Applications in Energy and Combustion Science最新文献

{"title":"Progress in fundamental combustion characteristics, surrogate formulation, and kinetic modeling of sustainable aviation fuels","authors":"Yilun Liang ,&nbsp;Fanggang Zhang ,&nbsp;Juan Wang","doi":"10.1016/j.jaecs.2025.100417","DOIUrl":"10.1016/j.jaecs.2025.100417","url":null,"abstract":"<div><div>The adoption of sustainable aviation fuels (SAFs) is essential for achieving the carbon reduction targets. To enable numerical simulations involving SAFs, the development of its chemical kinetic mechanism is an indispensable task. During this process, measuring the fundamental properties of SAFs, formulating surrogate mixtures, and selecting appropriate kinetic mechanisms for surrogate components are crucial steps. This paper presents a comprehensive review of combustion kinetics research related to SAFs. It summarizes and compares the properties of various types of SAFs and their combustion characteristics, including ignition delay times, laminar flame speeds and species mole fractions. Additionally, the influence of fuel component structures on combustion behavior is analyzed. The paper also reviews studies on surrogate formulation strategies for SAFs and evaluates the associated methodologies. Based on these strategies, suitable surrogate components and their corresponding kinetic mechanisms are recommended. It is hoped that this work will contribute to a deeper understanding of SAF kinetic modeling for researchers and provide valuable guidance for future studies in this field.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"24 ","pages":"Article 100417"},"PeriodicalIF":5.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fire scale modeling and effects of buoyant flow on laminar upward flame spread","authors":"Nicharee Thinnakornsutibutr ,&nbsp;Arianna Su ,&nbsp;Ankit Sharma ,&nbsp;Ya-Ting Liao","doi":"10.1016/j.jaecs.2025.100411","DOIUrl":"10.1016/j.jaecs.2025.100411","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Over the last few decades, efforts to improve fire safety have emphasized understanding material flammability through small-scale laboratory testing due to safety and cost constraints. However, extending these findings to real-world fire scenarios is challenging, as buoyancy-driven flows—critical to fire behaviors—vary significantly with scales. The objective of this numerical study is to understand the effects of buoyant flow on fire dynamics, specifically in the context of upward flame spread over vertically oriented solid fuels. To approach the problem incrementally, simulations are first performed for inert thermal plume (no combustion), followed by simulations of laminar upward flame spread over a thin solid material. The results show that the boundary layer thicknesses and flame standoff distance increase when gravity and pressure decrease, and scale with &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;0.5&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;0.25&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. The buoyant flow magnitude increases with gravity but remains the same when pressure is varied (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;U&lt;/mi&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;/msub&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mo&gt;∼&lt;/mo&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/msup&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0.5&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;). The results of upward flame spread simulations further show that reaction rate, flame temperature, and flame spread rate have positive correlations with both pressure and gravity. Interestingly, while the incident radiative heat flux on the solid surface (&lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mover&gt;&lt;mi&gt;q&lt;/mi&gt;&lt;mo&gt;˙&lt;/mo&gt;&lt;/mover&gt;&lt;mrow&gt;&lt;mi&gt;f&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;″&lt;/mo&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt;) increases with ambient pressure, it is insensitive to gravity. Nevertheless, &lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mover&gt;&lt;mi&gt;q&lt;/mi&gt;&lt;mo&gt;˙&lt;/mo&gt;&lt;/mover&gt;&lt;mrow&gt;&lt;mi&gt;f&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;″&lt;/mo&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt; has a minor effect on the net heat flux, owing to the dominant contribution of convective heat input. Comparing cases of a constant &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msup&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, distributions of convective and net heat fluxes, solid