Combustion and Flame最新文献

{"title":"The influence of MILD-to-flame transition on stabilization, reactive structures, and emissions of NH3/H2 mixtures in a semi-industrial furnace","authors":"Ebrahim Rahmani ,&nbsp;Natalia Cid ,&nbsp;M․Mustafa Kamal ,&nbsp;Axel Coussement ,&nbsp;Alessandro Parente ,&nbsp;Marco Lubrano Lavadera","doi":"10.1016/j.combustflame.2025.114687","DOIUrl":"10.1016/j.combustflame.2025.114687","url":null,"abstract":"<div><div>Ammonia (NH₃) is a promising carbon-free fuel for decarbonizing energy systems, but its use in practical combustion systems is hindered by low flame stability and NOₓ emissions. Burning NH₃ with hydrogen (H₂) has been proposed to improve stability in conventional combustion systems; however, NOₓ emissions may persist or worsen. Moderate or Intense Low-Oxygen Dilution (MILD) combustion offers a pathway to suppress NOₓ through distributed reaction zones and reduced peak temperatures. The aim of this study is to stabilize pure NH₃ and characterize it with the H₂ addition in a semi-industrial reverse-flow furnace under MILD conditions. The experiments demonstrated the stabilization of pure NH₃ under MILD conditions without reactive enhancers, resulting in negligible NOₓ emissions but significant NH₃ slip. The impact of H₂ addition was assessed by analyzing how the transition from MILD to flame influences emissions. A transition from MILD to a lifted flame occurred at ∼14 % H₂, marked by a sharp rise in NOₓ and a steep decline in NH₃ slip. An optimal trade-off was observed at 12 % H₂, where NH₃ slip decreased from 2626 to 1336 ppm, accompanied by only a 12 ppm increase in NO, while maintaining MILD conditions. Decreasing the furnace temperature extended MILD combustion to 20 % H₂, but compared to the 12 % H₂, it caused higher NH₃ slip and only a slight reduction in NO, highlighting a trade-off between temperature control and NH₃ decomposition. The experimental findings were analyzed from a chemical kinetic viewpoint using a chemical reactor network approach. The results showed that NO reduction at H₂≤20 % was dominated by thermal DeNO_x, while NO formation at H₂≤80 % primarily originated from fuel-bound nitrogen. These findings advance the understanding of NH₃-H₂ MILD combustion at realistic scales and provide insight into the design of low-emission ammonia-based systems.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"284 ","pages":"Article 114687"},"PeriodicalIF":6.2,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145691366","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":"Study on the explosion characteristics and mechanism of hydrogen at different concentrations inhibited by inert gases","authors":"Xiaotong Wang ,&nbsp;Baisheng Nie ,&nbsp;Leilei Li ,&nbsp;Weili Wang ,&nbsp;Cheng Zhou","doi":"10.1016/j.combustflame.2025.114658","DOIUrl":"10.1016/j.combustflame.2025.114658","url":null,"abstract":"<div><div>Hydrogen, as an important renewable energy source, is widely used but also has the potential safety hazard of explosion. Therefore, it is of great significance to study the explosion characteristics of hydrogen and the suppression mechanisms. This paper combines experimental research and numerical simulation based on the visual explosion pipeline experimental system to study the macro-inhibition laws and micro-inhibition mechanisms of hydrogen explosions by single and composite inert gases. The results showed that as the volume fraction of inert gas increased, macro explosion parameters such as explosion pressure, pressure rise rate, and detonation index all exhibited a decreasing trend. Furthermore, the critical volume fraction ranges for single and composite inert gases to completely suppress hydrogen explosions at different concentrations were determined, with the inhibitory effects of inert gases following the order CO₂ &gt; CO₂ + N₂ &gt; N₂. According to Chemkin simulations, the laminar flame speed of hydrogen combustion after the addition of inert gas is positively correlated with the adiabatic temperature and thermal diffusivity, and both decrease with increasing inert gas content, consistent with the change in explosion pressure. In addition, the addition of inert gases can reduce the concentration of H₂ and O₂, thereby lowering the collision probability of free radicals. Since CO₂ can also undergo chemical reactions (R32: CO + OH = H + CO₂), it consumes H free radicals and slows down the hydrogen explosion chain reaction, making CO₂ the most effective inhibitor.