Combustion and FlamePub Date : 2025-10-11DOI: 10.1016/j.combustflame.2025.114520
Peng Ma , Shumeng Xie , Jinzhou Li , Samir B. Rojas Chavez , Hao Hu , Huangwei Zhang
{"title":"Extinction limit and NO/N2O formation of methanol/ammonia counterflow diffusion flames under elevated conditions","authors":"Peng Ma , Shumeng Xie , Jinzhou Li , Samir B. Rojas Chavez , Hao Hu , Huangwei Zhang","doi":"10.1016/j.combustflame.2025.114520","DOIUrl":"10.1016/j.combustflame.2025.114520","url":null,"abstract":"<div><div>To address ammonia’s low reactivity, the interest in co-firing with methanol, a conventional green transportation fuel in internal combustion engines, is steadily growing. However, the effects of methanol on ammonia flame extinction and NO<sub><em>x</em></sub> are unknown. In this study, we examine the influence of methanol addition on ammonia flame stability under elevated conditions, based on the counterflow diffusion flame via numerical simulations using detailed chemical kinetics and chemical explosive mode analysis. Our analysis shows that methanol addition significantly extends extinction strain rate and introduces a two-stage explosive mode structure under high strain rate conditions. At 1 atm, a small methanol addition (energy fraction of CH<sub>3</sub>OH in fuels E<sub>CH3OH</sub>=5%) increases the extinction strain rate by 13%, and with E<sub>CH3OH</sub> = 50%, the extinction strain rate is nearly 4.75 times higher than that of pure ammonia. This is primarily attributed to the enhanced OH radical production, which shows a strong positive correlation with flame extinction limits. Moreover, elevated pressures and oxidizer preheating further expands the extinction strain rate. Pressure effects are primarily linked to increased local heat release rate despite lower radical mole fraction. Methanol has minimal influence on the pressure–extinction relationship. Furthermore, methanol blending slightly increases NO formation via enhanced HNO and fuel-N pathways but simultaneously reduces N<sub>2</sub>O emissions due to accelerated radical-driven consumption. Methanol addition significantly alters the radical chemistry by introducing CH<sub>2</sub>OH as a key intermediate, shifting OH formation from the conventional O<sub>2</sub> + H pathway to a new dominant route via O<sub>2</sub> + CH<sub>2</sub>OH → HO<sub>2</sub> → OH. This work provides new insights into the extinction characteristics and nitrogen chemistry of NH<sub>3</sub>/CH<sub>3</sub>OH flames under realistic conditions, supporting the design of cleaner and more efficient ammonia-based energy systems.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"282 ","pages":"Article 114520"},"PeriodicalIF":6.2,"publicationDate":"2025-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263476","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}
Combustion and FlamePub Date : 2025-10-10DOI: 10.1016/j.combustflame.2025.114525
Tenglong Lv , Yifeng Wang , Xin Zhong , Qiang Xu , Jinyang Zhang , Zhandong Wang , Zunqing Zheng , Hu Wang
{"title":"Experimental and kinetic modeling study of ammonia/dimethoxymethane oxidation in a jet-stirred reactor using SVUV-PIMS","authors":"Tenglong Lv , Yifeng Wang , Xin Zhong , Qiang Xu , Jinyang Zhang , Zhandong Wang , Zunqing Zheng , Hu Wang","doi":"10.1016/j.combustflame.2025.114525","DOIUrl":"10.1016/j.combustflame.2025.114525","url":null,"abstract":"<div><div>This study investigates the oxidation characteristics of NH₃/DMM₁ (dimethoxymethane, CH<sub>3</sub>OCH<sub>2</sub>OCH<sub>3</sub>) blended fuels at ND-75(1.5 % NH₃: 0.5 % DMM₁) and ND-50 (1 % NH₃: 1 % DMM₁ (balance O₂/Ar, <em>φ</em> =1)) mixing ratios across a temperature range of 550–1100 K, employing experimental and numerical approaches to elucidate their interaction mechanisms. Experiments were conducted in a jet-stirred reactor (JSR) coupled with synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS), enabling the online detection and quantification of 17 products, including C₀–C₃ small molecules, NH₃, nitrogen oxides, and four rarely reported carbon-nitrogen (C–N) intermediates: