한국연소학회지 · 한국연소학회

Research Article

Investigation of Nitrogen Oxides Reduction Characteristics in Methane Swirl Flames under Varying Oxidizer Compositions
메탄 스월 화염에서 산화제 조성 변화에 따른 질소산화물 저감 특성 연구

Silvia Kim, Hyungrok Do
김실비아, 도형록

Emissions of nitrogen oxides (NOx) from high-temperature combustion remain a major concern because thermal NOx formation increases sharply with temperature. This study … + READ MORE

Emissions of nitrogen oxides (NOx) from high-temperature combustion remain a major concern because thermal NOx formation increases sharply with temperature. This study proposes a nitrogen-dilution-based oxidizer composition control strategy inspired by membrane air separation, in which the nitrogen fraction is increased and oxygen concentration reduced without burner modification or active control. Experiments were conducted using a premixed methane-air swirl burner at atmospheric pressure under three oxidizer conditions, and NOx emissions were evaluated as EINOx. Flame structure was analyzed using CH^* chemiluminescence imaging with inverse Abel transform to estimate flame volume and residence time. Under constant fuel flow, nitrogen dilution reduced NOx by up to 45% in concentration and 26% in EINOx due to reduced oxygen concentration and lower adiabatic flame temperature. Overall, the results demonstrate the effectiveness of oxidizer composition control as a practical NOx reduction strategy. - COLLAPSE

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31 March 2026
Research Article

Laminar Flame Analysis of Steel Off-Gases and Ammonia Co-firing
제철 부생가스 암모니아 혼소의 층류 화염 특성 분석

Kyeong-Ho Kim, Byoung-Hwa Lee, Chung-Hwan Jeon
김경호, 이병화, 전충환

To achieve carbon neutrality in the steel industry, co-firing ammonia (NH₃) with steel mill off-gases, specifically coke oven gas (COG) … + READ MORE

To achieve carbon neutrality in the steel industry, co-firing ammonia (NH₃) with steel mill off-gases, specifically coke oven gas (COG) and blast furnace gas (BFG), has emerged as a promising decarbonization strategy. This numerical study investigates the combustion characteristics of co-firing NH₃ with COG and BFG. Using the Okafor mechanism, laminar burning velocities and NOx emissions were analyzed. Results indicate that COG, NH₃ co-firing reduces laminar burning velocity due to radical competition but increases NOx emissions. Conversely, BFG, NH₃ mixtures exhibit non-linear laminar burning velocity, recovering stability at higher fractions, and demonstrate a significant DeNOx effect with reduced emissions compared to pure NH₃. These findings provide essential data for optimizing co-firing ratios to balance combustion stability and environmental compliance in steel manufacturing. - COLLAPSE

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31 March 2026
Research Article

Numerical Investigation of Regression Rate and Combustion Characteristics of Fuel-Rich Propellant in Ramjet Combustor under Varying Inlet Conditions
램제트 연소기 입구 조건에 따른 연료과농 추진제의 후퇴율 및 연소 특성에 관한 수치해석 연구

Eunchong Kim, Lin Yun, Iksoo Park, Sangwook Jin, Doheon Kim, Jaehoon Ryu, Hanseul Shim, Hyung Sub Sim
김은총, 윤린, 박익수, 진상욱, 김도헌, 류재훈, 심한슬, 심형섭

The regression rate of solid fuel is a critical performance parameter in solid-fuel ramjets, directly influencing thrust, specific impulse, and range. Therefore, … + READ MORE

The regression rate of solid fuel is a critical performance parameter in solid-fuel ramjets, directly influencing thrust, specific impulse, and range. Therefore, accurate prediction of regression rate is essential for the design and optimization of solid-fuel ramjet propulsion systems. In this study, a coupled numerical framework combining condensed-phase pyrolysis and gas-phase combustion was developed to predict the regression rate and combustion characteristics of a fuel-rich propellant for solid-fuel ramjet applications. The regression rate was computed based on convective heat transfer from the flame and the Arrhenius-type pyrolysis relationship. Systematic analysis was conducted to examine the effects of inlet air mass flux and temperature on fuel regression and combustion performance. The predicted regression rate showed good agreement with experimental data, validating the proposed model. The results revealed that the local regression rate peaked near the reattachment point and gradually decreased downstream. Furthermore, increasing the air mass flux and temperature led to a higher regression rate. A regression rate correlation was derived, demonstrating that both air temperature and mass flux significantly influence the fuel regression rate. - COLLAPSE

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31 March 2026
Research Article

Development and Validation of Nitrogen Oxides Formation Mechanism for High-Temperature Conditions Using the Reaction Mechanism Generator (RMG)
Reaction mechanism generator (RMG)를 이용한 고온 환경 질소산화물 합성 메커니즘 생성 및 검증 연구

Woorin Kang, Moon Soo Bak
강우린, 박문수

The detailed reaction mechanism for NO_x formation under high-temperature conditions was generated using the Reaction Mechanism Generator (RMG). The mechanism was … + READ MORE

