• Research Article

    Experimental Study of Flameless Combustion of Methane in Oxygen-Enriched Condition

    산소 부화 조건의 메탄 무화염 연소에 관한 실험적 연구

    Donghee Kim, Kang Y. Huh and Youngjae Lee

    김동희, 허강열, 이영재

    This study was conducted to analyze the characteristics of flameless combustion and emissions using the lab-scale flameless combustion system fueled with methane ... + READ MORE
    This study was conducted to analyze the characteristics of flameless combustion and emissions using the lab-scale flameless combustion system fueled with methane. Especially, experiments were performed under oxygen-enriched conditions to expand the applications of flameless combustion and NOx reduction. The combustor able to induce the internal flue gas recirculation was applied, while the preheating of fuel and oxidant was not considered. The fraction of oxygen in oxidant was varied from 24.4% to 26.3%. The heat input was fixed at 3 kWth in all cases. From the experimental results, there was three combustion modes as the conventional flame, transitional period and flameless combustion. In the transitional period, the ignition and extinction of flame occurred repeatedly. Also, the flue gas compositions and pressure of the combustor were unstable. In the flameless combustion, the hot-spot of the conventional flame disappeared and the temperature distribution of the combustor became uniform. Moreover, the thermal-NOx was reduced in the flameless combustion mode and the trade-off relationship between CO and NOx was improved. - COLLAPSE
    September 2020
  • Research Article

    Validation of CFD Analysis and Flow Characteristics of GP3 Rotary Engine at Motoring Condition

    모터링 GP3 로타리 엔진의 CFD 해석법 검증 및 유동 특성 분석

    Chang-Eon Lee, Hohyun Yu, Do-hyun Kim and Taejoon Park

    이창언, 유호현, 김도현, 박태준

    This study presents 3D CFD analysis for the first version experimental rotary engine originated from 3 lobes Gerotor pump (GP3 RTE). The ... + READ MORE
    This study presents 3D CFD analysis for the first version experimental rotary engine originated from 3 lobes Gerotor pump (GP3 RTE). The CONVERGE software is used for its powerful tool for automatic meshing and combustion modeling with detailed chemistry mechanism. The CFD methods are validated and flow characteristics with four strokes are clarified. The results describe the unique characteristic of the new engine well and may allow powerful tool to validate design parameters. Specifically, the EGR behavior during the intake-exhaust port overlap and the interference phenomenon during the port overlap between neighboring cylinders, unique to the engine, must be investigated thoroughly to get good performance of the engine. - COLLAPSE
    September 2020
  • Research Article

    Validation of CFD Analysis and Combustion Characteristics of GP3 Rotary Engine at Firing Condition

    GP3 RTE의 연소장 해석법의 검증 및 연소 특성 분석

    Chang-Eon Lee, Do-hyun Kim, Hohyun Yu and A-Sun Yoon

    이창언, 김도현, 유호현, 윤아선

    This study presents 3D CFD analysis for the first version experimental rotary engine originated from three lobes Gerotor pump (GP3 RTE). The ... + READ MORE
    This study presents 3D CFD analysis for the first version experimental rotary engine originated from three lobes Gerotor pump (GP3 RTE). The CONVERGE software is used due to its powerful tool for combustion modeling with detailed chemistry mechanism. The reduced reaction models based on GRI-Mech 3.0 full reaction mechanism are validated and reasonable ranges of target species and error tolerance are selected. The results describe well the unique characteristic of the new engine. Specifically, the information on EGR behavior during the port overlap, quenching regions, indicated power and efficiency, and emission characteristics may allow powerful tool to validate the design parameters. - COLLAPSE
    September 2020
  • Research Article

    Combined Use of Tunable Diode Laser Absorption Spectroscopy and Laser-Induced Breakdown Spectroscopy for Temperature Field Reconstruction