surface temperatures, and solid mass loss rates are generally similar, resulting in similar overall flame behaviors. However, thermal inertia and flame radiation loss are both lower in a reduced pressure environment. This leads to higher flame temperature and higher convective heat input in a small region near the flame base, weakening the effects of pressure on flame spread. Because of this, when applying &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msup&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; pressure modeling, the flame spread rate is higher in reduced pressure than in reduced gravity. The results further show that &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;1.8&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;mi&gt;g&lt;/","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"24 ","pages":"Article 100411"},"PeriodicalIF":5.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145323710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Oxygenated polycyclic aromatic hydrocarbons as key coke precursors in coke formation during zeolite-catalyzed furfural pyrolysis","authors":"Zhongyue Zhou ,&nbsp;Haoran Liu ,&nbsp;Xinghua Liu ,&nbsp;Chih-Hao Chin","doi":"10.1016/j.jaecs.2025.100389","DOIUrl":"10.1016/j.jaecs.2025.100389","url":null,"abstract":"<div><div>Coke deposition and catalyst deactivation represent significant challenges in catalytic research, yet the mechanisms underlying their formation remain inadequately understood. Herein, we employed the HZSM-5 catalyzed conversion of furfural as a model reaction and, using a newly developed online high-resolution mass spectrometry (HRMS) technique, directly detected a broad spectrum of oxygenated polycyclic aromatic hydrocarbons (OPAHs) under reaction conditions. Solid-state NMR further revealed the functional group architectures of OPAH side chains in condensed-phase coke, while density functional theory (DFT) calculations elucidated plausible formation and transformation pathways. These complementary approaches establish that highly active OPAHs serve as crucial intermediates in the coke deposition process. We propose a novel mechanism in which light OPAHs, orginating from small-molecule products, undergo rapid polymerization at the active sites to yield larger polycyclic aromatic hydrocarbons, traditionally classified as coke. This newly identified mechanism highlights the unexpectedly rapid coking during the catalytic pyrolysis of biomass, and underscores the significant role of OPAHs in catalyst deactivation. By providing molecular-level insights into coke growth, this study lays a foundation for strategies to suppress coke formation, thereby improving the efficiency and sustainability of catalytic conversion technologies for biomass utilization.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"24 ","pages":"Article 100389"},"PeriodicalIF":5.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145105681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A digital soot foil method for the analysis of cellular structures in detonation waves","authors":"Robyn Cideme,&nbsp;Liliana Berson,&nbsp;Rachel Hytovick,&nbsp;Kareem Ahmed","doi":"10.1016/j.jaecs.2025.100372","DOIUrl":"10.1016/j.jaecs.2025.100372","url":null,"abstract":"<div><div>The advent of detonation-based propulsion systems represents an opportunity for more sustainable combustion processes. Though highly unstable, some detonations carry information on their constituting waves and instabilities through a cellular structure. Such detonations observe patterns with diamond-shaped cells, delimited by Mach reflections at their vertices. These are formed by the collision of triple points, historically described as a 3-shock structure between an incident shock, Mach stem and transverse wave. The present work investigates the dynamics of detonation waves at a sub-cellular level in hydrogen–oxygen–nitrogen mixtures. The diluent content is varied experimentally while the equivalence ratio is maintained to unity. Characteristic lengths scales such as the cell width and length are reported, along with local measurements of wave velocity through shadowgraph imaging. Due to the three dimensional nature of detonations, experiments are conducted in a thin channel to minimize gradients in the third dimension and favor a quasi 2D propagation of the detonation wave. The stochastic behavior of the phenomenon is reported using a statistical approach and leverages a new methodology for the simultaneous resolution of the velocity field and cellular structure. The results first show an exponential decrease in cell sizes with the dilution content through the decreased activation energy. Furthermore, the formation of Mach reflections is seen to be associated with sudden and sharp velocity gradients at high dilution, resulting in a more irregular distribution of the wave velocity. Ultimately, the digital soot foils provide new insights into cellular structures and the wave dynamics surrounding Mach reflections.