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"284 ","pages":"Article 114658"},"PeriodicalIF":6.2,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145691270","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":"Investigating dimensional effects for improved modeling of opposed-flow solid fuel combustion","authors":"Ryan D. DeBoskey ,&nbsp;Clayton M. Geipel ,&nbsp;Brian T. Bojko ,&nbsp;Brian T. Fisher ,&nbsp;David A. Kessler ,&nbsp;Ryan F. Johnson ,&nbsp;Venkateswaran Narayanaswamy","doi":"10.1016/j.combustflame.2025.114670","DOIUrl":"10.1016/j.combustflame.2025.114670","url":null,"abstract":"<div><div>Simplified experimental configurations, such as the opposed-flow burner (OFB), are well-suited for fundamental investigation of the coupled solid fuel decomposition and combustion processes that occur in solid fuel ramjets and hybrid rockets. However, the high oxidizer flow rates (necessary for sustaining combustion) and low fuel blowing velocity from pyrolysis that are typically observed in the OFB introduce many dimensional effects that remain largely underexamined. This study investigates a series of parametric two-dimensional axisymmetric large-eddy simulations of hydroxyl-terminated polybutadiene (HTPB) combustion in an OFB. Numerical simulations are performed at 50% and 100% oxygen composition with increasing mass flux to compare with experimental measurements. Non-uniformity at the oxidizer nozzle and fuel surface, owing to large oxidizer flow rates and proximal separation distances, is observed. The inflow velocity spreading rates are extracted and used to calibrate an improved quasi one-dimensional counterflow flame model. The resulting quasi one-dimensional model significantly improves the prediction of flame standoff (35%) and regression rate (275%) within the OFB compared to the baseline model without spread rate consideration. Results demonstrate prediction of flame structure is considerably more sensitive to spread rate than chemical kinetics mechanism or solid fuel thermophysical modeling.</div><div><strong>Novelty and significance statement</strong></div><div>The inflow boundary spread rates were quantified for the first time in a solid fuel opposed-flow burner using high-fidelity predictive simulations. Correcting for this phenomenon was shown to significantly improve quasi one-dimensional model accuracy with experiment, a fundamental tool for determining useful chemical kinetics and pyrolysis modeling in heterogeneous combustion. The present results (1) underscore the importance of including nonuniform inflow conditions for the accurate modeling of solid fuel diffusion flames and (2) outline a methodology for quantifying the near wall physics at the solid fuel surface.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"284 ","pages":"Article 114670"},"PeriodicalIF":6.2,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145691269","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":"Linear analysis of thermo-diffusive instability from edge flames to fully-premixed laminar flames with a wide range of Damköhler number and Lewis number greater than unity","authors":"David Bhatt,&nbsp;Daniel Rodríguez","doi":"10.1016/j.combustflame.2025.114694","DOIUrl":"10.1016/j.combustflame.2025.114694","url":null,"abstract":"<div><div>A model problem for thermo-diffusive instabilities on planar laminar flames is considered, which studies flames stabilized in the proximity of a cold burner in a co-flow mixing layer between fuel and oxidizer streams. It accounts for the driving mechanisms for the onset of thermo-diffusive instability, but assumes constant density and neglects flow or pressure gradients. A premixedness parameter characterizes the transverse gradient of the mixture fraction at the upstream boundary. By varying the premixedness parameter from zero to unity, different flame structures are recovered covering the complete spectrum from non-premixed edge flames to fully-premixed planar flames, through partially-premixed triple flames. A modal linear stability analysis is presented. The equations governing small-amplitude flame fluctuations are recast as an eigenvalue problem, in which the eigenfunctions describe two-dimensional flow field variables with arbitrary spatial dependence, and the eigenvalues describe the oscillation