• Research Article

    Prediction of MILD Combustion Characteristics and NOx Formation for Ammonia Conversion and Flue Gas Recirculation

    암모니아 전환 및 배가스 재순환에 따른 MILD 연소 특성 및 NOx 생성에 대한 예측 연구

    Jiho Yu, Jongsup Hong, Youngjae Lee

    유지호, 홍종섭, 이영재

    Many researchers are encouraging efforts to reduce greenhouse gas emissions. To achieve this, it is necessary to reduce the use of hydrocarbon-based … + READ MORE
    Many researchers are encouraging efforts to reduce greenhouse gas emissions. To achieve this, it is necessary to reduce the use of hydrocarbon-based fuels or switch to carbon-free fuels. Ammonia can be one of transport methods of hydrogen. Transported ammonia can be used to extract hydrogen through decomposition or directly as a fuel. The purpose of this study is to nummerically analyze the MILD combustion characteristics and NOx emission of hydrogen-ammonia-nitrogen mixtures. Numerical simulations were performed by 0D Homogeneous model and 1D OPPDIF model of Chemkin. The target fuel was assumed to be the tail gas generated by the ammonia decomposition, and the composition of fuels was defined through the ammonia conversion rate(CR) of 0-100%. The results showed that MILD combustion was achieved when the flue gas recirculation rate was increased or the ammonia content was high. As the recirculation rate increased, the region of maximum heat release rate merged into one. Moreover, the NO emission decreased while the N2O emission increased. This means that NO and N2O are formed by the routes of Thermal NOx and Fuel NOx, respectively. A future work will include experimental studies of MILD combustion characteristics in terms of ammonia content in a lab-scale MILD combustion system. - COLLAPSE
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    30 June 2023

  • Research Article

    Study on Zero Carbon Fuels for Gas Turbine Application

    무탄소 연료의 가스터빈 적용 특성에 관한 연구

    Jaemin Lee, Eun-Seong Cho

    이재민, 조은성

    This study examines the co-firing characteristics of a zero-carbon fuel based on methane gas (CH4) with hydrogen (H2) … + READ MORE
    This study examines the co-firing characteristics of a zero-carbon fuel based on methane gas (CH4) with hydrogen (H2) and ammonia (NH3) by means of numerical simulation using ANSYS CHEMKIN-Pro and the performance analysis tool Ebsilon. Four different co-firing conditions are analyzed, namely, pure H2, pure NH3, 100% NH3 full cracking fuel (75% H2 + 25% N2), and partial (60%) NH3 cracking fuels. Adhering to identical adiabatic flame temperature values across all co-firing conditions, we maintain the same TIT (Turbine Inlet Temperature) for calculation purposes. Notably, a slight increase in NH3 fuel composition leads to elevated fuel NOx, presenting an obstacle in applying premixed-type gas turbine combustion. Cycle analysis results demonstrate that power output and efficiency increase as the blending ratio is raised, with significant disparities among the blending fuels. - COLLAPSE
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    30 June 2023

  • Technical Notes

    Comparisons of Flame Stretch Calculation Models and Their Applications Part I: Model Comparisons

    화염 스트레치 계산 모델들의 비교와 적용 I: 모델 비교

    Yong Jea Kim, Dong-hyuk Shin

    김용제, 신동혁

    Invariant forms of the flame stretch on three dimensional flame surfaces were derived by M. Matalon (1983), S. H. Chung and C. … + READ MORE
    Invariant forms of the flame stretch on three dimensional flame surfaces were derived by M. Matalon (1983), S. H. Chung and C. K. Law (1984), and S. M. Candel and T. J. Poinsot (1990) respectively in different forms. To resolve potential confusions, the three model forms were compared, and their mutual identities were described in this study. The respective model equations were also organized in their decomposed expressions, by normal and tangential stretch components and by components induced by flow velocity and flame speed. Their applications into numerical and experimental data were discussed, and potential application issues were addressed by illustrating flame stretch calculation procedures. In most situations, necessary parameters (e.g., flame location, migration velocity, flame speed, flow velocity, etc.) could be extracted from the data on the flame surface. Some model equations require operations covering outside of the flame surface, which could be unknowns to calculate flame stretch. - COLLAPSE
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    30 June 2023

