Combustion and Flame最新文献

{"title":"Radiative characterization detection and mechanism analysis of soot generation and oxidation during coal combustion based on hyperspectral and mid-wave infrared imaging techniques","authors":"Ke Chang,&nbsp;Meng Liu,&nbsp;Zixue Luo,&nbsp;Qiang Cheng","doi":"10.1016/j.combustflame.2025.114177","DOIUrl":"10.1016/j.combustflame.2025.114177","url":null,"abstract":"<div><div>The generation of soot during coal combustion is closely related to tar, and the incomplete combustion product soot competes with the complete oxidation product CO₂ during the combustion process. In this study, the light volatiles of coal particles are experimentally precipitated to obtain tar coal, and the simultaneous measurement of soot and CO₂ radiation characteristics is achieved by combining hyperspectral (HSI) and mid-wave infrared (MWIR) imaging technologies. Furthermore, the inherent competitive mechanism between the generation and oxidation of polycyclic aromatic hydrocarbons (PAHs) is revealed through mechanistic analysis. As the core structure of soot, PAHs have complex and diverse generation pathways. A1 is formed through both the C3 pathway involving odd-carbon atoms and the C2+C4 pathway involving even-carbon atoms. The generation of A2 to A4 is closely related to direct addition reactions on the benzene ring, and tar coal combustion corresponds to a higher generation rate of PAHs. The generation of soot and CO₂ during coal combustion is not sequential, but exists as a competitive relationship throughout the whole process. The experimental validation results show that the soot volume fraction from coal combustion ranges from 5 ppm to 20 ppm, and the CO₂ concentration ranges from 10 % to 25 %, with tar coal combustion corresponding to a higher content of soot and CO₂. Although the mole fraction of soot is much smaller than that of CO₂, solid soot particles have a more significant radiative capacity in terms of emission and absorption, with the spectral radiative intensity of soot being an order of magnitude higher than that of CO₂ during the stable combustion stage.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"276 ","pages":"Article 114177"},"PeriodicalIF":5.8,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143816677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Macrostructure and ultraviolet chemiluminescence of NH3/H2/Air swirling micromix flames","authors":"Can Cao ,&nbsp;Linyao Zhang ,&nbsp;Chang Xing ,&nbsp;Li Liu ,&nbsp;Penghua Qiu ,&nbsp;Shaozeng Sun","doi":"10.1016/j.combustflame.2025.114170","DOIUrl":"10.1016/j.combustflame.2025.114170","url":null,"abstract":"<div><div>This study investigates the macrostructure and ultraviolet chemiluminescence of NH₃/H₂/Air flames using a novel single-nozzle micromix swirl burner at relatively wide ranges of hydrogen mixing ratio (30 %≤<em>X</em>_H2≤70 %) and equivalence ratio (0.4≤<em>φ</em>≤1.3). The transition of flame macrostructure and its relationship with the ultraviolet spectrum is revealed in detail. The flame macrostructure transition was observed as the equivalence ratio increased at different hydrogen mixing ratio studied in this work. The chemiluminescence intensity and intensity ratios of selected emission peaks within the wavelength range of 200∼400 nm showed that the <em>Overlap</em> part (275–302 nm) is important for indicating the characteristics of NH₃/H₂/Air micromix flames. The normalized peak height at wavelength of 296 nm in the <em>Overlap</em> part is quite sensitive to the NH₃/H₂ mixing fraction and insensitive to the equivalence ratio, making it a useful indicator for predicting the hydrogen ratio in the NH₃/H₂ mixed fuels. The NO*/<em>Overlap</em> and NH*/<em>Overlap</em> ratios can be used to predict the equivalence ratio of NH₃/H₂/Air micromix flames when the hydrogen ratio is known. Additionally, turning points were found along the chemiluminescence intensity ratio curves (as a function of equivalence ratio), which could well match the critical equivalence ratio for the macrostructure transition from “V” to “M” at different hydrogen ratios.