Combustion and Flame最新文献

{"title":"A comparative study on the effects of NO2 addition on the auto-ignition behavior of n-heptane, iso-octane and toluene at engine relevant conditions","authors":"Shijun Dong ,&nbsp;Da Yao ,&nbsp;A. Abd El-Sabor Mohamed ,&nbsp;Jinhua Li ,&nbsp;Wenxue Gao ,&nbsp;Yang Cao ,&nbsp;Zhaowen Wang ,&nbsp;Jinhu Liang ,&nbsp;Henry J. Curran ,&nbsp;Xiaobei Cheng","doi":"10.1016/j.combustflame.2025.114118","DOIUrl":"10.1016/j.combustflame.2025.114118","url":null,"abstract":"<div><div>It is necessary for gasoline surrogate models to simulate the effect of NOx addition on fuel auto-ignition behavior, as NOx can affect engine combustion via exhaust gas recirculation (EGR). Toluene is often used as a representative aromatic component in gasoline surrogate models, and hence it is important to investigate the effect of NOx addition on its auto-ignition behavior and to fully understand the interaction chemistry between toluene and NOx. In this paper, high-pressure shock tubes and a rapid compression machine are used to measure the ignition delay times (IDTs) of toluene in ‘air’ mixtures with and without the addition of nitrogen dioxide (NO₂), at a pressure of 20 atm and at temperatures in the range 600–1400 K. The IDTs of <em>n</em>-heptane, <em>iso-</em>octane and a mixture of toluene/<em>n</em>-heptane/<em>iso-</em>octane are measured at the same conditions for comparison. The experimental results show that the auto-ignition behavior of toluene exhibits significantly different sensitivity to NO₂ addition compared to <em>n</em>-heptane and <em>iso-</em>octane. NO₂ significantly promotes the reactivity of toluene at low temperatures (600–1000 K), in which the IDTs decreased by two orders of magnitude when 1000 ppm of NO₂ is added, whereas there is an order of magnitude decrease with the addition of 200 ppm NO₂. The promoting effect of NO₂ on toluene oxidation reduces significantly at temperatures above 1000 K. The experimental results also show that NO₂ addition exhibits a slight promoting effect on the reactivity of <em>n</em>-heptane and <em>iso-</em>octane at temperatures above 750 K at the conditions studied. A kinetic model is proposed based on C3MechV3.3 in which the interaction chemistry between these gasoline surrogates and NOx is updated. The proposed kinetic model can simulate well the effect of NO₂ addition on the auto-ignition behavior of these surrogates. Flux and sensitivity analyses are performed to highlight the important interaction reaction pathways.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"276 ","pages":"Article 114118"},"PeriodicalIF":5.8,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684403","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":"Two dimensional flame structure of oscillating burner-stabilized methane-air flames","authors":"Ningyi Li ,&nbsp;Viatcheslav Bykov ,&nbsp;Anastasia Moroshkina ,&nbsp;Evgeniy Sereshchenko ,&nbsp;Vladimir Gubernov","doi":"10.1016/j.combustflame.2025.114115","DOIUrl":"10.1016/j.combustflame.2025.114115","url":null,"abstract":"<div><div>The highly transient relaxational diffusive-thermal oscillations of flat burner-stabilized flames can be very attractive to probe the performance of detailed reaction mechanisms in the regimes close to ignition/extinction. In such regimes, certain reaction zones can travel over distances of the order of 10 mm and this raises an important question if one dimensional numerical models can be accurate in describing them. The question of quantitative comparison of modeling and experiments becomes crucial to study, to understand these regimes and to utilize them for validation. In this work, we experimentally investigate relaxational oscillations of methane-air flames on a flat porous burner with a surrounding nitrogen co-flow and perform fully resolved 2D numerical simulations of the same burner configuration, using a detailed reaction mechanism and molecular diffusion model, buoyancy and radiation, alongside corresponding experiments. The focus is on the effect of the nitrogen co-flow on the flame oscillations, which can only be studied numerically in 2D simulations due to the mutual effect of the complex flow field and flame dynamics. The results of both numerical and experimental approaches are found to be in quantitative agreement. They show that there is an optimal co-flow velocity that removes the secondary diffusion flame and extinguishes the edge flame settled in the stagnation flow region. This optimal regime makes the flame flatter and closer to a one-dimensional configuration and this is a most favorable condition for validation of kinetic mechanisms. The detailed data from the simulations will guide the design of the next generation of the burner configurations to study the kinetics and dynamics of complex fuels required for a sustainable energy transition.