frequency and temporal growth rate. For all partially-premixed flames, a pair of complex eigenvalues are found, corresponding to upstream–downstream pulsations of the flame leading edge. These eigenmodes are unstable for a bounded region in the Premixedness-Damköhler space. Fully-premixed flames present multiple pairs of unstable eigenmodes; the most unstable pair corresponds to an upstream–downstream oscillation of the flame without distortion along the transverse direction, while the subsequent ones describe wavy deformations of the flame structure consistent with the formation of cellular patterns. The predictions of the linear stability analysis compare well with results from nonlinear simulations.</div><div>Novelty and significance statement</div><div>A novel methodology is presented for the instability analysis of laminar flames that considers linear eigenmodes with arbitrary dependence on two spatial directions. The computationally-inexpensive approach allows to perform vast parametric studies of the influence of the physical parameters, thus providing new physical insights. Here, it is applied to a model problem for thermo-diffusive instability, that allows studying the complete range of flames possible in a co-flow configuration in a unified set up. A wide range of Damköhler numbers a premixedness parameters are analyzed and the instability maps are reported, which is a novelty in the literature. The methodology proposed can be directly applied to other 2D configurations and can incorporate more complex phenomena like the coupling between the thermodiffusive instability and flow and pressure gradients, and differential diffusivity.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"284 ","pages":"Article 114694"},"PeriodicalIF":6.2,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145691268","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":"A novel combinatorial approach to evaluate the ignition and combustion performance of aluminum powders alloyed with other elements","authors":"John Fite ,&nbsp;Michael Flickinger ,&nbsp;John Carbo ,&nbsp;Anthony Megalla ,&nbsp;Isaiah Queen ,&nbsp;Michael Kruppa ,&nbsp;Preetom Borah ,&nbsp;Megan Bokhoor ,&nbsp;Milad Alemohammad ,&nbsp;Colin Goodman ,&nbsp;Mark Foster ,&nbsp;John Slotwinski ,&nbsp;Timothy P. Weihs","doi":"10.1016/j.combustflame.2025.114640","DOIUrl":"10.1016/j.combustflame.2025.114640","url":null,"abstract":"<div><div>Promptly neutralizing stockpiles of bio- and chem-agents without dispersing them depends in part on tailoring the ignition and combustion performance of reactive metal powders through alloying. Careful selection of chemistry can enhance heat release and nano oxide production. However, the prodigious alloy design space necessitates high-throughput experimental techniques for systematic alloy screening. This work demonstrates a novel combinatorial approach that uses physical vapor deposition to fabricate Al-Zr and (Al 8 at% Mg)-Zr powders with well controlled volumes and microstructures and compositions ranging from zero to 23 at% Zr. The microscale powders ignite in air above 14 at% Zr, and their ignition temperatures decrease linearly as more Zr is added. Oxidation and combustion vary nonlinearly with Zr content, showing dramatic increases in the degree of oxidation and the number of hot particles above 19–20 at% Zr. The addition of 8 at% Mg is found to aid both ignition and combustion.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"284 ","pages":"Article 114640"},"PeriodicalIF":6.2,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145691271","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":"Synergistic suppression of magnesium dust explosions by montmorillonite/ammonium polyphosphate composites: Experimental and kinetic modeling insights","authors":"Dongyang Qiu ,&nbsp;Mohammad Zaid Kamil ,&nbsp;Mohammad Alauddin ,&nbsp;Lijuan Liu ,&nbsp;Xianfeng Chen ,&nbsp;Chuyuan Huang ,&nbsp;Paul Amyotte","doi":"10.1016/j.combustflame.2025.114667","DOIUrl":"10.1016/j.combustflame.2025.114667","url":null,"abstract":"<div><div>Magnesium (Mg) dust in metal processing and energy settings exhibits high explosion sensitivity and strong destructiveness, readily triggering cascading accidents. To precisely control this risk, this study mechanochemically prepared montmorillonite (MMT) and ammonium polyphosphate (APP) composite inhibitors, established a vertical