Combustion and Flame最新文献

{"title":"Ammonium dinitramide (ADN)-based hydroxyl-terminated polybutadiene (HTPB) propellant prepared by dimeryl diisocyanate (DDI)","authors":"Kai Xin,&nbsp;Yuanlu Cui,&nbsp;Zheng Huo,&nbsp;Ju Li,&nbsp;Kairui Yang,&nbsp;Chong Teng,&nbsp;Jianmin Li,&nbsp;Jinxian Zhai,&nbsp;Rongjie Yang","doi":"10.1016/j.combustflame.2025.114178","DOIUrl":"10.1016/j.combustflame.2025.114178","url":null,"abstract":"<div><div>Toluene diisocyanate (TDI) reacts with ammonium dinitramide (ADN), and isophorone diisocyanate (IPDI) adversely affects the thermal stability of ADN, which limits the application of ADN in hydroxyl‑terminated polybutadiene (HTPB) propellant. Due to the low toxicity and good physicochemical properties, dimeryl diisocyanate (DDI) is a good alternative for HTPB propellant. It was found that DDI is compatible with ADN, and HTPB/ammonium perchlorate (AP)/ADN/Al propellant cured by DDI was successfully prepared. Compared with HTPB/AP/Al and HTPB/AP/cyclotrimethylene trinitramine (RDX)/Al propellants, HTPB/AP/ADN/Al propellant has the lowest density, but the highest heat of combustion and theoretical specific impulse, which is related to the low density, high oxygen balance, high gas production and high energy of ADN. The addition of ADN promotes the low-temperature decomposition of AP in propellant, shortens the ignition delay time, and improves the burning rate and burning rate-pressure exponent. RDX and ADN have lower melting point and decomposition temperature, and release a lot of heat during decomposition, so it is easier to form a molten layer on the combustion surface, which promotes the Al agglomeration. However, the high gas production of ADN inhibits the Al agglomeration to some extent. The proportion of agglomerates in condensed combustion products of HTPB/AP/ADN/Al propellant is 5.11 % lower than that of HTPB/AP/RDX/Al propellant, and its size is also smaller. The Al content of condensed combustion products of HTPB/AP/ADN/Al propellant is nearly 1/3 lower than that of HTPB/AP/RDX/Al propellant. DDI is a curing agent suitable for ADN-based HTPB propellant, and compared with nitroamine explosives with negative oxygen balance such as RDX, ADN has many advantages in HTPB system.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"277 ","pages":"Article 114178"},"PeriodicalIF":5.8,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143873174","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":"Exploring high-temperature interaction between NH3/H2 blends and NO in laminar flame propagation: Insight into the competition between H-NO and NHx-NO mechanisms","authors":"Jianguo Zhang ,&nbsp;Jun Fang ,&nbsp;Tianyou Lian ,&nbsp;Sibo Han ,&nbsp;Jiabiao Zou ,&nbsp;Wei Li ,&nbsp;Yuyang Li","doi":"10.1016/j.combustflame.2025.114181","DOIUrl":"10.1016/j.combustflame.2025.114181","url":null,"abstract":"<div><div>Ammonia (NH₃) co-firing with hydrogen (H₂) and NH₃ pre-cracking are widely adopted combustion enhancement strategies for NH₃ applications in practical combustion devices, raising a growing need to understand the high-temperature interaction of NH₃/H₂ blends and nitric oxide (NO), which is critical for NO reduction mechanism. In this work, the oxygen-free outwardly propagating spherical flame method is used to investigate the laminar flame propagation of NH₃/H₂/NO and NH₃/H₂/NO/N₂ mixtures at 1 atm and 298 K. A non-monotonic behavior of laminar burning velocities (LBVs) of NH₃/H₂/NO mixtures with increasing H₂ content is observed. A kinetic model of NH₃/H₂/NO combustion is constructed and validated against the new data in this work and previous data in literature. Rate of production analysis, sensitivity analysis and updated fictitious diluent gas method are adopted to reveal the critical combustion chemistry in NH₃/H₂/NO flames with insight into the competition between H-NO and NH_x-NO mechanisms. The non-monotonic variation of LBVs can be attributed to the competition between thermal effect and chemical effect. The controlling mechanism of NO reduction and the sensitive mechanism of laminar flame propagation are revealed to be strongly dependent on fuel compositions and equivalence ratios. H-NO and NH₂-NO mechanisms both play important roles in lean NH₃/NO flame. With the increase of H₂ content, the contributions of NH_x-NO mechanisms to NO reduction and the sensitivity coefficients decrease, while the contribution of H-NO mechanism follows a reverse order. Under rich conditions, NH₂-NO mechanism has exclusively high sensitivity coefficients in NH₃/NO flames, while its rapidly decreasing significance and the increasing importance of H-NO mechanism with the increasing H₂ content leads to transitions in the most sensitive mechanism of laminar flame propagation at 0.5-0.7 H₂ contents. Compared with H-NO and NH₂-NO mechanisms, the NH-NO mechanism has negligible sensitivity coefficients, because its key reactions are mainly chain propagation reactions.