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"276 ","pages":"Article 114170"},"PeriodicalIF":5.8,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143807807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Catalytic and gas-phase combustion of SOFC off-gases over platinum surfaces: an experimental and numerical investigation at pressures up to 8 bar","authors":"Vinoth K. Arumugam ,&nbsp;Ulrich Doll ,&nbsp;John Mantzaras","doi":"10.1016/j.combustflame.2025.114167","DOIUrl":"10.1016/j.combustflame.2025.114167","url":null,"abstract":"<div><div>The combustion of low calorific value Solid Oxide Fuel Cell (SOFC) off-gases was investigated in a platinum-coated channel-flow reactor, at pressures 1–8 bar and surface temperatures 700–1060 K. H₂/CO/H₂O/CO₂/Air mixtures were used at a global equivalence ratio <em>φ</em> = 0.90, with compositions relevant to either high- or low-FUR (Fuel Utilization Rate) operation of the SOFC. Spatially resolved, in situ Raman measurements of main gas-phase species concentrations evaluated the catalytic (heterogeneous) reactivity, while Planar Laser Induced Fluorescence of the OH radical monitored gas-phase (homogeneous) combustion. Two-dimensional numerical simulations were carried out with detailed heterogeneous and homogeneous chemical reaction mechanisms. Under high-FUR operation, the lower contents of H₂ and CO favored catalytic ignition as they diminished the chemical self-inhibition that both fuels exhibited on Pt. High pressures were beneficial due to the positive pressure dependence of both H₂ and CO reactivities on Pt. For the typically high temperatures of the SOFC off-gases (&gt; 700 K), catalytic ignition was readily achieved, whereas gaseous chemistry was negligible in all high-FUR cases. For the low-FUR cases with much higher H₂ contents, the H₂ preferential diffusion rendered O₂ locally the deficient surface reactant, despite the globally fuel-lean stoichiometry, resulting in reduced H₂ and CO conversions. By increasing the surface temperatures in the low-FUR cases to ∼1100 K, homogeneous combustion was ignited for pressures <em>p</em> ≥ 3 bar. Upon homogeneous ignition, the flames did not stabilize inside the reactor but propagated upstream and anchored at the channel entry. This resulted in an inverse catalytically stabilized hybrid combustion concept, wherein a downstream catalytic section served as an igniter and stabilizer for an upstream homogeneous combustion zone. This concept was advantageous, as it permitted complete consumption of H₂ and CO via homogeneous reactions at appreciably shorter reactor lengths.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"276 ","pages":"Article 114167"},"PeriodicalIF":5.8,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143816676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphing flames and localized hot spots: Unlocking the dynamics of deflagration-to-detonation transition in curved channels","authors":"Suwei Sun,&nbsp;Zhenhua Pan","doi":"10.1016/j.combustflame.2025.114169","DOIUrl":"10.1016/j.combustflame.2025.114169","url":null,"abstract":"<div><div>This study presents a systematic experimental investigation into the flame propagation and deflagration-to-detonation transition (DDT) processes within curved channels, with a particular focus on the influence of initial pressure and geometric parameters (inner and outer radii). The experimental setup, featuring a 270° curved channel and utilizing stoichiometric ethylene-oxygen mixtures as the fuel, employed high-speed camera to capture flame dynamics and pressure transducers to monitor pressure wave distributions. The results demonstrate that the geometric characteristics of the curved channel significantly modulate flame acceleration, with smaller outer radii and larger inner radii markedly enhancing flame acceleration and reducing the time required for DDT (<em>t</em>_DDT). The initial pressure emerges as a key parameter governing the spatial distribution of hot spots and the onset of detonation. Higher initial pressures drive hot spots toward the flame front, accelerate energy accumulation, and significantly improve DDT efficiency. The experimental findings demonstrate that hot spots exclusively form near the outer wall of the channel, a phenomenon attributed to localized high-temperature and high-pressure regions induced by the interaction between the leading shock wave and the outer wall. Under varying initial pressures, hot spots exhibit three distinct spatial distribution patterns: (1) at the root of the tongue-shaped flame, (2) at the tip of the tongue-shaped flame, and (3) simultaneously at both the root and tip. Notably, the presence of flame front wrinkles at the tip of the tongue-shaped flame is identified as a key feature in the latter two patterns, playing a dominant role in hot spot formation. Quantitative analysis further reveals a positive correlation between the characteristic length of the tongue-shaped flame at the moment of the hot spot formation and <em>t</em>_DDT. This finding highlights the synergistic interplay between the geometric properties of the curved channel and initial conditions in determining the efficiency and characteristics of the DDT process. Collectively, this study provides critical experimental insights and theoretical support for understanding the complex physical mechanisms underlying flame propagation and detonation transition in curved channels, offering valuable implications for optimizing combustion dynamics in geometrically complex systems.