combustion duct platform, evaluated its suppression efficacy for Mg dust explosions, and combined residue characterization, thermal analysis, and Chemkin simulations to elucidate the synergistic suppression mechanism. The MMT/APP composite outperformed single components; at an inerting ratio (α) = 1.25, the 1:1 formulation fragmented the flame, prevented the formation of a continuous front, and self-extinguished at mid-duct. Relative to pure Mg dust, the maximum flame velocity (<em>V</em>_max) decreased by 91.5%; the peak flame front pressure (<em>P</em>_max) and the maximum rate of pressure rise ((<em>dP</em>/<em>dt</em>)_max) were reduced by 97.6% and 98.0%, respectively; and the peak temperature (<em>T</em>_p) fell to 236°C. Mechanistically, MMT provides endothermy alongside heat and mass transfer shielding. At elevated temperature, MMT forms refractory SiO₂ and Al₂O₃ phases and lamellae that suppress O₂ diffusion and interparticle heat conduction. Gas phase reaction kinetics simulations indicate that APP decomposes endothermically to generate nitrogen and phosphorus-containing intermediates that markedly deplete the O radical, manifested as rapid chain termination along the nitrogen pathway and sustained suppression along the phosphorus pathway. This study provides quantitative guidance for the formulation of efficient Mg dust inhibitors and supports improvements in the inherent safety of Mg processing.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"284 ","pages":"Article 114667"},"PeriodicalIF":6.2,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145691307","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":"Dielectric interface modification enables low-power microwave ignition of aluminum particles: Mechanisms and combustion performance evaluation","authors":"Xiaoyuan Chen ,&nbsp;Xi Chen ,&nbsp;Bin Zhang ,&nbsp;Tuan Zhao ,&nbsp;Jia Zhao ,&nbsp;Kangzhen Xu ,&nbsp;Suhang Chen","doi":"10.1016/j.combustflame.2025.114657","DOIUrl":"10.1016/j.combustflame.2025.114657","url":null,"abstract":"<div><div>Microwave ignition technology holds transformative potential in multi-point simultaneous uniform ignition for propulsion systems and energy conversion, attributable to its non-intrusive energy delivery and rapid response characteristics, yet it faces challenges in igniting metallic fuels like aluminum (Al) particles inert to microwaves. To address this critical problem of microwave energy coupling inefficiency in Al, interfacial layers of PF (C₈H₁₂ClNO₂ and CF₃(CF₂)₇CH₂CH₂SH) and APTES (C₉H₂₃NO₃Si) were constructed to introduce chemical bonding and electrostatic adsorption on the Al surface, followed by inducing CUFO (CuFe₂O₄) dielectric interface anchoring and forming Al@PF@CUFO and Al@APTES@CUFO. This construction of core/shell not only shortens the mass and heat transfer distance but also enhances the interfacial polarization, leading to a strong response to microwaves. Microwave ignition analysis indicates that Al@APTES@CUFO (23.41 ms) exhibits a shorter ignition delay time compared to Al@PF@CUFO (29.51 ms), which can be attributed to the superior bridging capability and rapid decomposition of APTES. APTES not only shortens mass and heat transfer pathways but also facilitates rapid microwave energy absorption by Al/CUFO under microwave irradiation, generating localized hotspots and accelerating the ignition reaction kinetics. Furthermore, Al@PF@CUFO reveals a 327% increase in combustion rate compared to Al@APTES@CUFO, attributed to the fluorination reaction induced by PF decomposition and carbon catalysis derived from the decomposition of PDA. These findings establish dielectric interface engineering as a paradigm-shifting approach to overcome microwave ignition barriers in metallic fuels, with implications for next-generation microwave-controlled solid propellants, pyrotechnics, explosives, etc.