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"277 ","pages":"Article 114181"},"PeriodicalIF":5.8,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868563","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 trace amount of Nitric Oxide (NO) addition on ammonia autoignition in a rapid compression machine","authors":"Gabriel J. Gotama ,&nbsp;Yueying Liang ,&nbsp;Liang Yu ,&nbsp;Yongxiang Zhang ,&nbsp;Wei Zhou ,&nbsp;Zimu Wang ,&nbsp;Yi Yang ,&nbsp;Xingcai Lu","doi":"10.1016/j.combustflame.2025.114182","DOIUrl":"10.1016/j.combustflame.2025.114182","url":null,"abstract":"<div><div>Nitric oxide (NO) is an important product and a major intermediate species in ammonia combustion. This paper investigates the impact of NO on ammonia oxidation in a rapid compression machine. Ignition delay times are measured under stoichiometric and lean (φ = 0.5) conditions with 0 to 2000 ppm NO addition at 25 - 40 bar and 1080 - 1200 K. Due to a small fraction of NO converted to nitrogen dioxide (NO₂) during the reactant preparation, the investigation can be considered as simultaneous doping with NO and NO₂ where the NO₂ can be quantified using simulation. The addition of NO (and the converted NO₂) consistently promotes ammonia autoignition where the ignition delay can be reduced by up to a factor of 6. This NO promotion behaviour was consistent across the pressures investigated. A kinetic model was developed using recent updates on elementary reactions, which improves the simulation compared to existing models. Analysis using the developed model indicated that NO addition enhances the HO₂ production via reaction H₂NO + O₂ = HNO + HO₂, and HNO + O₂ = NO + HO₂, which provide an abundant supply of HO₂ for reaction NO + HO₂ = NO₂ + OH and keep high OH production all the way to autoignition. The impact of pure NO is also isolated using simulation. The results indicate that NH₃ is unique in that higher NO invariably leads to shorter ignition delay which does not show the saturation effect as previously reported for hydrocarbon/NO and H₂/NO cases.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"277 ","pages":"Article 114182"},"PeriodicalIF":5.8,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143873173","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":"In Situ high spatiotemporal imaging of Al-Li microparticles in levitated combustion","authors":"Xu Wang ,&nbsp;Yongqi Liu ,&nbsp;Xu Xu ,&nbsp;Liu Dazhi ,&nbsp;Qingchun Yang","doi":"10.1016/j.combustflame.2025.114194","DOIUrl":"10.1016/j.combustflame.2025.114194","url":null,"abstract":"<div><div>The ability to observe micron-sized particle combustion with high temporal and spatial resolution is essential for advancing fundamental combustion models and understanding critical processes in extreme environments, such as those required for in-situ resource utilization on Mars. However, achieving high resolution through non-intrusive methods remains a significant challenge. We demonstrated a high temporal (∼10 µs) and spatial (∼700 nm/px) resolution, non-contact combustion setup for observing Al-Li particle combustion. The presence of 5 % lithium in Al-Li particles leads to enhanced ignition and combustion rates. This improvement is attributed to lithium’s low melting and boiling points, which significantly reduce combustion time compared to pure aluminum particles. Additionally, a power law relationship between particle size and combustion time is maintained. The initial alumina cap forms through molten alumina surface convection, leading to asymmetric flames and rapid particle rotation. During steady combustion, high-precision observations reveal that the alumina cap covers 30 % of the surface with a contact angle of approximately 35.9°. Under high-pressure conditions, the condensed-phase products agglomerating around the aluminum droplet collide with the rapidly rotating alumina cap. This impact causes the molten alumina cap to fracture and splash, reducing its coverage of the aluminum droplet and thereby accelerating the combustion process of the particle.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"277 ","pages":"Article 114194"},"PeriodicalIF":5.8,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143873164","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":"Formation mechanism and kinetics of Ni3CuN complex nitride in solution combustion synthesis","authors":"Marieta K. Zakaryan ,&nbsp;Narine H. Amirkhanyan ,&nbsp;Suren L. Kharatyan ,&nbsp;Ani Aprahamian ,&nbsp;Khachatur Manukyan","doi":"10.1016/j.combustflame.2025.114195","DOIUrl":"10.1016/j.combustflame.2025.114195","url":null,"abstract":"<div><div>This study investigates the formation mechanism of Ni₃CuN complex nitride during combustion of aqueous solutions of nickel and copper nitrates and hexamethylenetetramine. The impact on the combustion process and final product formation was analyzed by varying the hexamethylenetetramine concentration. Time-temperature measurements during solution combustion synthesis (SCS) reactions coupled with X-ray diffraction (XRD), transmission electron microscopy, electron diffraction, and high-resolution element analysis of reacted materials revealed