HCN, HNCO, CH₃CN, and CH₃NO₂. A detailed kinetic model, comprising 210 species and 1595 elementary reactions, was developed based on experimental data and validated against measured species profiles, demonstrating good predictive accuracy for ignition delay times and intermediate evolution. The results reveal that DMM₁ oxidation generates reactive radicals (e.g., OH, HO₂, CH₃) that enhance NH₃ reactivity, with temperature-dependent shifts in C–N bond formation pathways—favoring CH₃+NO₂=CH₃NO₂ at 870 K and CH₃+NH₂=CH₃NH₂ at 1010 K. These intermediates play a crucial role in shaping the reaction network, providing new insights into the coupled nitrogen-carbon chemistry relevant to low-emission combustion technologies.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"282 ","pages":"Article 114525"},"PeriodicalIF":6.2,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263345","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}
Combustion and FlamePub Date : 2025-10-10DOI: 10.1016/j.combustflame.2025.114531
Shuhao Li , Licheng Zhong , Yihuan Dong , Xianggeng Wei , Shuanghui Xi , Gengqi Liu , Da Yao , Baiyan Wang , Xudong Jia , Xiao Guo , Zhenhua Wen , Quan-De Wang , Jinhu Liang
{"title":"Effects of O2/H2O on RP-3 kerosene ignition and flame propagation: A combined experimental and kinetic modeling study","authors":"Shuhao Li , Licheng Zhong , Yihuan Dong , Xianggeng Wei , Shuanghui Xi , Gengqi Liu , Da Yao , Baiyan Wang , Xudong Jia , Xiao Guo , Zhenhua Wen , Quan-De Wang , Jinhu Liang","doi":"10.1016/j.combustflame.2025.114531","DOIUrl":"10.1016/j.combustflame.2025.114531","url":null,"abstract":"<div><div>Understanding the spontaneous ignition and flame propagation characteristics of RP-3 kerosene in O<sub>2</sub>/H<sub>2</sub>O mixtures is critical for advancing chemical kinetic modeling and optimizing hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>)/kerosene bipropellant rocket engines. This study integrates experimental measurements with kinetic modeling to systematically investigate RP-3 combustion behavior under O<sub>2</sub>/H<sub>2</sub>O atmospheres. Ignition delay times (IDTs) and laminar flame speeds (LFSs) of RP-3 in O<sub>2</sub>/H<sub>2</sub>O environments are quantified using a high-pressure shock tube (HPST) and a constant-volume combustion vessel. Two combustion mechanisms are developed for RP-3/O<sub>2</sub>/H<sub>2</sub>O systems, consisting of a comprehensive reaction mechanism (184 species, 1252 reactions) and a small-scale mechanism (40 species, 121 reactions). The predictive capability and accuracy of these mechanisms are validated through experimental measurements of IDTs and LFSs, ensuring their accurate representation of the combustion performance of RP-3 kerosene in O<sub>2</sub>/H<sub>2</sub>O environments. A comparative analysis with the combustion performance of RP-3 in air under equivalent conditions is also conducted. To unravel the underlying reaction pathways, systematic sensitivity analyses and rate-of-production (ROP) diagnostics are implemented to investigate key reactions and mechanisms affecting IDTs, LFSs, and key species formation. The role of H<sub>2</sub>O in the combustion process of RP-3/O<sub>2</sub>/H<sub>2</sub>O is also investigated, and a preliminary analysis is conducted on the combustion characteristics of RP-3 kerosene under different pyrolysis atmospheres of H<sub>2</sub>O<sub>2</sub>.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"282 ","pages":"Article 114531"},"PeriodicalIF":6.2,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263344","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}
Combustion and FlamePub Date : 2025-10-09DOI: 10.1016/j.combustflame.2025.114507
Chenlin Guo