</div><div><strong>Novelty and Significance Statement</strong></div><div>The novelty of this research lies in the synergy of these modeling, computations with experimental measurements, allowing both parametric studies of the oscillation regime and deeper insights into the flame structure. These results are significant because they allow to develop more accurate burner configurations for studying flames near extinction and ignition conditions, which will be an important task for more complex fuels from renewable sources required for a sustainable energy transition. Ultimately, our understanding of the interplay between chemistry and diffusion controlled combustion regimes under transient conditions can be approved and validation data for e.g. chemical reaction mechanisms can be generated. The latter becomes extremely important since efficiency and pollutant mitigation issues require lean and chemistry controlled combustion processes used in the combustion facilities. Thus understanding, optimization and control of such regimes has become a crucial point for further development of the sustainable combustion.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"276 ","pages":"Article 114115"},"PeriodicalIF":5.8,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of combustion behavior and regression rate of hypergolic solid fuels in counterflow spray experiment","authors":"Wei-Che Lin ,&nbsp;Ray Peterson ,&nbsp;Michael J. Bortner ,&nbsp;Gregory Young","doi":"10.1016/j.combustflame.2025.114132","DOIUrl":"10.1016/j.combustflame.2025.114132","url":null,"abstract":"<div><div>Recent studies have shown the advantages of hypergolic solid fuels in hybrid rockets, particularly their short ignition delays and simplified designs. However, research on their combustion behavior and regression rates remains limited. This study attempts to address some of these gaps using low-density polyethylene-based fuels embedded with sodium borohydride and 90 wt% hydrogen peroxide as the oxidizer. A modified counterflow spray experiment was employed, revealing unique combustion features and surface structures, such as char spots and bulges. A novel technique was developed to measure the fuel regression rate under an oxidizer spray, yielding averages between 0.39 to 0.52 mm/s at oxidizer mass flow rates of 0.38 to 0.43 g/s, significantly higher than those obtained with oxygen counterflow burners. Regression rates increased with higher flow rates and additive concentrations, primarily due to enhanced surface reactions. The measured combustion delay times were considerably longer than the ignition delay times observed in droplet tests, highlighting the importance of evaluating ignition performance under spray conditions. Reignition tests revealed longer ignition and combustion delay times compared to the first ignition, with averages increasing from 23 to 162 ms and 158 to 342 ms, respectively. Thermochemical analysis and Fourier transform infrared spectroscopy (FTIR) identified the char layer as primarily sodium metaborate tetrahydrate, which is identified as a cause for its reduced reactivity with the oxidizer during reignition.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"276 ","pages":"Article 114132"},"PeriodicalIF":5.8,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684401","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":"Modeling and validation: A comprehensive and robust surrogate kinetic model for oxidation of various biodiesels","authors":"Lalit Y. Attarde,&nbsp;Krithika Narayanaswamy","doi":"10.1016/j.combustflame.2025.114109","DOIUrl":"10.1016/j.combustflame.2025.114109","url":null,"abstract":"<div><div>In recent years, there has been a notable surge in experimental and kinetic modeling efforts concerning various biodiesels, their surrogates, and relevant molecules. This work culminates these research efforts to construct a comprehensive and robust surrogate kinetic model for various biodiesel fuels. This model has incorporated accurate chemistry and undergone extensive validation against a broad range of experimental data available for biodiesel. In order to accurately reproduce the combustion characteristics of biodiesel, methyl butanoate, methyl crotonate, 3-hexene, and n-dodecane are chosen as surrogate components. These molecules have been chosen to replicate the functional groups found in biodiesel methyl esters. Each surrogate component is firstly validated thoroughly against a wide array of experimental studies. The kinetics of each component are improved through careful rate assignments derived from various theoretical investigations. Subsequently, a surrogate mixture comprising these selected components is formulated by matching the functional groups of target fuels. This surrogate mechanism is used to validate the experimental data associated with various biodiesel fuels, their constituents, and methyl esters exhibiting similar functional groups to those present in actual biodiesel. The current kinetic model has demonstrated good agreement for various biodiesel fuels and their commonly used surrogates for a range of experimental studies, encompassing ignition delay times measured in shock tubes and rapid compression machines, laminar flame speeds, as well as species mole fractions measured in jet stirred reactors and laminar flow reactors.