a complex reaction mechanism. Thermogravimetric analysis (TGA) provided detailed insights into the combustion dynamics, identifying several distinct stages: partial dehydration of metal nitrates, decomposition of intermediate nitrates forming oxides, metal and alloy formation, and final nitridation to produce Ni₃CuN. The TGA results highlighted the significant influence of heating rate on reaction dynamics, with lower rates (0.083–0.25 K/s) leading to gradual weight loss and higher rates (0.33–0.5 K/s) resulting in abrupt reactions. The effective activation energy calculations from TGA data, supported by XRD and electron microscopy findings, identified nickel nitrate decomposition as the rate-limiting step, with an effective activation energy of 179 ± 27 kJ/mol for lower heating rates and 217 ± 36 kJ/mol for higher rates. These integrated analyses enhance the understanding of the SCS mechanism for synthesizing Ni₃CuN and demonstrate the potential for producing complex nitrides with tailored properties for applications in catalysis, magnetic devices, and other advanced materials technologies.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"277 ","pages":"Article 114195"},"PeriodicalIF":5.8,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868562","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":"Thermodynamic trajectories in detonations with stratified reactant mixtures","authors":"Michael Ullman ,&nbsp;Ral Bielawski ,&nbsp;Venkat Raman","doi":"10.1016/j.combustflame.2025.114173","DOIUrl":"10.1016/j.combustflame.2025.114173","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Incomplete mixing of non-premixed reactants has been cited as a potential cause for non-ideal wave strengths and combustion efficiencies in detonation-based combustors. To isolate the effects of mixture inhomogeneities, this work considers two-dimensional simulations of detonations in channels with stratified reactants. Stratification is imposed using the equivalence ratio of H&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;-air, which is prescribed with varying integral length scales. Adaptive mesh refinement and detailed chemical kinetics are used to capture the shocks and reaction zones at high spatiotemporal resolution. Increasing stratification yields larger and more irregular detonation cells, but only 3% deficits in mean wave speed from the mean mixture CJ speed. To examine the disparate local fluidic and thermodynamic processes contributing to the macroscopic wave dynamics, Lagrangian tracer “particles” are propagated with the local fluid velocity at simulation runtime. Statistics for particle trajectories are conditioned on the initial reactant composition (rich vs. lean) and local wave strength (over- vs. under-driven), allowing the effects of reactant mixedness and wave instabilities to be directly examined. Increasing stratification primarily affects the mean trajectories for rich and lean particles, as stratification partitions heat release between the different mixture compositions. This leads to larger discrepancies in mean temperature, total heat release, and the locations of the CJ points in &lt;span&gt;&lt;math&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;–&lt;span&gt;&lt;math&gt;&lt;mi&gt;v&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; space. However, the CJ points for rich and lean particles are located at roughly the same distances from the wave fronts. In addition, over- and under-driven particles experience nearly the same total heat release and entropy generation, but over-driven undergo greater shock losses while under-driven undergo greater heating losses. These results illustrate how the interplay of unsteady localized thermodynamic processes contribute to the global wave dynamics and mean post-detonation state, which are found to be reasonably well-approximated by the ZND solution for the mean mixture composition.&lt;/div&gt;&lt;div&gt;&lt;strong&gt;Novelty and Significance Statement&lt;/strong&gt;&lt;/div&gt;&lt;div&gt;The Lagrangian analyses in this work provide direct access to the unsteady and highly localized processes contributing to the non-ideal dynamics of detonations in inhomogeneous reactant mixtures. This distinguishes the present work from others on stratified detonations, which have primarily analyzed wave dynamics in the Eulerian reference frame. To the authors’ knowledge, this work is the first to incorporate Lagrangian analyses into simulations of detonations with stratified fuel-air mixtures. The conditioning of particle trajectories on the initial reactant composition and local wave strength is also a methodological innovation. The results contribute to the fundamental und","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"277 ","pages":"Article 114173"},"PeriodicalIF":5.8,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868564","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":"Combustion promotion of aluminum-water propellant via ternary metastable intermolecular complexes","authors":"Yao Shu,&nbsp;Lu