{"title":"Edge flame dynamics and statistical behavior in premixed hydrogen-air combustion under inert and reactive wall conditions","authors":"Chenlin Guo","doi":"10.1016/j.combustflame.2025.114507","DOIUrl":"10.1016/j.combustflame.2025.114507","url":null,"abstract":"<div><div>This study explores the dynamics and statistical properties of edge flames during the extinction and re-ignition processes in turbulent premixed combustion under statistically stationary Flame-Wall Interaction (FWI) scenarios. Direct numerical simulations (DNS) are used to investigate the role of edge flames in these processes, comparing the behavior of head-on and entrained edge flames under inert and reactive wall conditions. The results reveal that the head-on edge flame primarily governs the flame extinction process, while the entrained edge flame dominates the re-ignition process. This distinction is attributed to the opposite absolute flame speeds: the head-on edge flame exhibits a negative flame speed, while the entrained edge flame has a positive flame speed due to exposure to fresh reactants. The reactive wall significantly influences the entrained edge flame by absorbing radicals, raising the wall temperature, and reducing the wall heat flux due to the suppression of low-temperature radical recombination. Head-on edge flames align with compressive, unstable focus or unstable node–saddle–saddle topologies, whereas entrained edge flames occupy stretching, unstable focus or triple unstable node regimes. These findings highlight the importance of considering edge flame-wall interaction in modeling flame extinction and re-ignition dynamics.</div><div><strong>Novelty and significance</strong></div><div>This study presents a novel analysis of edge flame dynamics in premixed flame-wall interaction (FWI) under inert and reactive wall conditions. It emphasizes the significant differences between head-on and entrained edge flames, focusing on flame dynamics, characteristics, kinetics, and local flow topologies. The findings offer valuable insights into the complex interplay between flow structures and flame orientation, particularly in industrial combustion contexts. This work deepens our understanding of edge flame behavior, with potential applications in enhancing flame stabilization and advancing pollutant control strategies in combustion systems.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"282 ","pages":"Article 114507"},"PeriodicalIF":6.2,"publicationDate":"2025-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263347","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}
Combustion and FlamePub Date : 2025-10-07DOI: 10.1016/j.combustflame.2025.114519
Jiabiao Zou , Congjie Hong , Dario Vassetti , Andre Nicolle , Yasser A Qahtani , Abdullah S. AlRamadan , Emre Cenker , Aamir Farooq
{"title":"Multi-speciation in shock-heated H2−N2OO2 mixtures: Investigation on N2O reduction","authors":"Jiabiao Zou , Congjie Hong , Dario Vassetti , Andre Nicolle , Yasser A Qahtani , Abdullah S. AlRamadan , Emre Cenker , Aamir Farooq","doi":"10.1016/j.combustflame.2025.114519","DOIUrl":"10.1016/j.combustflame.2025.114519","url":null,"abstract":"<div><div>Mitigating greenhouse gas emissions and addressing safety concerns in combustion systems are critical for advancing sustainable energy technologies. Using state-of-the-art multi-species laser absorption techniques, we conducted a comprehensive experimental investigation of the chemical interactions between nitrous oxide (N<sub>2</sub>O) and hydrogen (H<sub>2</sub>) with and without oxygen (O<sub>2</sub>) behind reflected shock waves. Speciation time-histories of N<sub>2</sub>O, NO, H<sub>2</sub>O, and OH, as well as ignition delay times, were measured over a temperature range of 890–1936 K and pressures of 1.16–2.19 bar. These measurements offer a comprehensive understanding of reactants, major pollutants, radicals, and final products for N<sub>2</sub>O<img>H<sub>2</sub>−O<sub>2</sub> system. Our proposed chemical kinetic model, featuring an updated N<sub>2</sub>O<img>H<sub>2</sub> subset, provides enhanced predictability and highlights the interaction chemistry involving N<sub>2</sub>O and H<sub>2</sub>. In contrast, literature models exhibit significant discrepancies, particularly in predicting NO profiles and ignition delay times below 940 K. The experimental data and kinetic analysis reveal distinct reaction regimes characterized by the interplay of radical species (e.g., OH, O