• Research Article

    The Effect of Target Species Changing on the Mechanism Reduction in DRGEP Method

    DRGEP 방법에서의 표적 화학종 변화가 메커니즘 축소에 미치는 영향

    Jun Woo Jung, Young Chan Lim and Hyun Kyu Suh

    정준우, 임영찬, 서현규

    This study investigated the effect of target species changing on the mechanism reduction in DRGEP(Directed Relation Graph Error Propagation) method. To ... + READ MORE
    This study investigated the effect of target species changing on the mechanism reduction in DRGEP(Directed Relation Graph Error Propagation) method. To achieve this goal, the automatic mechanism reduction scheme of reaction workbench which includes DRGEP method was introduced and the 0-D combustion analysis of CHEMKIN-PRO was executed to confirm the error rate of ignition delay between the detailed mechanism and reduced mechanisms. To consider various target species, the skeletal mechanism for biodiesel and n-heptane mechanism were merged and the various environments were considered to decide the environment of the mechanism reduction by changing the relative and absolute tolerance associated with the mechanism reduction. As a result, it was confirmed that the target species has a great influence on the reduction of the mechanism, and it was appropriate to consider chemical species, as the target species, associated with exhaust emissions. - COLLAPSE
    September 2019
  • Research Article

    An Experimental Study of Propene Reaction of a Laminar Flow Reactor and Validation of its Reduced Mechanism

    층류 유동반응기를 이용한 프로핀 반응 실험 및 축소 메커니즘의 검증

    Cheon Hyeon Cho, Ka Ram Han, Chae Hoon Sohn and Jeongsik Han

    조천현, 한가람, 손채훈, 한정식

    Flow reactors are classified into laminar flow, turbulent flow and jet-stirred reactors depending on flow condition. Laminar flow reactor is a device ... + READ MORE
    Flow reactors are classified into laminar flow, turbulent flow and jet-stirred reactors depending on flow condition. Laminar flow reactor is a device that measures oxidation process of gaseous fuel and vaporized liquid fuels. Propene oxidation process was observed in a laminar flow reactor with a specified residence time at 6 atm, 968 K, and equivalence ratio of 0.71 and compared with numerical simulations. The Aramco 2.0 chemistry was adopted as a kinetic mechanism which includes 493 species and about 2,700 reaction steps. Oxygen, carbon monoxide, and carbon dioxide concentrations were measured. Numerical results with a time shift of 0.216 s show a good agreement with experimental results. And, a reduced kinetic mechanism was generated and validated based on the Aramco 2.0. The reaction steps are reduced by 23%. - COLLAPSE
    September 2019
  • Research Article

    Numerical Study on Combustion Characteristics of Hydrogen Gas Turbine Combustor using Cross flow Micro-mix System

    Cross flow Micro-mix 방식을 이용한 수소 가스터빈 연소기연소특성에 대한 수치해석적 연구

    Chun Loon Cha and Sang Soon Hwang

    차천륜, 황상순

    In response to the tight regulation of CO2 emissions, studies on gas turbines for aviation based on hydrogen fuel have recently become ... + READ MORE
    In response to the tight regulation of CO2 emissions, studies on gas turbines for aviation based on hydrogen fuel have recently become more important. Especially the Micro-mix combustion method is one of the promising combustion technologies that inherent safety against flash-back and low NOx emission due to a very short residence time of reactants in the flame region. In order to analyze the stability and low NOx emission characteristics of a gas turbine combustion system using hydrogen fuel and micro-mix technology, a series of numerical approach were performed in this study. The results show that, as the supplied fuel flow rate and the diameter of the fuel supply nozzle were increased, a stable hydrogen micro-mix combustion flame was formed. - COLLAPSE
    September 2019
  • Research Article

    Pressure Effect on NO Formation in H2/CO Premixed Flames

    H2/CO 예혼합화염에서 NO 배출에 대한 압력 영향

    Sungwoo Park

    박성우

    The purpose of the present study is to better understand the pressure effect on NO formation in H2/CO/air premixed flames ... + READ MORE
    The purpose of the present study is to better understand the pressure effect on NO formation in H2/CO/air premixed flames. A recently developed detailed chemical kinetic model by merging AramcoMech 3.0 and a comprehensive nitrogen chemistry is first compared against experimental data of H2/CO mixtures including NO formation in premixed flames. Freely propagating H2/CO/air premixed flames are then simulated over a pressure range 1-20 atm and temperatures of 1886 and 1986K. NO formation via N2O becomes important between reaction zone and postflame region with increasing pressure, but NO concentrations in the reaction zone is not sensitive to increasing pressure. Thermal NO production pathways lead to the total NO formation in the postflame zone and the total NO formation rate increases with increasing pressure. - COLLAPSE
    September 2019
  • Research Article

    Experimental Study on Slow Pyrolysis of Biomass by Direct and Indirect Contact Heat Transfer in a Continuous Reactor

    직접 및 간접열교환에 따른 연속식 반응기 내 바이오매스 저속열분해 특성에 대한 실험적 연구

    Jungkeuk Park, Sangho Kim, Jinje Park, Seunghan Yu and Changkook Ryu

    박정극, 김상호, 박진제, 유승한, 류창국

    Biochar from pyrolysis is emerging as a new option for biomass utilization for various purposes including soil amelioration and carbon sequestration. This ... + READ MORE
    Biochar from pyrolysis is emerging as a new option for biomass utilization for various purposes including soil amelioration and carbon sequestration. This study investigated the slow pyrolysis characteristics of wood pellet in a continuous reactor varying the heat transfer type (direct and indirect contact) at various temperatures (400~700℃) with different carrier gas compositions (inert, O2 2%, and O2 4%). Direct contact heat transfer by preheated carrier gas accelerated the heat up of biomass, promoting the pyrolysis process as well as the temperature increase of indirect contact cases. The presence of O2 in the carrier gas resulted in limited oxidation reactions with pyrolytic vapor, increasing the reactor temperature to 529.4℃ and 591.7℃ at 2% and 4% O2, respectively, compared to the inert case having a final temperature of 492.4℃. This can be exploited to save the external heat supply but a careful temperature control is required to yield uniform biochar properties. The pyrolysis products from different test conditions were characterized for mass yield and detailed properties of biochar, bio-oil, and non-condensable gases. - COLLAPSE
    September 2019
  • Research Article

    Laminar Burning Velocity Measurement of Spherical Propagating SNG-air Premixed Flames through Verification of Combustor

    연소기 검증을 통한 구형으로 전파하는 SNG-공기 예혼합 화염의 층류연소속도 측정

    Junho Song, Seohee Cho and Keeman Lee

    송준호, 조서희, 이기만

    An experimental study was conducted to determine laminar burning velocity and Markstein length of SNG fuel from spherical propagating flames at normal ... + READ MORE
    An experimental study was conducted to determine laminar burning velocity and Markstein length of SNG fuel from spherical propagating flames at normal and elevated pressure conditions. In order to make accurate results, combustion chamber was verified using methane/air mixture to find suitable extraction method and flame radius range in SNG fuel. In addition, ARAMCO 2.0 mechanism was selected to compare experimental results with numerical values. As results of this study, there were found that the laminar burning velocities and Markstein lengths of SNG fuel decreased as initial pressure rose. Pressure exponent tended to increase and decrease as the equivalence ratio increased. - COLLAPSE
    September 2019