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"284 ","pages":"Article 114657"},"PeriodicalIF":6.2,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145691304","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":"On the use of a sensitivity-enhanced algorithm to quantify sooting dynamics in droplet combustion of highly sooty fuels","authors":"Minghui Xu ,&nbsp;Xi Liu ,&nbsp;Michael C. Hicks ,&nbsp;C. Thomas Avedisian ,&nbsp;Yuhao Xu","doi":"10.1016/j.combustflame.2025.114668","DOIUrl":"10.1016/j.combustflame.2025.114668","url":null,"abstract":"<div><div>This paper describes a sensitivity-based algorithm for extracting the soot volume fraction (SVF, <em>f_v</em>) from digital video images of organic liquid droplets burning under conditions that promote spherically symmetric gas transport. The algorithm was applied for the first time to digital video images of <em>n</em>-propylbenzene (<em>n</em>P) droplets with initial diameters (<em>D₀</em>) ranging from 2.1 mm to 5.8 mm. The SVF was obtained by measuring the intensity of light along rays-of-interest (ROIs) through a droplet’s center on the images. A “greedy algorithm” was employed to calculate the dynamic Coefficient of Variation to optimize the number of ROIs and thus enhance the repeatability and accuracy of SVF data. These data analysis efforts revealed many new physical insights into the sooting dynamics of a heavily sooty fuel, <em>n</em>P. The results showed that <em>f_v</em> increased with time for a given <em>D₀</em>, reached a maximum (<em>f_v,</em> _max), then decreased. Also, <em>f_v,</em> _max coincided with the measured soot shell location. The actual mass of soot formed as a function of time followed this same trend, increasing first because of fuel pyrolysis and then decreasing because of oxidation. While the peak value of <em>f_v,</em> _max over the entire duration of a burn (<em>f *_v,</em> _max) decreased with increasing <em>D₀</em>, the maximum mass of soot (<em>m_s,</em> _max) itself increased linearly with <em>D₀²</em>.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"284 ","pages":"Article 114668"},"PeriodicalIF":6.2,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621517","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":"Ignition and combustion characteristics of cyclopentanone and cyclopentanone/gasoline blends: An experimental and modeling study","authors":"Jiaqi Zhang ,&nbsp;Florian vom Lehn ,&nbsp;Sascha Jacobs ,&nbsp;Raik Hesse ,&nbsp;Joachim Beeckmann ,&nbsp;Xudong Wu ,&nbsp;Karl Alexander Heufer ,&nbsp;Heinz Pitsch ,&nbsp;Liming Cai","doi":"10.1016/j.combustflame.2025.114647","DOIUrl":"10.1016/j.combustflame.2025.114647","url":null,"abstract":"<div><div>This paper presents an experimental and numerical study on the ignition and combustion characteristics of the novel biofuel cyclopentanone and its blends with RON95E10 gasoline fuel at a volumetric blending ratio of 50%. The characterized research grade gasoline fuel RON95E10 is modeled by a dedicated surrogate defined in a previous study. Ignition delay times of cyclopentanone and the blends were measured in a shock tube and a rapid compression machine, while their laminar burning velocities were investigated in a combustion vessel. All measurements cover a large variety of initial conditions and are of value for kinetic model development and validation. A detailed kinetic model is derived to describe the oxidation of cyclopentanone and its blends with gasoline at both low and high temperatures, which shows good agreement with the present datasets. In order to understand the underlying oxidation chemistry of cyclopentanone, reaction pathway and sensitivity analyses are performed by using the proposed kinetic model. The favorable H-abstraction site of cyclopentanone is at the <span><math><mi>β</mi></math></span> carbon, owing to the presence of the carbonyl group. The dominance of chain-terminating HO₂-elimination reflects the weak low-temperature reactivity of cyclopentanone as a fuel. An additional key focus of this study is to explore the blending effect of cyclopentanone on gasoline. Results demonstrate that both chemical kinetic and physical dilution impacts are responsible for the ignition suppression at low to intermediate temperatures when adding cyclopentanone. The kinetic effect is mainly attributed to the fact that cyclopentanone scavenges OH radicals produced by gasoline surrogates. At high temperatures, the ignition delay times of cyclopentanone/gasoline blends are mainly affected by the chemistry of cyclopentanone.