and NH) and highlights the pivotal role of N<sub>2</sub>O<img>H<sub>2</sub> interaction chemistry in influencing ignition and reaction dynamics. The hydrogen oxidation chemistry under oxidizer-tailored conditions reveals distinct temperature-dependent behavior. Above 1100 K, ignition is promoted by both the N<sub>2</sub>O + <em>H</em> reactions and the thermal decomposition of N<sub>2</sub>O. In contrast, within the 850–1000 K range, the recombination of N<sub>2</sub>O with H atoms to form HNNO slightly suppresses ignition. By bridging critical knowledge gaps, the findings advance both the fundamental understanding of N<sub>2</sub>O<img>H<sub>2</sub> systems and the development of sustainable energy strategies.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"282 ","pages":"Article 114519"},"PeriodicalIF":6.2,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263343","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}
Combustion and FlamePub Date : 2025-10-07DOI: 10.1016/j.combustflame.2025.114524
Kyuho Van , Anguo Hu , Mariano Rubio , Jung Z. Fang , Bhaskar Sarkar , Tushar K. Bera , Allen A. Aradi , Fokion N. Egolfopoulos
{"title":"Effects of end-gas reactivity on fundamental combustion properties of primary reference fuel blends with ethanol at engine-relevant conditions","authors":"Kyuho Van , Anguo Hu , Mariano Rubio , Jung Z. Fang , Bhaskar Sarkar , Tushar K. Bera , Allen A. Aradi , Fokion N. Egolfopoulos","doi":"10.1016/j.combustflame.2025.114524","DOIUrl":"10.1016/j.combustflame.2025.114524","url":null,"abstract":"<div><div>Accurate fundamental combustion data under engine-relevant conditions for liquid fuels are essential for developing predictive models for large-scale simulations of practical combustion devices. However, in existing literature, such data are non-existent or scarce, due to various experimental complications that the high-pressure and temperature conditions introduce. To overcome these limitations, the present study involved a combined experimental and modeling effort to identify thermodynamic conditions that result in reliable and accurate data for flame propagation and autoignition. The study was carried out using the confined spherically expanding flame method for primary reference fuels and their blends with ethanol, which are relevant to gasoline formulation, and which exhibit low-temperature chemistry. Conditions that result in flames that are free of hydrodynamic instabilities were identified through multi-dimensional direct numerical simulations and were implemented in all experimental measurements. Ignition delay times were measured and modelled, and the effect of ethanol addition was quantified with excellent experimental repeatability and uncertainty. Various kinetic models were used, and the discrepancy between predicted and measured ignition delay times was found to increase with ethanol addition. While end-gas reactivity is essential for autoignition studies, it is undesirable when laminar flame speeds are measured. Such effects can be present at engine-relevant conditions and for the gasoline-relevant fuels considered herein. While it has been shown in modeling studies, the increase of the burning rate due to end-gas reactivity was quantified for the first time experimentally in the present study for selected conditions, emphasizing that proper vetting of laminar flame speed data under high-pressure and temperature conditions is required. Additionally, in modeling spark ignition engines, both low and high temperature kinetic models must be used, not only to capture autoignition but also to properly predict the burning rate.