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"276 ","pages":"Article 114169"},"PeriodicalIF":5.8,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143807808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of oxygen concentration on thermal oxidation and combustion characteristics of single aluminum particles","authors":"Xueqin Liao ,&nbsp;Peihui Xu ,&nbsp;Mengxia Sun ,&nbsp;Fan Zhang ,&nbsp;Jianzhong Liu","doi":"10.1016/j.combustflame.2025.114166","DOIUrl":"10.1016/j.combustflame.2025.114166","url":null,"abstract":"<div><div>Aluminum (Al) particles are widely used in propellants, thermite and explosives. However, its energy release process is still not thoroughly investigated. In this paper, the reaction properties of Al particles at low and high heating rates were investigated using a thermal analysis system and a single-particle combustion system, respectively. At a low heating rate (10°C/min), when the temperature is raised to 1200°C, the oxidation efficiency of Al (which can also be regarded as the average oxidation rate) increases first and then decreases as the oxygen concentration increases. In addition, XRD results of intermediate oxidation products under air show that the oxidation of Al particles deepens with increasing temperature. The SEM results reveal that broken particles and large-size aggregates gradually appear in the sample as the temperature increases, and the surface of the Al particles becomes rougher. At high heating rate (combustion), with the increase of oxygen concentration, the probability of microexplosion of Al particles increases from 19.77 % under air to 82.67 % under 100 % O₂. Furthermore, the combustion time gradually decreases with the increase of oxygen concentration, while the average mass burning rate gradually increases from 1.65 g/ms under air to 2.73 g/ms under 100 % O₂. Based on the analysis of the surface structure of the intermediate oxidation products and the microexplosion of single particles, it is believed that the difference of the reaction law of Al particles at different heating rates may be related to the structural evolution behavior of the oxide film. This study provides basic data support for understanding the heat release behavior of Al particles.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"276 ","pages":"Article 114166"},"PeriodicalIF":5.8,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143807806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimizing progress variables for ammonia/hydrogen combustion using encoding–decoding networks","authors":"Kamila Zdybał ,&nbsp;James C. Sutherland ,&nbsp;Alessandro Parente","doi":"10.1016/j.combustflame.2025.114152","DOIUrl":"10.1016/j.combustflame.2025.114152","url":null,"abstract":"<div><div>We demonstrate a strategy to optimize parameterizations of combustion manifolds using an encoding–decoding artificial neural network architecture. Our focus in this work is on the combustion of ammonia (NH3) and hydrogen (H2) blends. The literature on NH3 combustion, to date, lacks an efficient definition of a reaction progress variable (PV) to parameterize the thermo-chemical state-space. A quality parameterization should be able to represent the thermo-chemical state variables accurately, as well as any functions of those, <em>e.g.</em>, the source terms of the non-conserved PVs. Our approach incorporates information about the reaction source term of a PV and about important combustion products into the PV optimization. A gradient descent optimizer is informed by the reconstruction quality of those important quantities of interest (QoIs) that enter the optimization as decoder outputs. The approach can be thought of as an iterative back-and-forth between defining a parameterization (encoding) and reconstructing QoIs from it (decoding). It thus naturally promotes parameterizations where each QoI is uniquely and smoothly represented over the manifold. This work can help advance the adaptivity of combustion models. First, we show that with an adequate definition of a PV, we can steer the model’s accuracy towards improved representation of selected products and pollutants. Second, the definition of a PV automatically adapts to best complement the remaining physics-based parameters, such as the mixture fraction or the enthalpy defect. These two achievements combined were not possible with the existing PV optimization methods which only impose monotonicity and scalar gradient magnitude in defining a PV.