</div><div><strong>Novelty and significance statement</strong></div><div>This study introduces novel surrogate mixtures consisting of methyl butanoate, methyl crotonate, 3-hexene, and n-dodecane, formulated to predict the combustion characteristics of biodiesel. While several surrogate formulations for biodiesel exist in the literature, the novelty of this work lies in its extensive validation and reliable kinetic of the surrogate mixtures, which is leveraged from well-validated chemistry of each of these individual components. The study investigates whether selected small methyl esters and alkene can sufficiently capture combustion characteristics of molecules with similar functional groups. Currently, there are only two comprehensive biodiesel kinetic models in the literature, both developed over a decade ago, which have been widely used in subsequent studies for optimization and reduction. The new model presented in this study offers a more reliable chemistry while being relatively more compact, owing to its use of well validated small molecule surrogate components.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"276 ","pages":"Article 114109"},"PeriodicalIF":5.8,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684404","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 characteristics and primary particle size of soot in ethylene/propylene-air coflow flames under dynamic pressure rise environment","authors":"Jingru Zheng ,&nbsp;Xiaolei Zhang ,&nbsp;Suk Ho Chung ,&nbsp;Longhua Hu","doi":"10.1016/j.combustflame.2025.114113","DOIUrl":"10.1016/j.combustflame.2025.114113","url":null,"abstract":"<div><div>The effect of dynamic pressure rise rate on the burning characteristics and soot particle size in laminar coflow flames of ethylene and propylene is studied. Flame characteristics are observed at constant fuel flow rates under five pressure rise rates. Soot particles are collected using a thermophoretic sampling method at a pressure of 65 kPa during the pressure increase, and the primary soot particle diameters in ethylene flames are measured using a transmission electron microscope (TEM). The results show that the flame height increases with chamber pressure until 65 kPa, then slightly decreases. The flame becomes shorter with a higher pressure rise rate, influenced by both diffusion and buoyancy effects. As pressure increases, the transverse diffusion of fuel molecules diminishes, causing the flame to become slender. Simultaneously, the buoyancy effect enhances air entrainment, contributing to a reduction in flame height. A relationship between the flame height, pressure and dynamic pressure rise rate is derived based on the Burke-Schumann theory by assuming the pressure as a function of time. The proposed model can successfully predict the experimental data. The length of the soot-free main reaction zone (exhibiting a blue color) decreases with increasing pressure and is longer at smaller pressure rise rates. The relationship between the blue flame zone length and the dynamic pressure rise rate, which is characterized by soot formation time, correlates well with experimental results. The measured soot particle sizes range from 25 to 35 nm. The soot particle sizes are larger at lower pressure rise rates. The fractal dimension decreases with increasing pressure rise rates, while the pre-factor increases as the pressure rise rates become higher.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"276 ","pages":"Article 114113"},"PeriodicalIF":5.8,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684419","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 fundamental investigation of the pyrolysis chemistry of Oxymethylene Ethers. Part I: Quantum chemical calculations and kinetic model development","authors":"Kevin De Ras ,&nbsp;Olivier Herbinet ,&nbsp;Frédérique Battin-Leclerc ,&nbsp;Yann Fenard ,&nbsp;Luc-Sy Tran ,&nbsp;Guillaume Vanhove ,&nbsp;Joris W. Thybaut ,&nbsp;Kevin M. Van Geem","doi":"10.1016/j.combustflame.2025.114121","DOIUrl":"10.1016/j.combustflame.2025.114121","url":null,"abstract":"<div><div>Oxymethylene ethers (OMEs) have emerged as a promising and sustainable alternative for fossil-based fuels in recent years. This class of synthetic fuels can be produced from captured CO₂ with renewable electricity, so-called e-fuels, using carbon capture and utilization technology resulting in environmentally cleaner combustion. However, before OMEs can be used globally, it is essential to have a thorough understanding of their radical decomposition chemistry. In this study, combined experimental and kinetic modeling work is conducted to unravel the pyrolysis chemistry of oxymethylene ether-3 (OME-3), oxymethylene ether-4 (OME-4), and oxymethylene ether-5 (OME-5). A detailed kinetic model for pyrolysis of these long-chain OMEs with elementary reaction steps is developed based on first principles with the automatic kinetic model generation tool ‘Genesys’. The unimolecular decomposition pathways are explored by constructing