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"282 ","pages":"Article 114524"},"PeriodicalIF":6.2,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263348","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":"Effects of swirl intensity on boundary layer flashback in a confined bluff-body swirl burner","authors":"Weijie Zhang, Yuncheng Wang, Yuntian Zheng, Hai Wen, Jinhua Wang, Zuohua Huang","doi":"10.1016/j.combustflame.2025.114527","DOIUrl":"10.1016/j.combustflame.2025.114527","url":null,"abstract":"<div><div>Swirling bluff-body boundary layer flashback is a critical issue in lean-premixed gas turbine combustors but such flashback processes and the underlying mechanisms have not been well clarified in previous works especially considering different swirl intensities. In this work, effects of swirl intensity on the bluff-body boundary layer flashback of lean-premixed CH<sub>4</sub>/air flames were investigated via large eddy simulation (LES) and flamelet-generated manifold (FGM) methods. The numerical results were validated against the flow velocity, flashback speed and flashback mode which were experimentally measured with particle image velocimetry (PIV) and high-speed camera. It is shown that with higher swirl number (<em>SN</em>), the flashback is led by a large-scale flame tongue propagating upstream in the co-swirl direction (Mode I). With lower <em>SN</em>, the counter-swirl flashback is sustainable and dominant to proceed the flashback which is featured with smaller flame bulges propagating upstream against the swirl flow (Mode II). It is found that with lower <em>SN</em>, flashback starts with Mode I but can be transformed to be Mode II and turns back to Mode I again. The reason is revealed to be associated with the different axial and azimuthal components of the swirling velocity, and different flow deflection regions and low-momentum streaks formed upstream the flame tongue, when with different swirl intensity. Meanwhile, the boundary layer flashback with a low <em>SN</em> can be viewed as a non-swirling flashback in channel flows since the flame-induced adverse pressure gradient is examined to cause the velocity deflection during flashback whereas the rotational inertia forces are negligible. In contrast, flashback with a high swirl intensity is dominated by combined effects of the adverse pressure gradient and rotational inertia forces, which can be regarded as non-swirling channel flashback imposed with wall-normal body forces. The results are significant to further deepen understandings of the swirling bluff-body boundary layer flashback and help to improve its theoretical prediction models.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"282 ","pages":"Article 114527"},"PeriodicalIF":6.2,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263353","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}
Combustion and FlamePub Date : 2025-10-07DOI: 10.1016/j.combustflame.2025.114512
Shimon Pisnoy, Steven H. Frankel, Leonid Tartakovsky
{"title":"Large eddy simulation of unsteady flame dynamics in a sidewall quenching configuration","authors":"Shimon Pisnoy, Steven H. Frankel, Leonid Tartakovsky","doi":"10.1016/j.combustflame.2025.114512","DOIUrl":"10.1016/j.combustflame.2025.114512","url":null,"abstract":"<div><div>Flame–wall interaction (FWI) strongly affects wall heat transfer, near-wall flame extinction, and pollutant formation in combustion systems, with direct consequences for efficiency and emissions. Predicting and controlling these processes requires a mechanistic understanding of the coupled dynamics between wall-bounded flames and surrounding flow structures, yet this coupling remains insufficiently resolved under unsteady conditions. Using wall-resolved large-eddy simulation (LES) with detailed chemistry, this study identifies a recurrent amplification-transfer-dissipation cycle in turbulent sidewall quenching (SWQ) flames: upstream curvature perturbations, associated with unsteady flow features, accelerate the flame front and propagate toward the wall alongside a weak, co-rotating vortex. Near the wall, curvature growth is constrained and the front deforms into a hook-like shape. Perturbation energy transfers to a counter-rotating vortex, which dissipates it by compressing the flame, driving near-wall recirculation, steepening thermal and species gradients, and promoting localized quenching. Linking this cycle to flame stretch, coherent vortex dynamics, and thermochemical transitions, the work integrates geometric, flow, and chemical perspectives to advance modeling of near-wall extinction in turbulent combustion.