• Title/Summary/Keyword: Excess air ratio

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Experimental study on combustion characteristics of oxy-fuel glass melting furnace (순산소를 이용한 유리 용해로의 연소특성에 관한 실험적 연구)

  • Kim, Se-Won;Ahn, Jae-Hyun;Kim, Yong-Mo;Shin, Myung-Chul
    • Journal of the Korean Society of Combustion
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    • v.9 no.1
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    • pp.1-10
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    • 2004
  • The results of a series of experiments executed by using two pilot-scale oxy-fuel burners are presented. The oxy-fuel burners are designed for maximum capacity of 50,000kcal/hr, 200,000kcal/hr and installed in the test furnace. The effects of turn-down ratio, excess oxygen ratio, nozzle exit velocity, injection angle, and swirl vane angle on the combustion characteristic are investigated. Temperature distributions are measured using R-type and Molybdenum sheathed C-type thermocouple at various points of the flame. The results showed that maximum temperature and mean temperature increase with the increase of turn-down ratio and momentum. The maximum flame temperature was increased about 35% compared to the case of equivalent air operated condition. In addition, optimum burner type, excess oxygen ratio and nozzle characteristics are obtained for this oxy-fuel glass melting furnace.

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A Study on the Reduction of $NO_x$ Emission from Dual Fuel Engine for Co-generation System (열병합발적용 Dual Fuel Engine의 질소산화물 배출저감에 관한 연구)

  • 정일래;김용술;심용식
    • Journal of Korean Society for Atmospheric Environment
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    • v.7 no.1
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    • pp.31-40
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    • 1991
  • This study shows the correlation between $NO_x$ emission in the exhaust gas and various operation factors of dual fuel engine for Co-generation system. General tendency was shown that the thermal efficiency was lowered by the change of operation factors. However these were not confirmed on this experiment. Increasing T4 temperature (exhaust gas temperature at turbo-charger inlet) reduces $NO_x$ emission rate. The higher T4 temperature requires lower excess air as the excess air ratio is controlled by T4 temperature on gas mode operation. Another tendency was that $NO_x$ emission rate is reduced in case of increasing boost air temperature, quantity of pilot oil or bypassing flue gas through the exhaust gas boiler. The diameter of the fuel injection nozzle was changed smaller than design value and the injection timing was readjusted. Thus $NO_x$ emission rate could be reduced as retarding injection timing and changing hole diameter of fuel injection nozzle, however maxium engine out-put was decreased by changing fuel nozzle on the diesel mode operation.

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An Experimental Study on the Combustion Characteristics with Superadiabatic Combustor in Porous Media (다공성물질을 이용한 초단열 연소장치에서의 연소특성의 실험적 연구)

  • Chae, J.O.;Dobrego, K.V.;Sim, M.S.;Chung, S.C.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.6 no.4
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    • pp.399-405
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    • 1994
  • Beacuse of the energy resources exhaustion, the aggravating environmental air pollution and the smoke phenomena etc., the importance of clean gas fuel compared with liquid fuel is highly considered in recent years. The combustion system which consists of porous media is actively studied as a new method for solving above problems. Therefore, excess enthalpy combustion using porous media was interested by many researchers and investigated through numerical and experimental analysis. In this study, the simplified combustor has the unique combustion characteristics of mixture gas preheated effect using radiative and convective heat energy by changing the flow passage of unburned gas with solenoid valves and has the intensive excess enthalpy phenomena As the result of according to reduce equivalence ratio, flame temperature was remarkably higher than adiabatic flame temperature. This show the ability of super-lean combustion.

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Improvement of Thermal Efficiency and Emission by Lean Combustion in a Boosted Spark-Ignition Engine Fueled with Syngas (합성가스 스파크점화 과급 엔진에서 희박 연소를 통한 열효율 및 배기 개선)

  • Park, Hyunwook;Lee, Junsun;Jamsran, Narankhuu;Oh, Seungmook;Kim, Changup;Lee, Yonggyu;Kang, Kernyong
    • Journal of ILASS-Korea
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    • v.26 no.1
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    • pp.40-48
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    • 2021
  • Lean combustion was applied to improve the thermal efficiency and emission in a single-cylinder, spark-ignition engine fueled with syngas. Under naturally aspirated conditions, the lean combustion significantly improved the thermal efficiency compared to the stoichiometric combustion, mainly due to the reduction in heat transfer loss. Intake air boost was applied to compensate the low power output of the lean combustion. The gross indicated power of 24.8 kW was achieved by increasing the intake pressure up to 1.6 bar at excess air ratio of 2.2. The nitrogen oxides showed near zero level, but the carbon monoxide emission was significant.

A Study of the Combustion Characteristics Using a 2-valve Sl Optically Acessible Engine with SCV (SCV를 장착한 2밸브 Sl 가시화기관의 연소특성에 관한 연구)

  • Jeong, Gu-Seop;Jeon, Chung-Hwan;Jang, Yeong-Jun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.12
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    • pp.1692-1701
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    • 2001
  • This study describes the combustion characteristics under various condition of air excess ratio and ignition timing in a 2-valve SI optically accessible engine with swirl control valve(SCV). It adapted three different types of SCV(open ratio 72.5%, 78%, 59%) to strengthen a swirl flow. Pressure data were acquired using pressure sensor to investigate the effect of swirl flow on combustion, and from these pressure data, IMEP(indicated mean effective pressure) and MFB(mass fraction burnt) were calculated to explain burn rate and flame speed. From acquired flame images, we inspected the flame propagation direction, flame area, and flame centroid. Flame propagation direction showed different tendency between with/without SCV, and flame area with SCV was faster and larger than that of conventional engine. Finally, the representative flame images at each crank angle were acquired by PDF method to verify flame growth process. It is found that strengthened swirl flow is more beneficial for faster and stable combustion.