    가변파장 레이저흡수분광법과 레이저유도플라즈마 분광법 복합을 통한 온도장 재건

    Jungwun Lee, Cheolwoo Bong, Jihyung Yoo and Moon Soo Bak

    이준권, 봉철우, 유지형, 박문수

    A new technique that reconstructs the temperature and species-concentration fields by using tunable diode laser absorption spectroscopy (TDLAS) and laser-induced breakdown spectroscopy ... + READ MORE
    A new technique that reconstructs the temperature and species-concentration fields by using tunable diode laser absorption spectroscopy (TDLAS) and laser-induced breakdown spectroscopy (LIBS) is demonstrated on axisymmetric combustion fields. For two-line thermometry, the uncertainties in linestrengths of the absorption lines cause systematic errors in both temperature and species concentration estimations. Thus, in the study, the radial profile of water vapor concentration is obtained first using LIBS, assuming that the combustion is complete; then, the radial temperature profile is estimated from the radial profile of the absorption coefficient, as reconstructed from the absorbance profile obtained using TDLAS. The spectral line of water vapor at 7185.6 cm-1 is selected because its linestrength showed a monotonic decrease with the increase in temperature within the measuring temperature range. The radial profiles of temperature and water mole fraction are well-reconstructed, and the measurement error is found to be as low as 3%. - COLLAPSE
    September 2020
  • Research Article

    Numerical Study on the Constant Volume Combustion Characteristics of Biodiesel According to the Change of EGR Rate

    EGR rate 변화에 따른 바이오디젤 정적 연소 특성에 관한 수치해석 연구

    In Gang Park, Young Chan Lim and Hyun Kyu Suh

    박인강, 임영찬, 서현규

    This paper was conducted to investigate the effect of EGR on the combustion characteristics, NOX and CO formation characteristics of constant ... + READ MORE
    This paper was conducted to investigate the effect of EGR on the combustion characteristics, NOX and CO formation characteristics of constant volume combustion of the biodiesel fuel. To achieve this, methyl decanoate, methyl 9 decenoate, and n-heptane species were applied for the simulation of the biodiesel and diesel chemical reactions during the constant volume combustion process. The analysis of biodiesel-EGR combustion was performed by simultaneously considering the mole fraction which was composed of the N2, H2O, CO2, and O2 species according to the EGR rate (10~60%). As a result of the combustion characteristics, the maximum OH radical was reduced as the EGR rate increase, and the ignition delay was increased at the same time. Most of NOX emission was generated by the thermal NOX reaction, and it was not emitted after the EGR rate of 30% conditions due to the decrease of combustion temperature and oxygen concentration. The reactivity of CO generation was showed the high absolute rate of production in the reaction path related to the reactions of HCO radical, and it has a trade-off relationship with the tendency of NOX emissions. In addition, it was indicated that the UHC emission increased rapidly since the chemical reactions related to the fuel oxidation did not occur actively when the ambient temperature was 800~1,000 K and the EGR rate was 60% conditions. - COLLAPSE
    September 2020
  • Research Article

    NOx Reduction by Co-Firing and Reburning of Biomass in 1MWth Coal Combustion

    1MWth 석탄 연소로에서 바이오매스 혼소 및 재연소를 통한 NOx 저감 연구

    Taeyoung Chae

    채태영

    This study was investigated co-firing of biomass and coal for NOx reduction using 1 MWth multi-burner furnace. NOx acts as a ... + READ MORE
    This study was investigated co-firing of biomass and coal for NOx reduction using 1 MWth multi-burner furnace. NOx acts as a precursor of particulate matter formation and the minimization of its release from coal combustion has becomes an urgent issue. Three biomass types (wood pellet, torrefied biomass, and empty fruit bunch) were tested at different ratios through direct co-firing with coal and separate feeding as reburn fuel. It was found that the NOx reduction was achieved by up to 25% by direct co-firing and up to 50% by reburning. Although co-firing biomass as reburn fuel was more efficient for NOx reduction, further investigation is required for its applications in commercial plants. - COLLAPSE
    September 2020