The detailed reaction mechanism for NO_x formation under high-temperature conditions was generated using the Reaction Mechanism Generator (RMG). The mechanism was generated over 2000–5000 K at 1 bar and included pressure-dependent reactions. The final mechanism consists of 33 species and 292 reactions, including neutral and electronically excited species. To evaluate the generated mechanism, it was implemented in a reduced-order chemical reactor network model that accounts for the flow characteristics of a microwave plasma reactor, and the predicted NO_x concentrations were compared with measurements. The simulations predicted that the NO_x concentration reaches a maximum at N₂:O₂ = 6:4 and 5:5 and decreases with increasing flow rate, consistent with the experimental observations. However, the discrepancy between the simulations and experiments increased as the flow rate increased, which is attributed not to missing reaction pathways but to simplifications in the reactor model that do not fully capture the actual temperature gradient. Reaction path analysis showed that Zeldovich reactions and three-body dissociation of O₂ and NO dominate in the plasma stream. In the surrounding stream, reactions involving O atoms diffusing from the plasma stream are dominant, with O-atom recombination to form O₂ and NO–NO₂ interconversion as the main pathways. Additionally, reactions involving electronically excited species derived from the pressure-dependent reactor were also identified. However, these excited species did not contribute to NO_x formation and instead relaxed back to their ground state via collisional relaxation. - COLLAPSE

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31 March 2026
Research Article

Analysis of Exhaust Emission Characteristics of Surrogate e-Gasoline under Various Driving Modes
차대 동력계에서 주행모드에 따른 모사 합성가솔린의 배출 특성 분석

Jeonghyun Park, Naeun Choi, Hyung Jun Kim, Sangki Park, Young-Kyo Seo, Suhan Park
박정현, 최나은, 김형준, 박상기, 서영교, 박수한

The objective of this study is to investigate the exhaust emission characteristics of surrogate e-gasoline fuels reflecting Fischer–Tropsch synthetic fuel properties under … + READ MORE

The objective of this study is to investigate the exhaust emission characteristics of surrogate e-gasoline fuels reflecting Fischer–Tropsch synthetic fuel properties under real vehicle and chassis dynamometer conditions. Three surrogate e-gasoline blends were formulated and compared with conventional gasoline using four standard driving cycles (FTP-75, HWFET, SC03, and US06). Regulated emissions (CO₂, NOₓ, THC, and CO) and unregulated pollutants, including volatile organic compounds (VOCs) and carbonyl compounds, were simultaneously evaluated. The results show that surrogate e-gasoline fuels produce higher THC and CO emissions during cold-start conditions due to delayed fuel vaporization associated with lower vapor pressure. However, under stabilized and high-temperature operating conditions, improved combustion stability—particularly for fuels with a higher iso-paraffin content—leads to reduced THC and CO emissions compared to gasoline. Fuels containing MTBE exhibit a slight increase in NO_x owing to elevated combustion temperatures, while overall CO₂ emissions are reduced by approximately 3% as a result of higher heating value. In addition, the removal of aromatic hydrocarbons effectively suppresses hazardous VOC emissions such as benzene and toluene. - COLLAPSE

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31 March 2026
Research Article

Analysis of Initial Flame Structure and Pressure Evolution in a Pre-Detonator under Varying Equivalence Ratios
당량비에 따른 Pre-detonator 초기 화염 구조 및 압력 거동 특성 분석

Myeung Hwan Choi, Yuchang Gil, Sungwoo Park, Jungtae Cho, Taeha Kwon
최명환, 길유창, 박성우, 조정태, 권태하

This study experimentally investigates the ignition characteristics of a methane–air pre-detonator under varying equivalence ratios using ultra-high-speed visualization and dynamic pressure measurements. … + READ MORE

This study experimentally investigates the ignition characteristics of a methane–air pre-detonator under varying equivalence ratios using ultra-high-speed visualization and dynamic pressure measurements. The ignition process was divided into initial ignition, secondary ignition induced by reflected shock waves, and exhaust stages. High-speed imaging showed that flame wrinkling increased with equivalence ratio, which is attributed to enhanced burning velocity, higher heat release rate, and intensified pressure rise under confined conditions. After passing through the DDT (deflagration-to-detonation transition) device, distinct Von-Neumann spikes were observed at downstream pressure sensors, indicating successful detonation transition. Although reflected shock waves induced secondary combustion within the chamber, their influence on transition behavior became limited once a sufficiently strong detonation wave was established. Quantitative analysis revealed that flame residence time decreased significantly with increasing equivalence ratio and approached a minimum threshold beyond unity. These results demonstrate that ignition behavior in a confined pre-detonator is governed by coupled effects of pressure rise, shock–flame interaction, and fuel–air ratio. - COLLAPSE

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31 March 2026

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Journal Informaiton

Journal of the Korean Society of Combustion

Journal of the Korean Society of Combustion

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