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"24 ","pages":"Article 100372"},"PeriodicalIF":5.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145105678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study of coupling characteristics between flame dynamics and CO emissions using wavelength modulation spectroscopy","authors":"Weitian Wang ,&nbsp;Pengfei Fu ,&nbsp;Lingyun Hou ,&nbsp;Xing Chao ,&nbsp;Yao Mi ,&nbsp;Zhenhai Wang ,&nbsp;Rémy Mével ,&nbsp;Gaofeng Wang","doi":"10.1016/j.jaecs.2025.100386","DOIUrl":"10.1016/j.jaecs.2025.100386","url":null,"abstract":"<div><div>The coupled characteristics of flame dynamics and emissions in energy systems are critical for understanding combustion instability mechanisms and implementing effective emission control, necessitating high temporal-resolution optical diagnostic methods for dynamic, <em>in</em>-<em>situ</em> measurement of combustion products. This study experimentally investigates the coupling characteristics between flame dynamics and CO emissions in a centrally staged combustor using wavelength modulation spectroscopy (WMS). The developed WMS measurement strategy provides millisecond-resolution insights into the fluctuations of CO emissions, while simultaneous flame imaging was performed using high-speed OH* chemiluminescence. As the staging ratio increases, the flame in the central recirculation zone intensifies and interacts with the shear-layer flame, resulting in combustion instabilities. The dominant frequency of CO fluctuations at 267 Hz is coupled with both the acoustic pressure and flame intensity. The dynamic CO emissions are correlated to the overall flame intensity and axial convective motion by coherent flame modes analysis. Periodic heat release and localized flame quenching are identified as the primary sources of CO fluctuations. This work contributes to a deeper understanding of the coupling mechanisms between flame dynamics and emissions in centrally staged combustion systems, offering valuable guidance for the synergistic control of combustion instability and pollutant formation.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"24 ","pages":"Article 100386"},"PeriodicalIF":5.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145049499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anharmonic effect in the hydrogen atom abstraction reaction kinetics of amino radicals and methanol","authors":"Peng Guo ,&nbsp;Xuefei Xu","doi":"10.1016/j.jaecs.2025.100406","DOIUrl":"10.1016/j.jaecs.2025.100406","url":null,"abstract":"<div><div>The combustion of the ammonia/methanol blends has attracted much attention due to the potential to reduce carbon emissions. Some previous research had pointed out the importance of involving cross-reactions in the combustion simulation of the ammonia/methanol blends, especially the hydrogen abstraction reaction of amino (NH₂) radicals and methanol. Therefore, we carried out a detailed kinetics study of the reaction of NH₂ and methanol in a wide temperature range. The potential energy surface was calculated using the high-level W3X-L//M08-HX/MG3S method, and the specific-reaction-parameter (SRP) scaling factors of frequencies were calculated and used to correct the stronger high-frequency anharmonicity in the transition states than the reactants. The canonical variational transition state theory was used to calculate the rate constants over the temperature range of 200–2000 K, with multi-structural torsional anharmonicity correction and the small curvature tunneling approximation (MS-CVT/SCT). The results show that the stronger high-frequency anharmonicity of the transition states significantly affects the barrier height and thereby causes a deviation factor of 17.5 at 200 K and 1.8 at 2000 K in the prediction of the reaction rates on -OH site of CH₃OH and a deviation factor of 7.5 at 200 K and 1.2 at 2000 K in the branching ratios on -CH₃ site of CH₃OH in the reaction of CH₃OH and NH₂ radicals. In addition, the variational effect and the multi-structural torsional anharmonicity cannot be ignored in the reaction of CH₃OH and NH₂ radicals. These results can also provide references for evaluating the uncertainty in the reaction kinetics calculations of NH₂ radicals with other alcohol fuels.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"24 ","pages":"Article 100406"},"PeriodicalIF":5.