Liu,&nbsp;Zhiwei Li,&nbsp;Peijin Liu,&nbsp;Wen Ao","doi":"10.1016/j.combustflame.2025.114193","DOIUrl":"10.1016/j.combustflame.2025.114193","url":null,"abstract":"<div><div>This paper addresses the issue of poor combustion performance of aluminum-water propellant by investigating the promotion mechanism of ternary metastable intermolecular complexes (MICs) on the performance of thermal decomposition, combustion, and agglomeration of aluminum-water propellant through a range of experimental techniques. An experimental study was firstly conducted to investigate the promotion of aluminum-water propellant combustion by Bi₂O₃ and polyvinylidene fluoride (PVDF). The findings indicate that Bi₂O₃ and PVDF augment the reactivity and reaction heat of aluminum powder, Bi₂O₃ was helpful for the combustion efficiency of the aluminum particles, and PVDF was more effective in inhibiting agglomeration and increasing the burning rate. Subsequently, an investigation was conducted to ascertain the promotional effect of Al/PVDF/Bi₂O₃ MICs on the combustion performance of aluminum-water propellant. The findings demonstrated that the activity of aluminum powder with ternary MICs was markedly enhanced, with a significant increase in the mass burning rate of the aluminum-water propellant (up to 70 %) and combustion efficiency (up to 13.5 %). Furthermore, the ternary MICs demonstrated superior inhibition of agglomeration compared to Al/Bi₂O₃ MICs. Finally, we preliminarily proposed the mechanism of action of MICs on combustion promotion of aluminum-water propellants. The mechanism of combustion promotion of PVDF and Bi₂O₃ on aluminum-water propellants is not simply the superposition of two mechanisms, but plays a role of mutual promotion, and better performance enhancement of combustion. In conclusion, the results of this study demonstrate that Al/PVDF/Bi₂O₃ MICs can markedly improve the combustion performance of aluminum-water propellants. The findings of this study, along with the experimental data and insights gained, can inform the development of advanced aluminum-water propellants for a range of propulsion and energy applications.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"277 ","pages":"Article 114193"},"PeriodicalIF":5.8,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143867890","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":"Understanding the chemical pathways of NO formation in low-pressure burner stabilized premixed lean-to-rich hydrogen flames","authors":"Tirthankar Mitra,&nbsp;Nathalie Lamoureux,&nbsp;Pascale Desgroux","doi":"10.1016/j.combustflame.2025.114192","DOIUrl":"10.1016/j.combustflame.2025.114192","url":null,"abstract":"<div><div>Hydrogen (H₂) combustion, a potential clean energy solution, is hindered by NO emission that affects human health and the environment. A comprehensive understanding of NO formation during H₂ combustion is necessary to mitigate its emission. The dynamic interplay between the different formation pathways makes the interpretation of NO sub-mechanism difficult. Lack of comprehensive experimental data further limits the comprehension of NO formation process, especially for the non-thermal NO formation pathways. In this study, quantitative NO and temperature measurements were performed using in-situ laser diagnostics in 6 low-pressure burner stabilized H₂/O₂/N₂ flames over a wide range of equivalence ratios (0.35–1.50) at 35 and 70 Torr (4.67, and 9.33 kPa). The maximal temperature in the flames remain below 1500 K, which minimizes the thermal NO pathway and allows for a focused study of non-thermal pathways of NO formation. However, the low temperature restricts NO formation imposing severe challenges on experimental measurements. Several precautions were taken to address these challenges and reduce the experimental uncertainty. The maximal NO mole fraction in the flames is between 0.09 and 0.71 ppm. The experimental re-evaluation of two flames similar to Harrington (Harrington et al., Proc. Combust. Inst., 26, 1996) shows disagreement with the original experimental data but consistent with the simulation predictions. This re-evaluated dataset can potentially replace the existing controversial Harrington measurements for validation of NNH pathway. The simulations of the flames using three recent chemical kinetic models predict NO in satisfactory agreement with the experiment, even for the flames similar to Harrington. The study suggests that NNH pathway dominates NO formation in low-pressure, low temperature H₂ combustion irrespective of the equivalence ratio. The large set of novel experimental datasets generated in this study can serve as future chemical kinetic model validation targets, especially for the NNH pathway of NO formation.