</div><div><strong>Novelty and significance statement</strong></div><div>This study provides the first simulation-based characterization of the repeating amplify-transfer-dissipate cycle of curvature perturbations in turbulent sidewall quenching flames, governed by curvature- and strain-induced stretch under wall confinement. By linking this evolution to vortex dynamics and thermochemical transitions, it unifies geometric, flow, and chemical perspectives for improved near-wall extinction modeling.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"282 ","pages":"Article 114512"},"PeriodicalIF":6.2,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263475","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}
Combustion and FlamePub Date : 2025-10-07DOI: 10.1016/j.combustflame.2025.114514
Haodong Chen , Zhongkai Liu , Zhaoying Li , Ruzheng Zhang , Jiuzhong Yang , Nils Hansen , Bin Yang
{"title":"Kinetic investigation of CO2 reforming of dimethyl ether in a nanosecond pulsed discharge","authors":"Haodong Chen , Zhongkai Liu , Zhaoying Li , Ruzheng Zhang , Jiuzhong Yang , Nils Hansen , Bin Yang","doi":"10.1016/j.combustflame.2025.114514","DOIUrl":"10.1016/j.combustflame.2025.114514","url":null,"abstract":"<div><div>The chemical kinetics of plasma-assisted CO<sub>2</sub> reforming of dimethyl ether (DME) was investigated through combined experimental and numerical approaches. Experiments were conducted in a flow reactor (DME/CO<sub>2</sub>/Ar, 340 K, 30 Torr) with a nanosecond repetitively pulsed dielectric barrier discharge (DBD). Synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) was utilized to enable comprehensive species identification and quantification. Nine ions were detected: CH<sub>3</sub><sup>+</sup>, O<sup>+</sup>, Ar<sup>2+</sup>, CO<sup>+</sup>, CHO<sup>+</sup>, Ar<sup>+</sup>, CO<sub>2</sub><sup>+</sup>, CH<sub>3</sub>OCH<sub>2</sub><sup>+</sup>, and CH<sub>3</sub>OCH<sub>3</sub><sup>+</sup>. Key neutral intermediates and products identified based on the mass spectra and photoionization efficiency (PIE) spectra included methane (CH<sub>4</sub>), water (H<sub>2</sub>O), acetylene (C<sub>2</sub>H<sub>2</sub>), carbon dioxide (CO), ethylene (C<sub>2</sub>H<sub>4</sub>), formaldehyde (CH<sub>2</sub>O), ethane (C<sub>2</sub>H<sub>6</sub>), methanol (CH<sub>3</sub>OH), oxygen (O<sub>2</sub>), ketene (CH<sub>2</sub>CO), methyl hydroperoxide (CH<sub>3</sub>O<sub>2</sub>H), ethyl methyl ether (CH<sub>3</sub>OC<sub>2</sub>H<sub>5</sub>), methyl formate (CH<sub>3</sub>OCHO), and dimethoxymethane (CH<sub>3</sub>OCH<sub>2</sub>OCH<sub>3</sub>). Mole fraction profiles were measured as a function of inlet CO<sub>2</sub> concentration (3 % to 18 %, n<sub>DME</sub> = 3 %). The consumption of DME and formation of CH<sub>3</sub>OCHO were promoted with the addition of CO<sub>2</sub>, and the mole fractions of some products such as H<sub>2</sub>O, CO, CH<sub>3</sub>OH, and CH<sub>3</sub>OCH<sub>2</sub>OCH<sub>3</sub> exhibited a rise-and-fall pattern, while other species showed a monotonic decrease. A kinetic mechanism integrating plasma and combustion reactions was developed and validated against the experimental data, showing good predictive capability. Rate of production (ROP) analysis identified three primary DME consumption pathways: H-atom abstraction by O/H/OH radicals, dissociation induced by plasma-activated species such as electrons, Ar<sup>+</sup>, and Ar*, and protonation by ions. H-atom abstraction pathways were enhanced, while the dissociation channels were suppressed with increasing CO<sub>2</sub>. Under the conditions investigated, more than 60 % of the CO<sub>2</sub> consumption can be attributed to the electron/Ar* induced dissociation, forming CO and O, and the O radicals can promote DME low-temperature oxidation reactions.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"282 ","pages":"Article 114514"},"PeriodicalIF":6.2,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263354","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}