</div><div><strong>Novelty and Significance Statement</strong></div><div>We demonstrate a novel strategy to optimize the definition of a progress variable (PV) using an encoding–decoding artificial neural network. Our approach can be thought of as an iterative back-and-forth between defining a parameterization of a flame (encoding) and reconstructing important scalars from it (decoding). Notably, the PV definition and its corresponding source term are co-optimized. The definition of a PV automatically adapts to best complement the remaining physics-based parameters, such as the mixture fraction or the enthalpy defect. These achievements were not possible with the existing PV optimization methods which only impose monotonicity and scalar gradient magnitude in defining a PV. This work can help advance combustion models, paving the way for adaptive reduced-order models, where the model can be adjusted towards particularly good representation of target scalars, such as pollutants. Our optimization method is applicable to premixed and non-premixed combustion.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"276 ","pages":"Article 114152"},"PeriodicalIF":5.8,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143807809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Publication / Copyright Information","authors":"","doi":"10.1016/S0010-2180(25)00194-4","DOIUrl":"10.1016/S0010-2180(25)00194-4","url":null,"abstract":"","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"275 ","pages":"Article 114156"},"PeriodicalIF":5.8,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143808450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study of hydrodynamic instabilities in laminar normal and inverse diffusion flames under elevated pressures","authors":"Raul Serrano-Bayona ,&nbsp;Tao Yang ,&nbsp;Peng Liu ,&nbsp;Xuren Zhu ,&nbsp;Carson Chu ,&nbsp;Ibrahim Alsheikh ,&nbsp;William L. Roberts","doi":"10.1016/j.combustflame.2025.114165","DOIUrl":"10.1016/j.combustflame.2025.114165","url":null,"abstract":"<div><div>Understanding hydrodynamic instabilities in coflow diffusion flames is essential for enhancing operational stability and safety. This study presents the first experimental investigation into the effects of pressure, flow rates, coflow/central jet velocity ratio, and O₂ concentration on hydrodynamic instabilities in laminar normal and inverse diffusion flames (NDFs and IDFs). Methane (CH₄) diluted with carbon dioxide (CO₂) was used as fuel, whereas oxygen (O₂) diluted with nitrogen (N₂) was the oxidant. The spatial-temporal features of these flames were captured with a high-speed camera, luminous flame height was characterized for flame dynamics, and oscillation frequency was quantified using the Fast Fourier Transform (FFT) method. Results demonstrate that flame configuration significantly influenced instability modes. Unstable NDFs consistently exhibited the sinuous mode, while unstable IDFs were predominantly under the varicose mode. This distinct trend could be attributed to the density difference between the central jet and the coflow stream. Instability modes are found to be highly sensitive to the gas velocity and O₂ concentration since these parameters could displace the point of toroidal vortices formation (upward displacement with higher coflow velocity and lower jet velocity) and affect the flame height (reduction at lower jet velocity or higher O₂ concentration). Pressure had a minimal effect on the instability modes, although stable flames were mostly observed at higher pressures with high <span><math><mrow><mi>R</mi><msub><mi>e</mi><mrow><mi>c</mi><mi>o</mi><mi>f</mi><mi>l</mi><mi>o</mi><mi>w</mi></mrow></msub></mrow></math></span>. Instead, oscillation frequency increased with pressure in buoyancy-driven flames (<span><math><mrow><mi>F</mi><mi>r</mi><mo>&lt;</mo><mn>1</mn></mrow></math></span>) but was more influenced by jet flow rate in momentum-driven flames (<span><math><mrow><mi>F</mi><mi>r</mi><mo>&gt;</mo><mn>1</mn></mrow></math></span>). A power-law relationship between the non-dimensional numbers <span><math><mrow><mi>S</mi><mi>t</mi></mrow></math></span> and <span><math><mrow><mi>F</mi><mi>r</mi></mrow></math></span> was observed with two different slopes for momentum-driven flames (<span><math><mrow><mi>n</mi><mspace></mspace><mo>&lt;</mo><mspace></mspace><mn>0.5</mn></mrow></math></span>) and for buoyancy-driven flames (<span><math><mrow><mi>n</mi><mspace></mspace><mo>&gt;</mo><mspace></mspace><mn>0.5</mn></mrow></math></span>). A single correlation with Re described frequency behavior at each pressure level. These findings offer practical conditions for optimizing ATR burner stability.