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"277 ","pages":"Article 114192"},"PeriodicalIF":5.8,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863722","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 delay time and methane time history in hydrogen-natural gas surrogate blends: A shock tube study","authors":"Wanting Jia ,&nbsp;Shubao Song ,&nbsp;Lin Zhang ,&nbsp;Cheng Wang ,&nbsp;Pavel Krivosheyev ,&nbsp;Dongping Chen ,&nbsp;Jiankun Shao","doi":"10.1016/j.combustflame.2025.114191","DOIUrl":"10.1016/j.combustflame.2025.114191","url":null,"abstract":"<div><div>The pipeline transportation of hydrogen-blended natural gas offers an efficient large-scale solution while introducing new safety and technical challenges. This study investigates the combustion characteristics of hydrogen-natural gas blends, using pure methane and a 1% C₃H₈/99% CH₄ mixture as natural gas surrogates. Ignition delay times and methane time histories were measured in a shock tube for hydrogen–natural gas surrogate blends containing 10 %, 20 % and 30 % hydrogen (by mole fraction of the fuel component) at 1305–1729 K, 1 atm, and equivalence ratios of 0.5, 1.0 and 2.0. High-precision in-situ methane concentration data were obtained using 3175 nm laser absorption diagnostics. The results indicate that hydrogen addition significantly enhances methane consumption rate and overall reactivity. The Aramco Mech 3.0, NUIG Mech 1.3, FFCM-2, USC Mech Ⅱ and GRI Mech 3.0 kinetic models were evaluated against the present experimental data. The rate constants of three key reactions in the Aramco Mech 3.0, NUIG Mech 1.3, and FFCM-2 kinetic models were revised, resulting in simulation results that show improved agreement with the experimental data for ignition delay times and methane time histories. This study provides both experimental and modeling studies on the combustion characteristics of hydrogen-natural gas blends, contributing to the safe transportation and utilization of hydrogen.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"277 ","pages":"Article 114191"},"PeriodicalIF":5.8,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868561","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":"Temperature field measurement of a burning aluminum droplet","authors":"Hugo Keck ,&nbsp;Christian Chauveau ,&nbsp;Guillaume Legros ,&nbsp;Stany Gallier ,&nbsp;Fabien Halter","doi":"10.1016/j.combustflame.2025.114163","DOIUrl":"10.1016/j.combustflame.2025.114163","url":null,"abstract":"<div><div>In a diffusive combustion regime, an aluminum droplet undergoing combustion forms an oxide cloud that surrounds the burning droplet. Thorough characterization of this cloud is crucial to the validation of the subsequent modeling. This paper makes a significant contribution to the field by providing an experimental procedure to resolve the spatial temperature profile within the oxide cloud. An electrodynamic levitator is used to observe the self-sustained combustion of aluminum particles with a radius of <span><math><mrow><mn>35</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span> in atmospheric air, with negligible convective effects. The levitating device is coupled to an optical apparatus that allows for a light extinction method, thereby enabling the determination of size and concentration profiles of the nanometric alumina droplets, as introduced in previous works. The data from the previous study are employed in conjunction with a modulated absorption–emission (MAE) technique to ascertain a temperature profile that does not rely on the grey-body assumption. This technique is further enhanced by an optimization method to account for gaseous phase emissions, which typically hinder conventional temperature evaluation. Consequently, a spatially resolved temperature profile of the oxide cloud surrounding the burning droplet is obtained. Close to the surface of the droplet, a temperature of 2580 K is assessed. Then, a maximum temperature of about 3615 K is measured. As an additional outcome, gaseous emission profiles are obtained for three wavelengths and exhibit a notable correlation with a simulated gaseous suboxide concentration profile. The results presented in this work demonstrate a relatively high degree of consistency with expected temperatures.</div><div><strong>Novelty and Significance Statement</strong></div><div>This work presents a novel experimental method to obtain an unique temperature profile surrounding an isolated aluminum droplet in combustion. In conjunction with previous work, a non-intrusive, complete, and instantaneous characterization of the oxide smoke is now made possible, with the addition of the temperature profile to the known alumina particle size and concentration profiles. This comprehensive data set is presented for a fundamental case of a single levitating particle. The incorporation of the temperature profile provides an incomparable insight into alumina condensation processes and a detailed reference case for simulation purposes. The results presented in this work document the intricate condensation process of nanoparticles and highlight the limitations of current simulation methods.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"277 ","pages":"Article 114163"},"PeriodicalIF":5.8,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143860000","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}