potential energy surfaces, which highlight the importance of formaldehyde elimination reactions. In addition, rate rules are regressed for the unimolecular decomposition reactions of radicals, based on the quantum chemical results, to enable extrapolation of the kinetic data. The developed kinetic model is validated using experimental datasets from the literature, and benchmarking against other pyrolysis models demonstrates better predictive performance. The experimental observations are accurately predicted, on average within the uncertainty margin (∼10 mol% relative) for major compounds, without fitting model parameters. Part II of this study presents six newly acquired experimental datasets from jet-stirred and tubular reactors, additional kinetic model validation, and a comprehensive model analysis through rate of production and sensitivity analyses.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"275 ","pages":"Article 114121"},"PeriodicalIF":5.8,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682848","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":"Multi-phase hypergolic ignition model","authors":"David A. Castaneda ,&nbsp;Joseph K. Lefkowitz ,&nbsp;Benveniste Natan","doi":"10.1016/j.combustflame.2025.114114","DOIUrl":"10.1016/j.combustflame.2025.114114","url":null,"abstract":"<div><div>A novel approach for modeling hypergolic ignition is presented, validated, and used to successfully predict ignition delay times for a hybrid rocket propellant configuration. This configuration employs a hypergolic additive (sodium borohydride) that allows two non-hypergolic reactants (polyethylene and hydrogen peroxide) to gain hypergolic capabilities. The model considers multiple phases and multiple species, heterogeneous and homogeneous chemical reactions, mass transfer between phases, and heat transfer. The transient behavior of the various chemical and thermal properties involved in hypergolic ignition is studied. In addition, a parametric investigation is conducted to predict ignition delay times as functions of multiple variables such as additive loading, oxidizer concentration, and initial propellant temperatures, among others. The results are presented in the form of ignition delay time contour maps. The heat release rate is shown to be controlled mostly by hypergolic chemical reactions. Gas homogeneous reactions only take place during the last portion of the ignition process and are the ones responsible for ultimately leading to a gas thermal runaway. The proper inclusion of the vaporization and pyrolysis of the propellants is found to be crucial since these determine the formation of a gas phase, where ignition is achieved. It is found that the vaporization of the liquid oxidizer is the controlling mass transfer mechanism for the hybrid rocket configuration considered. The model successfully predicts the minimum hypergolic additive loading and the range of oxidizer-to-fuel ratios required for ignition. It is found that the optimal oxidizer-to-fuel ratio leading to the shortest ignition delay time is mostly a function of additive loading. In addition, it is found that pressure, propellant initial temperature, and oxidizer concentration, have a major influence on ignition delay times and that they barely affect the optimal oxidizer-to-fuel ratio. The presented model, although evaluated for the hybrid rocket configuration, is considered to be applicable for any hypergolic propellant configuration.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"276 ","pages":"Article 114114"},"PeriodicalIF":5.8,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental exploration of the N-containing soot precursors in C2H4-NH3 co-flow diffusion flames","authors":"Fei Ren,&nbsp;Zhuohang Li,&nbsp;Yezeng Fan,&nbsp;Jinze Li,&nbsp;Zhenyingnan Zhang,&nbsp;Ang Li,&nbsp;Zhan Gao,&nbsp;Lei Zhu,&nbsp;Zhen Huang","doi":"10.1016/j.combustflame.2025.114104","DOIUrl":"10.1016/j.combustflame.2025.114104","url":null,"abstract":"<div><div>The chemical effect of ammonia can reduce the formation of soot precursors in hydrocarbon fuel flames. The nitrogen from ammonia can combine with hydrocarbon species to reduce polycyclic aromatic hydrocarbons (PAHs) while forming nitrogen-containing polycyclic aromatic hydrocarbons (NPAH). In this work, an in-depth experimental investigation was conducted to identify the chemical effect of ammonia on the changes of N-containing functional groups in soot surface and the NPAH formation in C₂H₄-NH₃ co-flow diffusion flames. The X-ray photoelectron spectroscopy (XPS) and microscopic imaging infrared spectrometer (MIR) analysis were carried out to investigate the chemical composition of soot particles and determine the types and structural characteristics of functional groups on the soot surface. The results showed that ammonia addition increased the proportion of nitrogen and oxygen in soot and enriched the nitrogen/oxygen-containing functional groups on the soot surface. The soot sampled in ethylene flames with and without ammonia addition has similar chemical composition and