• 제목/요약/키워드: Air combustion

검색결과 2,236건 처리시간 0.032초

연소용 공기 공급 불균일을 고려한 발전 보일러내 연소환경 시뮬레이션 (Computational Simulation of Combustion in Power Plant Boiler According to Un-Even Combustion Air)

  • 고영건;최상민;김영주
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2005년도 제31회 KOSCO SYMPOSIUM 논문집
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    • pp.85-92
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    • 2005
  • Oil-fired power plants usually use several burners and the combustion air is supplied to each burner through the complicated duct which is called windbox. A windbox should be designed to supply combustion air to each burner evenly but, due to the complicated duct shape, flow distribution in the windbox is unbalanced and uneven supplies of combustion air to each burner are induced by these unbalanced flow distribution in the windbox. These flow patterns tend to make flame unstable, increase the formation of pollutants and lower the overall combustion efficiency. To prevent these disadvantages, flow patterns in the windbox should be investigated for the uniform flow distribution. In this study, computational simulation method was used to investigate the flow distribution in the windbox and measured the velocities at the exit of burners in the real windbox to compare with CFD results. The results show two significant flow patterns. One is that the flow rates of each burner are different from each other and this means that all burners operate in different conditions of air to fuel ratio. The other is that the flow distribution at the exit of each burner is not axi-symmetric although the burner shape is axi-symmetric and this increases the pollutant products like CO.

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2차 공기 주입방식에 따른 스토커형 소각로의 연소특성에 관한 수치해석적 연구 (A Numerical Study on the Combustion Characteristics for Stoker Type Incinerator with Various Injection Type of Secondary Air)

  • 정진;김창녕;조영민
    • 설비공학논문집
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    • 제15권10호
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    • pp.835-842
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    • 2003
  • A three dimensional numerical analysis has been conducted for a stoker type incinerator which has the capacity of 1.5 ton/hr. The objective of the present study is to predict the effects of swirl induced by secondary air and to find an optimal operating condition of the incinerator. In this study, combustion characteristics such as distributions of temperature, velocity and concentration of each species have been examined with various injection types of secondary air and with different flow rates of secondary air in the incinerator. It is found that the secondary air injection on the combustion process makes the path of fluid particle longer in the combustor and enhances the mixing between air and combustion gas by arousing a swirl. Therefore, the injection type of secondary air can be an important key in the design process of incinerator.

MPI 엔진용 공기 보조 인젝터의 분무 미립화 및 연소 특성에 관한 연구 (A Study on the Atomization and Combustion Characteristics of Air-assisted Injector in MPI Engine)

  • 서영호;이창석
    • 한국자동차공학회논문집
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    • 제6권1호
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    • pp.52-58
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    • 1998
  • The spray characteristics of air-assisted fuel injection and its effects on the engine combustion was investigated in this study. The atomization characteristics of a Bosch fuel injector inserted into the air-assist adapter were measured using particle motion analysis system. Droplet size decreased with air supplied and fine spray with below $60\mu\textrm{m}$ of SMD was acquired under the conditions of air-assist pressure over 0.5bar. The lean combustion performance of a 1.8L DOHC engine equipped with air-assist adapters was tested on the dynamometer. When the assistant air pressure is 1.0bar, lean limit recorded the highest value, and CO, HC emissions were decreased at the pressure over 1.0bar.

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디젤엔진 연소공기 습식여과기의 개발에 관한 연구 (A Study on Development of the Wet Type Filter for Combustion Air of Diesel Engine)

  • 김용석;박성호;양순용
    • 한국공작기계학회논문집
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    • 제17권1호
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    • pp.158-164
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    • 2008
  • In this paper, the performance of wet type filter for diesel engine combustion air has been studied with effects of air temperature, humidity, and pressure. After experiments are performed without diesel engine, it has been investigated the applicability to diesel engine. Wet type filter for diesel engine combustion air had advantages that it is not necessary to change air filter and that engine exhaust gas is environmentally friendly due to low NOx and particulate emission. Also, the filtration performance has been carried out with smoke shell.

1MWth 실험연소로를 이용한 석탄의 연소특성 연구 (Study on Coal Combustion Characteristics with 1MWth Test Facility)

  • 장길홍;장인갑;정석용
    • 대한기계학회논문집B
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    • 제23권11호
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    • pp.1464-1472
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    • 1999
  • Design and operation of $1MW_{th}$ pulverized coal combustion testing facility are described. Also the influence of air staging on NOx emission and burnout of coal flames was investigated in this facility. The test facility consisted of coal feeding system, firing system and flue gas treatment system. A top-fired externally air staging burner was adopted in order to avoid influence of gravity on the coal particles and for easy maintenance. Distribution of temperature and chemical species concentration of coal flames could be measured in vertical pass of furnace. Main fuel was pulverized (83.4% less than $80{\mu}m$) Australian high bituminous coal. From variety of test conditions, overall excess air ratio was selected at 1.2(20% excess air). Tho study showed that increasing the staged air resulted in lower NOx omission, and it was suggested to be more than 40% of the total combustion air for the substantial NOx reduction. Sufficient burnout was not achievable when NOx emission was less than 500ppm. Also, the amount of core air did not influence tho NOx reduction.

