Applications in Energy and Combustion Science最新文献

{"title":"Furnace MILD combustion versus its open counterpart in hot coflow","authors":"X. Liu ,&nbsp;G. Wang ,&nbsp;J. Si ,&nbsp;M. Wu ,&nbsp;M.F. Hanif ,&nbsp;J. Mi","doi":"10.1016/j.jaecs.2024.100275","DOIUrl":"https://doi.org/10.1016/j.jaecs.2024.100275","url":null,"abstract":"<div><p>The open jet flame in hot co-flow (JHC) has been frequently utilized for fundamental investigations of Moderate or Intense Low-oxygen Dilution (MILD) combustion due to its controllable conditions and relatively easy measurement capabilities. However, practical MILD combustion must take place within a combustor that is enclosed. Therefore, it is necessary to examine the similarity and disparity of combustion characteristics between two flame configurations. This issue is addressed currently. Specifically, we investigate the flow mixing, ignition, and combustion, as well as emission characteristics of non-premixed and premixed JHC and cylindrical furnace (FUR) flames at various values of the environmental temperature (<em>T_e</em>) and central jet Reynolds number (<em>Re</em>). For the open non-premixed flames, we employ both previous single-tube JHC (SJHC) combustor and presently modified JHC (MJHC) one that uses the same nozzle configuration as the FUR burner. It is revealed that significant differences occur in flow, combustion and emission characteristics between the SJHC and FUR cases. On the other hand, both non-premixed and premixed MJHC configurations exhibit high similarity to the corresponding FUR cases in terms of upstream flow mixing and combustion features. Moreover, different CO and NO<em>_x</em> emissions result from open JHC and close furnace flames due to different post-combustion configuration and residence time. Accordingly, future experiments on non-premixed MJHC and premixed JHC flames are highly recommended for better understanding practical MILD combustion.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"19 ","pages":"Article 100275"},"PeriodicalIF":0.0,"publicationDate":"2024-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X2400030X/pdfft?md5=c98df884d8d37eea3fb9b6251afcc1b0&pid=1-s2.0-S2666352X2400030X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141163353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of differential diffusion in lean, premixed, hydrogen-enriched swirl flames","authors":"Benjamin Francolini ,&nbsp;Luming Fan ,&nbsp;Ehsan Abbasi-Atibeh ,&nbsp;Gilles Bourque ,&nbsp;Patrizio Vena ,&nbsp;Jeffrey Bergthorson","doi":"10.1016/j.jaecs.2024.100272","DOIUrl":"10.1016/j.jaecs.2024.100272","url":null,"abstract":"<div><p>Hydrogen combustion is a promising alternative to fossil fuel combustion in an effort to reduce our carbon footprint. However, hydrogen combustion is prone to thermodiffusive instabilities largely dependent on differential diffusion, a phenomenon that can lead to higher probabilities of flashback in industrial burners, given hydrogen’s high reactivity and diffusivity. This paper evaluates low-swirl flames of methane and air enriched with hydrogen to highlight the onset of differential diffusion. Testing was conducted in a fully controllable swirl burner, where bulk velocity <em>U</em><span><math><msub><mrow></mrow><mrow><mtext>av</mtext></mrow></msub></math></span> = 13 m/s and swirl number <em>S</em> = 0.6 were kept constant for each hydrogen–methane blend to isolate increases in flame surface area from increases in turbulence intensity. Furthermore, each fuel blend of hydrogen and methane is evaluated at the same laminar flame speed of <em>S</em><span><math><msubsup><mrow></mrow><mrow><mtext>L</mtext></mrow><mrow><mtext>o</mtext></mrow></msubsup></math></span> = 0.267 m/s to isolate flame stretch effects on the turbulent burning rate. Combined hydroxyl (OH) PLIF and stereoscopic PIV at the National Research Council of Canada were used to analyze the OH fluorescence in a 2D-3C velocity field for each flame condition. High-speed PIV at McGill University was used to resolve local flame phenomena, such as local flame displacement velocity and flame stretch rate. Using these techniques, it can be observed that the flame displaces axially in response to turbulent flame speed while exhibiting increases in flamefront wrinkling. This increased corrugation due to flame stretch is highlighted in the PDFs of local curvature and <span><math><mi>κ</mi></math></span><em>S</em><span><math><msub><mrow></mrow><mrow><mi>f</mi></mrow></msub></math></span> and is further evidenced by a shift towards positive curvatures (<span><math><mi>κ</mi></math></span> <span><math><mo>&gt;</mo></math></span> 0) for increasing H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> volume fraction. This trend suggests that there is a strong correlation with increases in turbulent burning rate and positive curvature as a result of differential diffusion, but it is not necessarily a control mechanism of the most forward propagating points proposed by <em>the theory of leading points</em>.