surface functional groups. In particular, the aromatic C<img>N group was found in the soot from ethylene-ammonia diffusion flames. Also, the NPAH containing C<img>N bond was further determined through gas chromatography-mass spectrometry (GC-MS) analysis. The observed NPAH are mainly cyano substituted-PAHs such as 1-Naphthalenecarbonitrile (A2CN, m/z=153), 5-acenaphthylenecarbonitrile (A2R5CN, m/z=177), etc. It indicated that the active sites on the aromatic surface facilitated the binding of HCN and C<img>N bond to generate the cyano substituted-PAHs such as A2CN and A2R5CN. But the inhibitory effect of NPAH containing C<img>N bond on the formation of large PAHs and soot is limited. This experimental study confirmed that ammonia promoted the formation of NPAH containing C<img>N bond in soot.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"276 ","pages":"Article 114104"},"PeriodicalIF":5.8,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684397","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":"DDT run-up distance for stoichiometric hydrogen-methane-oxygen measured in an orifice plate filled tube","authors":"Chuanyu Pan ,&nbsp;Xishi Wang ,&nbsp;Gaby Ciccarelli","doi":"10.1016/j.combustflame.2025.114124","DOIUrl":"10.1016/j.combustflame.2025.114124","url":null,"abstract":"<div><div>Flame acceleration and deflagration-to-detonation transition (DDT) was studied in a 2.88-m, 7.6-cm inner-diameter transparent round tube filled with repeating 50 % blockage-ratio orifice plates. Stoichiometric hydrogen/methane/oxygen, with different hydrogen-to-methane mole ratios, and argon-diluted stoichiometric hydrogen-oxygen mixtures were tested. These mixtures span a range of detonation cell structure regularity. The reactivity of the mixture was controlled by varying the initial pressure, from the DDT critical pressure to a maximum of 40 kPa. Flame velocity was measured from high-speed video. The DDT run-up distance was obtained directly from the video images, and soot foils were used to confirm the DDT location at the critical initial pressure and to measure the detonation cell size at the end of the tube void of obstacles. The DDT run-up distance was shorter for methane containing mixtures at the lowest initial pressure near the DDT limit but was the same for all mixtures at pressures greater than 15 kPa. For each mixture, the DDT run-up distance decreased with the detonation cell size according to an inverse power-law. For a given detonation cell size, the DDT run-up distance decreases with increased methane-fraction. Therefore, for a given orifice diameter, at the DDT limit (where the orifice diameter roughly equals the detonation cell size), the DDT run-up distance for methane-containing mixtures is shorter than for 100 % hydrogen. This, and the fact that a higher initial pressure is required for methane containing mixtures to have the same cell size, needs to be considered when assessing the explosion hazard of hydrogen/methane mixtures.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"276 ","pages":"Article 114124"},"PeriodicalIF":5.8,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of hydroxypropyl methylcellulose and ferric chloride on hypergolic ignition of solidified ethanol fuels","authors":"Jerin John ,&nbsp;Purushothaman Nandagopalan ,&nbsp;Ankur Miglani ,&nbsp;Pranay Mudaliar ,&nbsp;Seung Wook Baek","doi":"10.1016/j.combustflame.2025.114126","DOIUrl":"10.1016/j.combustflame.2025.114126","url":null,"abstract":"<div><div>This study investigates the hypergolic ignition of reaction-driven solidified ethanol (RDSE) fuels, focusing on the effects of varying concentrations of hydroxypropyl methylcellulose (HPMC) gellant and ferric chloride (FeCl₃) dopant. Fourier Transform Infrared Spectroscopy (FTIR) and thermogravimetric analysis (TGA) are employed to examine molecular interactions and thermal properties. FTIR results indicate that no new covalent bonds are formed upon adding FeCl₃, whereas interactions primarily governed by weak hydrogen and ionic bonds. The apparent activation energy (<span><math><msub><mi>E</mi><mi>a</mi></msub></math></span>) has been determined for the fuel samples using iso-conversional model-free kinetics approach and found that <span><math><msub><mi>E</mi><mi>a</mi></msub></math></span> decreased with HPMC and FeCl₃ concentrations. Hypergolic ignition delay tests were attempted with the droplet study rocket grade hydrogen peroxide (90 % RGHP; H₂O₂) as an oxidizer, demonstrated that increasing HPMC concentration by 3 wt.% reduced ignition delay by ∼20 %, while a 5 wt.% increase in FeCl₃ concentration led to a ∼25 % reduction. Higher fuel temperatures enhanced the wetting and spreading behavior of H₂O₂ droplets, improving oxidizer-fuel interaction and reducing ignition delay. Overall, solidification of ethanol using HPMC with FeCl₃ eliminates the catalyst as FeCl₃ acts as both catalyst and binding agent.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"276 ","pages":"Article 114126"},"PeriodicalIF":5.8,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}