하이브리드/이중 선회제트 연소기에서 공기 예열온도에 의한 배출 특성 연구 (A study of Overall Combustion Characteristics according to the Air Preheated Temperature in a Hybrid/Dual Swirl Jet Combustor)

  • 최인찬;조준익;이기만
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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    • pp.149-152
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    • 2012
  • The laboratory experiments have been conducted to investigate the effects of air preheated temperature on the emission characteristics by a model gas turbine burner with a hybrid/dual swirl jet flames configuration. The concentration of NOx and CO emissions, and flue gas temperature at combustor exit were measured with varying the equivalence ratio for different air preheated temperatures of 300, 400, 500K at atmospheric pressure. It was overall shown that the NOx and CO emissions, and flue gas temperature were decreased according to the decreasing of equivalence ratio due to the effects of lean premixed combustion regardless of the air preheated temperature. Experimental results of a lean premixed flames configuration indicated that the NOx emission was increased with higher inlet air temperature and air flow rate, which is attributed to the increasing of flue gas temperature and heat release related to the thermal NOx mechanism. But the CO emission was shown the opposite tendency, that is, the CO emission was decreased with increasing of inlet air temperature and flow rate.

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Effect of Air Velocity on Combustion Characteristics Scale Burner

  • Laryea, Gabriel Nii;No, Soo-Young
    • 한국농업기계학회:학술대회논문집
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    • 한국농업기계학회 2005년도 동계 학술대회 논문집
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    • pp.76-82
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    • 2005
  • This paper presents the combustion characteristics of hydrocarbon fuel from a conventional pressureswirl nozzle of a small-scale burner. The nozzle has orifice diameters of 0.256 mm and liquid flow rates raging from 50 to 64 mL/min were selected for the experiments. The furnace temperature distribution along the axial distance, the gas emission such as CO, $CO_2,\;NOx,\;S0_2,$ flue gas temperature, and combustion efficiency were studied. The local furnace and flue gas temperatures decreased with an increase in air velocity. At injection pressures of 1.1 and 1.3 MPa the maximum furnace temperatures occurred closer to the burner exit, at an axial distance of 242 mm from the diffuser tip. The CO and $CO_2$ concentrations decreased with an increase in air velocity, but they increased with an increase in injection pressure. The effect of air velocity on NOx was not clearly seen at low injection pressures, but at injection pressure of 1.3 MPa it decreased with an increase in air velocity. The effect of air velocity $SO_2$ concentration level is not well understood. The combustion efficiency decreased with an increase in air velocity but it increased with an increase in injection pressure. It is recommended that injection pressure less than 0.9 MPa with air velocity not above 8.0 m/s would be suitable for this burner.

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기체분리막에 의해 상승된 산소농도가 스파크점화기관의 연소에 미치는 영향 (The effects of oxygen-concentration increased by oxygen-enriching membrane on combustion of S.I. engines)

  • 권병철;김형섭
    • 오토저널
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    • 제14권6호
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    • pp.74-80
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    • 1992
  • The purpose of this study is to improve the performance of gasoline engine. Combustion-characteristics orignated from supplying cylinder with fuel-air mixture which was formed by the rise of oxygen-concentration in air with oxygen-enriching membrane have been investigated. The results showed that the poor-limit of oxygen-concentration was increased by shortening combustion-duration because the rise of oxygen-concentration in fuel-air mixture resulted in the promotion of combustion-velocity. Also, the generation of large output of power was expected from combustion in proportion as the amount of oxygen was increased.

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연료-공기 비혼합도가 희박예혼합 연소 특성에 미치는 영향 (Effects of Fuel-Air Unmixedness on Lean Premixed Combustion Characteristics)

  • 김대현;이종호;전충환;장영준
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2002년도 제24회 KOSCO SYMPOSIUM 논문집
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    • pp.133-139
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    • 2002
  • The lean premixed technique has been proven very efficient in reducing NOx emissions from gas turbine combustors. However combustion instability is susceptible to occur in lean premixed combustor. So laboratory-scale dump combustor was used to understanding the underlying mechanisms causing combustion instabilities. In this study, tests were conducted at atmospheric pressure and inlet air was up to $360^{\circ}C$ with natural gas. The observed instability was a longitudinal mode with a frequency of ${\sim}341.8Hz$. At selected unstable conditions, phase-resolved OH chemiluminescence images were captured to investigate flame structure with various equivalence ratio. Combustion instability was observed to occur at higher value of equivalence ratio(>0.69). This study was performed to investigate the effects of equivalence ratio and fuel split measuring NOx and acoustic wave. The results reveal the effect of fuel-air unmixedness on lean premixed combustor.

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가스보일러 연소실 공기분배판의 기하학적 형상에 따른 유동특성 해석 (Flow Characteristic Analysis in Accordance with Geometrical Modification of Air Distribution Plate in Gasboiler Combustion Chamber)

  • 김재중;손영갑;장석원;유동수
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 춘계학술대회논문집B
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    • pp.859-864
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    • 2000
  • This paper reports a numerical flow characteristic analysis in gas boiler combustion chamber. The numerical results with simplification and assumptions were found within 30% of the experiment. A lot of geometrical modification has been invested in attempt to obtain the uniform flow in the combustion chamber exit. As a result, the velocity magnitude of the combustion chamber is relate with the hole size in air distribution plate. The velocity uniformity of the combustion chamber is relate with the number of holes and location in air distribution plate.

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