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145266088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Flamelet LES of solid fuel/ammonia co-combustion with differential diffusion","authors":"Xu Wen ,&nbsp;Ali Shamooni ,&nbsp;Thorsten Zirwes ,&nbsp;Christian Hasse","doi":"10.1016/j.jaecs.2025.100387","DOIUrl":"10.1016/j.jaecs.2025.100387","url":null,"abstract":"<div><div>Differential diffusion is expected to be important in a pulverized coal/ammonia co-combustion system due to the co-existence of heavy species in volatiles and light species in the ammonia stream. In this work, the multi-stream flamelet model for piloted pulverized coal/ammonia co-combustion is further extended to incorporate differential diffusion in the framework of large-eddy simulation (LES). The flamelet solutions are obtained by solving the flamelet equations with differential diffusion, and tabulated as a function of four mixture fractions, reaction progress variable and total enthalpy. The governing equation for the total mixture fraction is derived based on element conservation, and the effects of differential diffusion are explicitly considered by an additional term, i.e., the differential diffusion term. The governing equations for the other manifold coordinates with differential diffusion are formulated in a similar way. The differential diffusion terms are closed by relating them to the manifold coordinates based on the 1D flamelet assumption. The suitability and performance of the proposed flamelet model with differential diffusion are evaluated by comparing with the detailed chemistry solutions for a laminar pulverized coal/ammonia counterflow flame and the flamelet model based on the unity Lewis number assumption through an <em>a priori</em> analysis. A fully-coupled flamelet/LES is applied to a laboratory-scale pulverized coal/ammonia CRIEPI burner, and the simulation results are compared with the available experimental data. The comparisons show that the flamelet model with differential diffusion can accurately predict the thermo-chemical quantities, and outperforms the flamelet model based on the unity Lewis number assumption, particularly for the prediction of temperature and NO<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span> species mass fractions.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"24 ","pages":"Article 100387"},"PeriodicalIF":5.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145105679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unleashing high-efficiency biohydrogen production from Arundo donax L. through interfacial charge transferring in hybrid catalytic systems by regulating metabolism","authors":"Mujeeb Alam ,&nbsp;Zheng Wang ,&nbsp;Zhiping Zhang ,&nbsp;Hina Ramzan ,&nbsp;Jiang Danping ,&nbsp;Faiqa Nadeem ,&nbsp;Siming You ,&nbsp;Quanguo Zhang","doi":"10.1016/j.jaecs.2025.100419","DOIUrl":"10.1016/j.jaecs.2025.100419","url":null,"abstract":"<div><div>This study examines photo-fermentative biohydrogen production (PFHP) from <em>Arundo donax</em> L. using binary (SiC/ZnO) and ternary (SiC/ZnO/SnO₂) co-catalyst systems. The maximum cumulative hydrogen production of 110 mL/g and hydrogen production rate of 39.74 mL/g·h⁻¹ at 24 h was achieved in ternary-C2 group of ternary system which was 73.23 % higher as compared to the CG (63.5 mL/g), also outperforms binary system (97.58 mL/g, 35.81mL/g·h⁻¹) by 12.73 % and 10.97 %. The binary system achieved a 48.67 % hydrogen content percentage, while the ternary system had 52.53 %, which is 14 % and 18.3 % higher than the control group. Multi-interface heterojunctions occur synergistically, which is the source of the increased activity. In addition to accelerating electron migration and inhibiting electron–hole recombination, this arrangement facilitates effective interfacial charge transfer. Together, these effects produce a favourable redox environment that improves bacterial metabolism and sustains a process of hydrogen production. Maximum light absorption and charge-separation efficiency may explain the ternary system's faster metabolism and microbial activity. Ternary system hydrogen production enhanced the charge transfer by reducing the oxidation–reduction potential (-408 mv) and lag phase reduced to 8.48 h from 14.71 h in binary system, a 53.73 % performance boost. Maximum Energy Conversion Efficiency of 8.1 % was achieved in experimental group ternary-C2 of ternary system which is 12 % and 52.83 % better than binary system (7.2 %) and control (5.3 %). The ternary system provides a better hydrogen production metabolite route and reduces VFA’s accumulation.