal flames ranged from orange to yellow, with the flame of the fine size fraction being brighter and yellower than the others.

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Influence of Inert Gas on the Configuration Characteristics of Premixed Turbulent Propagating Flames of Hydrogen Mixtures (수소 예혼합 난류전파화염의 화염형상 특성에 미치는 불활성 가스의 영향)

  • 나까하라마사야;키도히로유끼;김준효
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.4
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    • pp.632-640
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    • 2004
  • The purpose of this study is to clarify the influence of inert gas on the configuration characteristics of premixed turbulent propagating flames of hydrogen mixtures. Inert gas is changed to $N_2$, Ar, $CO_2$ and He keeping the laminar burning velocity of mixtures nearly the same value. A laser tomography technique was used to obtain the flame shape, and quantitative analyses were performed. The result shows that in the wrinkled laminar flame region, the surface area of turbulent flame is slightly dependent on the equivalence ratio and the kind of inert gas. It is also shown the region of convex part of flame toward the unburned gas is greater than that of toward the burned gas regardless of the kind of inert gas.

Study on the Enhancement of Design Technology for the Evaporation Pot Type Kerosene Burner (기화식 석유버너의 설계기술 향상 연구)

  • Shim, S.H.;Kim, S.J.;Keel, S.I.;Hong, Y.J.;Yun, J.H.;Kim, I.K.;Kim, Y.S.
    • 한국연소학회:학술대회논문집
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    • 1998.10a
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    • pp.47-57
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    • 1998
  • Characteristics of evaporation, flame propagation at moment of ignition and steady state combustion, and flow characteristics of combustible mixture have been investigated by experiments and computational simulation for the evaporation pot type kerosene burner. The results show how to design the evaporation pot in order to minimize the sticking of residual tar, and also indicate that symmetrical flame propagation along the flame ring from the kernel of ignition is achieved by modication of the shape of ignition part. In the case of steady state combustion, the uniform distribustion of flame at each flame hole is accomplished by proper modification of the piping instruments. The improved design of the structure and parts of the kerosene burner make up enhancement of flame stability and considerable reduction of CO and bad smell emission at moment of ignition.

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