  • Technical Notes

    Comparisons of Flame Stretch Calculation Models and Their Applications Part II: Model Applications

    화염 스트레치 계산 모델들의 비교와 적용 II: 모델 적용

    Yong Jea Kim, Minjun Choi, Kanghwan Kim, Dong-hyuk Shin

    김용제, 최민준, 김강환, 신동혁

    Model equations of the flame stretch on three dimensional stretched flame surfaces were derived by M. Matalon (1983), S. H. Chung and … + READ MORE
    Model equations of the flame stretch on three dimensional stretched flame surfaces were derived by M. Matalon (1983), S. H. Chung and C. K. Law (1984), and S. M. Candel and T. J. Poinsot (1990) respectively in different forms. When applying their models into numerical and experimental data, the necessary parameters (e.g., flame location, flame migration velocity, flame speed, flow velocity, etc.) are mostly extracted on the flame surface from the data. However, their applications may not be straightforward or clear as some forms are quite complex or needs parameters outside of the flame surface. In this study, to resolve these issues, straightforward expressions were provided for one dimensional circular and spherical flame, and two dimensional steady and unsteady flames. As illustrations, the flame stretches and their constituent terms were evaluated for two dimensional steady and unsteady laminar flames. - COLLAPSE
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    30 June 2023

  • Research Article

    Study on Combustion Characteristics of Multi-tube H2 Nozzles

    Multi-tube 형 수소 전소 노즐의 연소 특성 연구

    Youngjun Shin, Cheahong Choi, Hanjin Jeong, Seonghwi Jo, Eun-Seong Cho

    신영준, 최채홍, 정한진, 조성휘, 조은성

    Doosan is currently developing a 100% hydrogen gas turbine combustor with a micro-mixer concept multi-tube type nozzle, which has the ability to … + READ MORE
    Doosan is currently developing a 100% hydrogen gas turbine combustor with a micro-mixer concept multi-tube type nozzle, which has the ability to prevent flash-back phenomena during operation. This combustor is intended to replace the existing natural gas firing combustor for 5 MW, and has also been designed to achieve low NOx emissions through the utilization of premixed methods. Our testing has shown that the nozzle provides an expanded operating range through lean blow off and flame holding flash back tests. Going forward, we plan to continue improving and testing the nozzle in real geometry under high-pressure conditions. - COLLAPSE
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    30 June 2023

  • Technical Notes

    Numerical Aspects of Noise-Induced Dynamics in Continuous Combustion Systems

    연속 연소 시스템의 소음 기반 동역학적 거동에 관한 수치적 고찰

    Minwoo Lee

    이민우

    Combustion systems are exposed to intrinsic and extrinsic noise arising from various sources. Contrasting the conventional viewpoint of treating noise as signal … + READ MORE
    Combustion systems are exposed to intrinsic and extrinsic noise arising from various sources. Contrasting the conventional viewpoint of treating noise as signal contamination, the stochastic effects on combustion systems, namely the noise-induced dynamics (NID), are attracting much attention. This is because noise can alter the system's dynamics from the nonlinear interactions with the reacting flow field. Because such an alteration in combustion dynamics cannot be analyzed in a traditional deterministic framework, many studies have been conducted to quantitatively and qualitatively analyze the noise-driven behaviors in combustion systems. In this paper, review the various types of noise-induced dynamics in continuous combustion systems along with the low-order numerical simulations and summarize how such dynamics are used to analyze the physical nature of the system. Specifically, we investigate the ▲phenomenological aspects of the NID in combustion systems, ▲NID used for the diagnosis of such systems, and ▲system identification of combustion systems using the NID. - COLLAPSE
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    30 June 2023
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Journal Informaiton Journal of The Korean Society Combustion Journal of The Korean Society Combustion
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