Desulfurization Characteristics of Domestic Anthracite by Limes at Bench Scale Pressurized Fluidized Bed Combustor . (벤치규모 가압유동층연소로에서 석회석에 의한 국내무연탄의 탈황특성)

  • Han, Geun-Hui;Ryu, Jeong-In;Jin, Gyeong-Tae
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.10
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    • pp.1373-1383
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    • 2001
  • The desulfurization characteristics of anthracite in a bench scale pressurized fluidized bed combustor are investigated. The coal used in the experiment is domestic anthracite from Kangwon Taeback area. The desulphurization experiment is performed with limestone from Chungbuk Danyang. The pressure of the combustor is maintained at 6 atm, and the combustion temperatures are 850, 900, and 950$\^{C}$. The superficial gas velocities are 0.9, 1.1, and 1.3 m/s. The excess air ratio is varied from 5 to 35%. The Ca/S mole ratios are 0.5, 1.5, 2.5 and 4.5 mole. All experiments are executed at 2m bed height. Consequently, SO$_2$ concentration in the flue gas is increased with incresing bed temperature and superficial gas velocity. However SO$_2$ concentration is decreased with incresing excess air ratio and Ca/S mole ratio.

Investigation of Heating Performance of Kerosene Fan Heater (석유 홴 히터의 난방 능력 고찰)

  • Kim, Jang-Kweon;Jeong, Kyu-Jo
    • Journal of Power System Engineering
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    • v.1 no.1
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    • pp.51-60
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    • 1997
  • In this paper, we investigated the heating performance and the basic characteristics required for normal combustion of kerosene fan heater. And also the iso-velocity contours and the iso-temperature contours of hot gas discharged from the exit of kerosene fan heater were analyzed. The experiment was carried out with kerosene fan heater attached to the blow-down-type subsonic wind tunnel with a test section of $240mm{\times}240mm{\times}1200mm$. The purpose of this paper was to obtain the basic data for new design from conventional kerosene fan heater. Consequently it was found that (i) the pressure ratio $P_2/P_1$ had a comparatively constant value of 0.844 according to the increase of the revolution of turbo fan, (ii) the primary excess air ratio had a range of $0.84{\sim}1.11$ during normal combustion, and (iii) the heating performance of kerosene fan heater had a range of $1,494{\sim}3,852kcal/hr$.

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Effect of Compression Ratio Change on Emission Characteristics of HCNG Engine (압축비 변화가 수소-천연가스 엔진의 배기특성에 미치는 영향)

  • Lee, Sung Won;Lim, Gi Hun;Park, Cheol Woong;Choi, Young;Kim, Chang Gi
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.37 no.5
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    • pp.473-479
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    • 2013
  • This study focused on a heavy-duty natural gas engine fuelled with HCNG (CNG: 70 vol%, hydrogen: 30 vol%) and CNG. To study the emission characteristics of an HCNG engine with high compression ratio, the exhaust gas of CNG and HCNG fuel were analyzed in relation to the change in the compression ratio at the half load condition. The results showed that the thermal efficiency improved with an increase in the compression ratio. Consequently, $CO_2$ emission decreased. CO emission increased with inefficient oxidation due to the low exhaust gas temperature. $NO_x$ emission with high compression ratio was increased at the same excess air ratio condition. However, $NO_x$ emission was not affected by a compression ratio exceeding ${\lambda}$ = 1.9 because of the same MBT timing.

A Study on Tuning Effects of Intake Manifold, Intake Pipe and Air Filter upon Performance and Exhaust Emissions of Driving Car (운행자동차 성능 및 배기 배출물에 미치는 흡기 다기관, 흡기 파이프 및 공기필터의 튜닝효과에 관한 연구)

  • Bae, Myung-whan;Ku, Young Jin;Park, Hui-seong
    • Transactions of the Korean Society of Automotive Engineers
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    • v.24 no.5
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    • pp.538-548
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    • 2016
  • The purpose of this study is to identify the possibility of effective tuning works, understand the characteristics of tuning engine, and analyse the basic data of engine tuning inspection corresponding to the safe operation and environment of a driving gasoline car. The effects of tuning on the characteristics of performance and exhaust emissions under a wide range of engine speeds are experimentally investigated by the actual driving car with a four-cycle, four-cylinder DOHC, turbo-intercooler, water-cooled gasoline engine operating at four types of non-tuning, tuning 1, 2 and 3. The tuning parts in the gasoline engine are the intake manifold, intake pipe and air filter. In the experiment, the output, torque and air-fuel ratio of the five-speed automatic transmission vehicles were measured at the chassis dynamometer(Dynojet 224xLC) with one person on board. The exhaust emissions of $NO_X$, THC, CO, $O_2$ and $CO_2$, and excess air ratio(${\lambda}$) at the other chassis dynamometer(DASAN-MD-ASM-97-KR-HD) were also measured by the idle/constant-speed mode(ASM2525 mode) test method. It is found that the actual air-fuel ratios of non-tuning and tuning engines were shown to be lower than the stoichiometric air-fuel ratio with increasing engine speed, and the actual air-fuel ratio of non-tuning engine was slightly higher than those of tuning engines when the engine speed is more than 4000 rpm. The output was significantly increased by the tuning whereby the maximum output of tuning engine was more increased to approximately 117.64% than that of non-tuning engine. In addition, CO, THC and $NO_X$ emissions of non-tuning and tuning engines measured by the constant-speed test mode were all satisfied with the inspection standards. CO emission was increased, while THC and $NO_X$ emissions were reduced by tuning.

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

  • 권병철;김형섭
    • Journal of the korean Society of Automotive Engineers
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    • v.14 no.6
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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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