• Research Article

    Process Simulation of the Effect of Ammonia Co-firing on the Supercritical Boiler System for Reduction of Greenhouse Gas

    온실가스 저감을 위한 암모니아 혼소가 초임계 화력 발전시스템 보일러에 미치는 열성능 영향성 평가

    Seong-il Kim, Hyung geun Kwak and Won Yang

    김성일, 곽형근, 양원

    Co-firing ammonia with coal is emerging as a transitional technology in the power industry for the major reduction of greenhouse gas emissions. … + READ MORE
    Co-firing ammonia with coal is emerging as a transitional technology in the power industry for the major reduction of greenhouse gas emissions. Although ammonia has the disadvantages of low combustion reactivity and the generation of nitrogen oxides, it can effectively reduce greenhouse gas due to the generation of only moisture and nitrogen after the combustion. Therefore, for the efficient co-firing of the coal and ammonia in the power plant system, it is essential to evaluate the effect of co-firing ammonia on the boiler system. We selected the 870 MWe supercritical coal-fired boiler system and developed the process simulation model of the target boiler system. In this study, process simulation of the target boiler system was performed according to the ammonia co-firing ratio of 0, 5, 10, 20, and 30%. In addition, the effect of ammonia co-firing on the boiler thermal performance was evaluated according to the load condition and the quality of coal. As the ammonia co-firing ratio increases, the flue gas flow rate and the radiation and convective heat transfer rate decrease. Accordingly, the main and reheat steam temperatures decrease. Although the reduction of carbon dioxide is quantitatively confirmed according to the co-firing ammonia, the boiler thermal efficiency decreases due to the increase in the amount of moisture in the flue gas. - COLLAPSE
    31 December 2021
  • Research Article

    A Numerical Study on the Thermal Decomposition of n-dodecane at Various Mass Flow Rate for Super-critical Condition in a Cylindrical Tube

    초임계 조건에서 질량 유량 변화에 따른 원통관내 n-dodecane의 열분해 반응에 관한 수치적 연구

    Seunghyeok Lee, Yuangang Wang and Chae Hoon Sohn

    이승혁, 왕위엔강, 손채훈

    Numerical simulation on thermal decomposition reaction of n-dodecane in a cylindrical tube is conducted by changing mass flow rate. Thermal decomposition mechanism … + READ MORE
    Numerical simulation on thermal decomposition reaction of n-dodecane in a cylindrical tube is conducted by changing mass flow rate. Thermal decomposition mechanism adopted in the present study is the proportional product distribution (PPD) model for n-dodecane, which is a 1-step global mechanism. All of simulations are performed atr the same temperature of 665 K and pressure of 3 MPa with the wall heated at 580 W. The mass flow rate of n-dedecane increases from 3 to 4 kg/h. In addition, numerical simulations with kinetics mechanisms with and without pyrolysis are conducted and their results of reactive flow fields are compared with each other. The physical properties of the mixture produced by n-dodecane decomposition are evaluated along the tube. The conversion rate of the fuel and the volume of endothermic reaction decreases as the mass flow increases. - COLLAPSE
    31 December 2021
  • Research Article

    Combustion Instability Modeling in a Reverse-Flow Gas Turbine Combustor using a Network Model

    네트워크 모델을 사용한 역류형 가스터빈 연소기에서의 연소불안정 예측

    Juchan Son and Daesik Kim

    손주찬, 김대식

    In this paper, combustion instability in a reverse-flow gas turbine combustor was analyzed using a 1D network model. Two different approaches of … + READ MORE
    In this paper, combustion instability in a reverse-flow gas turbine combustor was analyzed using a 1D network model. Two different approaches of flame transfer functions were considered; one is a classical n-τ model and the other is a modified model considering the time delay distribution. As a result of constructing a network model by rearranging acoustic elements in the flow direction, the analysis results of frequency and mode distribution similar to the measurement were obtained. In addition, the feedback instability prediction results considering the time delay distribution have shown modeling results closer to the experiment compared to the classical n-τ model. - COLLAPSE
    31 December 2021
  • Research Article

    Analysis of Turbulent Premixed Flames in V-shape Flames with Fractal Turbulence Generators : Part. III Turbulent Burning Velocity

    프랙탈 난류생성판을 갖는 V-shape 화염에서 난류 예혼합 화염 분석 : Part. III 난류 연소속도

    Juhan Kim and Keeman Lee

    김주한, 이기만

    This study focused on calculating the turbulent flame speed in a V-shape turbulent premixed flame using a circular fractal turbulence generator. In … + READ MORE
    This study focused on calculating the turbulent flame speed in a V-shape turbulent premixed flame using a circular fractal turbulence generator. In previous studies [Part. I turbulent flow characteristics in a Non-Reacting Field], [Part. II characteristics of turbulent flame structures], the non-reactive turbulent flow and turbulent flame structure for the V-shape flame of a fractal turbulence generator were investigated in detail. Two types of turbulent burning velocities are evaluated : local displacement and consumption speeds. The local consumption speed is calculated via the image processing of flame surface density. The results show that turbulent burning velocity increases much with fractal grids as compared with the conventional grids perforated plate and mesh. Finally, it was confirmed that the correlation between the turbulent flow factor and the two turbulent burning velocities of each turbulence generator was collapsed well with a specific correlation equation. - COLLAPSE
    31 December 2021
  • Research Article

    Conditional Flamelet Structure and Burning Velocity of Turbulent Premixed Flames

    조건 평균법에 의한 난류 예혼합 화염편 구조와 전파 속도 예측

    Yeongdo Park and Kang Y. Huh

    박영도, 허강열

    A governing equation is derived from the equation of the reaction progress variable for the conditional flamelet structure and the turbulent burning … + READ MORE
    A governing equation is derived from the equation of the reaction progress variable for the conditional flamelet structure and the turbulent burning velocity in turbulent premixed combustion. Direct numerical simulations are conducted for constant density flames to validate the newly derived conditional flamelet equation. Good agreement is shown between the conditional flamelet equation and the flamelet structures and turbulent burning velocities from DNS. They are validated for laboratory flames as well by numerical solutions of the modified laminar premixed flame code in Cantera. Reasonable agreement is shown with a tuning constant for turbulent diffusivity to consider the uncertainty involved in each experimental setup and conditions in the references. - COLLAPSE
    31 December 2021