</div><div><strong>Novelty and significance statement</strong></div><div>This work is of particular significance due to the potential of cyclopentanone as a novel biofuel and it is a pioneering study focusing on the combustion of its blends with conventional gasoline fuels. The ignition delay times and laminar burning velocities of cyclopentanone and cyclopentanone/gasoline blends at specific experimental conditions are reported for the first time. A comprehensive kinetic model is developed for both low- and high-temperature oxidation of cyclopentanone/gasoline blends with high predictive accuracy, which is missing in the literature. This work reveals the strong interaction between gasoline and cyclopentanone in terms of auto-ignition at low temperatures and provides further evidence on the OH-scavenging effect. Both chemical kinetic and physical dilution impacts are quantified. The results of this work offer new insights into the ignition and combustion behaviors of cyclopentanone/gasoline blends, which is of importance for future engine optimization.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"284 ","pages":"Article 114647"},"PeriodicalIF":6.2,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621520","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":"Differential diffusion effects in a lean-premixed bluff-body stabilized hydrogen flame","authors":"Weiyue Liu,&nbsp;W.P. Jones","doi":"10.1016/j.combustflame.2025.114682","DOIUrl":"10.1016/j.combustflame.2025.114682","url":null,"abstract":"&lt;div&gt;&lt;div&gt;This paper describes the results of compressible large eddy simulations, with the Stochastic Fields method, of a lean-premixed bluff-body hydrogen flame. Both the LES isothermal and the reacting fields show good agreement with the measurements, revealing the capability of the Stochastic Fields method in bluff-body hydrogen flames. For the reacting field, two diffusive transport models, the constant Schmidt/Prandtl number approximation and mixture-averaged diffusion transport are implemented independently to isolate the effects of differential diffusion on species concentrations and temperature. The mixture-averaged diffusion transport model performs better than the constant Schmidt/Prandtl in terms of mean flame shape. Mixture-averaged diffusion results in local enrichment of the flame root, higher heat release rates, temperatures, fuel consumption rates and more diffused species profiles. High-temperature burnt gas in the recirculation zone elevates the significance of molecular diffusion, related to possible re-laminarization. The results reveal the importance of the inclusion of accurate molecular diffusive transport for hydrogen flames in lean-premixed bluff-body stabilized flames. DMD analysis suggests that both diffusion methods can recover the significant dynamic behaviour of the reacting flow system. Some physical-space differences between the two approaches are also shown in terms of their DMD modes.&lt;/div&gt;&lt;div&gt;&lt;strong&gt;Novelty and Significance Statement&lt;/strong&gt;&lt;/div&gt;&lt;div&gt;The present work describes an LES study of the effect of differential diffusion on the hydrogen lean-premixed flames. The effect is isolated by comparing LES results obtained with two molecular diffusive transport models; the constant Schmidt/Prandtl number approximation and the mixture-averaged diffusion transport model applied to a bluff-body stabilized hydrogen flame. The solutions from the two diffusion transport methods are compared and analysed regarding flow field and flame characteristics. Dynamic mode decomposition is applied for further analysis. The results highlight the importance of including the differential diffusion effects in lean bluff-body stabilized hydrogen flames. The result is likely to helpful in the simulation of a wide range of hydrogen flame applications.&lt;/div&gt;&lt;div&gt;The present work provides an example of hydrogen flame compressible LES with relatively manageable computational costs (3.5M mesh cells) and a multi-regime-robust flame model, i.e., the Stochastic Fields method. The method avoids any assumptions regarding flame regime burning and burning mode selection or parameter tuning. The method also allows the incorporation an ‘accurate’ diffusive transport model, e.g., mixture-averaged, in a relatively straightforward manner. This may significantly help the study and simulation of hydrogen flames.&lt;/div&gt;&lt;div&gt;The present work systematically analyses the physical and chemical processes that occurred in the lean-premixed hydrogen flame a","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"284 ","pages":"Article 114682"},"PeriodicalIF":6.2,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621398","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}