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"276 ","pages":"Article 114165"},"PeriodicalIF":5.8,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interdisciplinary combustion issues in electrically controlled solid propellant","authors":"Zhiwen Wang ,&nbsp;Feng Li ,&nbsp;Lian Li ,&nbsp;Keer Ouyang ,&nbsp;Ruiqi Shen ,&nbsp;Yinghua Ye ,&nbsp;Luigi T. DeLuca ,&nbsp;Wei Zhang","doi":"10.1016/j.combustflame.2025.114145","DOIUrl":"10.1016/j.combustflame.2025.114145","url":null,"abstract":"<div><div>A novel rocket fuel for intelligent solid propulsion system, electrically controlled solid propellant (ECSP), with on-demand on-off capacity and programmable thrust output characteristics, is attracting substantial attention due to conquering the inherent self-sustaining combustion defect of traditional solid propellant. Regrettably, the coupling effects of the external physical energy field, pressure, and electrochemistry have compounded the complexity of combustion chemistry, hindering the technology from gaining widespread support. Herein, the comprehensive combustion characteristics (involving ignition/extinguishment delay, burning rate, mass loss, and dynamic-diffusion flame transition) of propellant was investigated with synchronous elevating pressure and voltage, utilizing a lab-designed high-pressure electrically controlled combustion diagnosis system. Importantly, we proposed a seminal voltage-dominated dual-index burning rate model (<span><math><mrow><mi>r</mi><mo>=</mo><mi>a</mi><msup><mrow><mo>(</mo><mrow><mi>f</mi><mo>(</mo><mi>U</mi><mo>)</mo></mrow><mo>)</mo></mrow><msub><mi>n</mi><mn>1</mn></msub></msup><msup><mrow><mi>p</mi></mrow><msub><mi>n</mi><mn>2</mn></msub></msup></mrow></math></span> (<span><math><mrow><mn>0</mn><mo>&lt;</mo><msub><mi>n</mi><mn>1</mn></msub><mo>=</mo><mn>0.8081</mn><mo>,</mo><msub><mi>n</mi><mn>2</mn></msub><mo>=</mo><mn>0.1427</mn><mo>&lt;</mo><mn>1</mn></mrow></math></span>)) through the electrode-interface heterogeneous reaction kinetics, demonstrating that the burning rate can be precisely regulated by the active voltage-control without compromising the operation stability of solid rocket motor (SRM). Targeted investigation of the interface evolution revealed hyperthermic interface could trigger self-sustaining combustion.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"276 ","pages":"Article 114145"},"PeriodicalIF":5.8,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"N2O reduction with selective excitation of species by non-equilibrium plasma in an NH3/air mixture","authors":"Nan Liu ,&nbsp;Qi Chen ,&nbsp;Xingyu Lu ,&nbsp;Jiaying Pan ,&nbsp;Haiqiao Wei ,&nbsp;Xingqian Mao","doi":"10.1016/j.combustflame.2025.114164","DOIUrl":"10.1016/j.combustflame.2025.114164","url":null,"abstract":"<div><div>Non-equilibrium plasma can enhance NH₃ combustion and simultaneously decrease N₂O/NO_x emissions at low temperatures. This study proposes a method of selective excitation of specific species in an NH₃/air mixture, such as O₂, N₂, air, or NH₃, to assess the effects for decreasing N₂O concentrations in the non-equilibrium plasma-assisted NH₃ oxidation via numerical modeling. The selective excitation is realized by removing the electron impact reactions and chemical reactions involving excited species apart from the target species. The results demonstrate that the selective excitation of specific species can significantly reduce N₂O concentrations compared with plasma-excited NH₃/air mixtures at low temperatures. Specifically, the optimal N₂O emission reduction at 800 K is achieved with plasma excitation of O₂. Due to the absence of interactions between NH₃ and electron/electronically excited state species N₂* and N(²D), the concentrations of NH/NH₂ radicals contributing to N₂O production dramatically decrease. Meanwhile, the primary N₂O consumption pathway becomes more prominent due to the efficient production of O(¹D). The reaction rate of the main N₂O production pathway is 1–2 orders of magnitude lower than that of the NH₃/air mixture. This work offers valuable insight and guidance for combustor design in advanced engines to effectively reduce N₂O emissions by using non-equilibrium plasma.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"276 ","pages":"Article 114164"},"PeriodicalIF":5.8,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}