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"24 ","pages":"Article 100419"},"PeriodicalIF":5.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145528778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A numerical investigation on the flow effect over the Nusselt number in single droplet combustion","authors":"Hippolyte Cléris ,&nbsp;Sébastien Tanguy ,&nbsp;Olivier Rouzaud ,&nbsp;Jean-Luc Estivalèzes ,&nbsp;Annafederica Urbano","doi":"10.1016/j.jaecs.2025.100400","DOIUrl":"10.1016/j.jaecs.2025.100400","url":null,"abstract":"<div><div>Numerical simulations of the combustion of isolated droplets, based on an interface capturing two-phase flow solver, are presented in this paper. The new numerical solver used is an extension of a classical evaporation solver based on a Level Set-Ghost Fluid Method to combustion applications. It is based on a variable density low Mach number solver for Navier–Stokes equations, and it accounts for complex thermo-physical variations of physical properties. After presenting a preliminary validation against experimental data for a <span><math><mi>n</mi></math></span>-decane static burning droplet, it is shown that the numerical simulations reproduce accurately different types of flame shapes. In particular, depending on the conditions, an envelope flame surrounding the droplet, a wake flame attached at the rear of the droplet or side flame, which is an intermediate state between the previous two regimes, are observed. The numerical results clearly demonstrate the strong effect of the different flame shapes on the Nusselt number of the evaporating droplet. The Nusselt number tends to decrease during the transition between the envelope flame to the wake flame, exhibiting a non-monotonic behavior for increasing Reynolds numbers. These results are significant since classical correlations on the Nusselt number assumes a monotonic increase for increasing Reynolds numbers, and thus miss the effect of the transition between the envelope flame to the wake flame. Finally, the solver developed for the sake of this study, presents many potentialities to explore more complex configurations than isolated and spherical droplets. Indeed, the overall numerical methodology enables to handle any interface shape and topology, and can be relevant to study collective effects, as the combustion of droplet groups, for instance.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"24 ","pages":"Article 100400"},"PeriodicalIF":5.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"From pure H2 to H2–CO2 mixtures: A study of reductant strategies in plasma iron smelting reduction","authors":"Jordan N. Figueiredo,&nbsp;Bassam B. Dally,&nbsp;Deanna A. Lacoste","doi":"10.1016/j.jaecs.2025.100401","DOIUrl":"10.1016/j.jaecs.2025.100401","url":null,"abstract":"<div><div>Hydrogen plasma offers an emerging route for carbon-free iron oxide reduction, but typical inert gas dilution limits industrial applicability. This study explores pure hydrogen and hydrogen–carbon dioxide plasma for in-flight hematite reduction in atmospheric elongated arc discharge. Pure hydrogen yields the lowest power consumption, but reduced plasma stability and limited conversion. CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> addition enhances stability, increasing gas temperature from approximately 1900<!--> <!-->K (pure H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>) to 2900 K at 50% CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> driven by exothermic H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> oxidation. Particle rapidly reach gas temperature (<span><math><mo>&gt;</mo></math></span>2000 K within 5 ms). The highest metallization degree (<span><math><mo>≈</mo></math></span>37%) achieved at 30% CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, corresponds to an optimal reductant gas composition balancing hydrogen, carbon monoxide, and atomic hydrogen availability. Higher dilution (50% CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>) significantly decreased the reductant gas availability, lowering the degree of reduction despite higher temperatures. These insights demonstrate that controlled CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> co-feeding and regeneration optimize plasma stability, temperature, and reductant gas chemistry, presenting a promising approach towards scalable and energy-efficient hydrogen plasma smelting reduction for sustainable metallurgy with a CO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> closed loop.</div></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"24 ","pages":"Article 100401"},"PeriodicalIF":5.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}