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"18 ","pages":"Article 100272"},"PeriodicalIF":0.0,"publicationDate":"2024-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X2400027X/pdfft?md5=cc355b255e38ffd3de13eb4849fc00f6&pid=1-s2.0-S2666352X2400027X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141056644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enabling plastic waste gasification by autothermal chemical looping with > 90 % syngas purity for versatile feedstock handling","authors":"Eric Falascino ,&nbsp;Rushikesh K. Joshi ,&nbsp;Sonu Kumar,&nbsp;Tanay Jawdekar,&nbsp;Ishani K. Kudva,&nbsp;Shekhar G. Shinde,&nbsp;Zhuo Cheng,&nbsp;Andrew Tong,&nbsp;Liang-Shih Fan","doi":"10.1016/j.jaecs.2024.100270","DOIUrl":"10.1016/j.jaecs.2024.100270","url":null,"abstract":"<div><p>The chemical looping gasification of plastics (CLGP) is a process that offers an innovative solution for transforming post-consumer waste plastics into high-value products. The process utilizes a co-current moving bed reducer reactor with iron-titanium-based oxygen carriers to gasify plastic feed and generate syngas autothermally. Its distinguishing feature is its ability to operate over a wide range of feed loadings and co-injection of mixed plastic species without any performance losses. Isothermal bench-scale experiments reveal a syngas purity of ∼95 %, aligning with the thermodynamic simulations. The moving bed reactor facilitates a deeper reduction of the oxygen carriers to the Fe+FeTiO₃ phase, leading to the high syngas purity, which is then verified with additional TGA, XRD, and SEM analysis. For an autothermal operation of CLGP process, an active material content of 20 % is found to be sufficient to satisfy the kinetic and thermodynamic constraints. Further integration with downstream production of H₂ is presented and compared to a steam gasification process. The process integration simulations show that the CLGP process outperforms the steam gasification system in terms of Cold Gas Efficiency (CGE), Effective Thermal Efficiency (ETE), and H₂ yield. CO₂ emissions are impressively reduced by ∼30 % in the CLGP system over that in the steam gasification system due to its ability to autothermally operate the process, unlike the highly endothermic steam gasification process.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"19 ","pages":"Article 100270"},"PeriodicalIF":0.0,"publicationDate":"2024-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000256/pdfft?md5=2ca282e784178787361189692ab6b850&pid=1-s2.0-S2666352X24000256-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141023838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Industry R&D needs in hydrogen safety","authors":"Harri Kytömaa ,&nbsp;Achim Wechsung ,&nbsp;Georgios Dimitrakopoulos ,&nbsp;Neil Cook ,&nbsp;Daniel Jaimes ,&nbsp;In Young Hur ,&nbsp;Sahand Faraji","doi":"10.1016/j.jaecs.2024.100271","DOIUrl":"10.1016/j.jaecs.2024.100271","url":null,"abstract":"<div><p>Hydrogen's unique physicochemical and combustion properties make it stand out among fuels as new hydrogen production technologies, means of transportation, and consumers emerge. The future viability of these technological solutions will depend on numerous factors, including safety, environmental, regulatory, and economic considerations. Safe deployment of these technologies requires additional research and development activities. These range from an improved quantitative understanding of hydrogen leaks, material limitations due to embrittlement, very large-volume liquefied hydrogen storage and transport, to equipment- and usage-specific considerations as is the case for gas turbines and electrolyzers.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"18 ","pages":"Article 100271"},"PeriodicalIF":0.0,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000268/pdfft?md5=2b0520b1e4e3c053b04414f108a1f57c&pid=1-s2.0-S2666352X24000268-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141057495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Planar laser-induced incandescence for the study of soot production in a multi-sector RQL Jet A combustor","authors":"Russell McGrath ,&nbsp;Jeremiah Juergensmeyer ,&nbsp;Robert Bond ,&nbsp;Ezekiel Bugay ,&nbsp;Shawn Wehe ,&nbsp;David Wu ,&nbsp;Adam Steinberg ,&nbsp;Wenting Sun ,&nbsp;Yi Chen Mazumdar","doi":"10.1016/j.jaecs.2024.100269","DOIUrl":"https://doi.org/10.1016/j.jaecs.2024.100269","url":null,"abstract":"<div><p>Understanding the production of non-volatile particulate matter (nvPM), which is composed primarily of soot, is critical not only for reducing emissions but also for improving engine performance. While there has been significant prior work studying the fundamentals of soot formation, there is significantly less work that investigates soot formation with realistic aeroengine geometries, injectors, and fuels in high pressure conditions. In this work, soot production in a three-sector rich-quench-lean (RQL) aeroengine combustor is studied with Jet A fuel. Global equivalence ratios ranging of 0.10 to 0.20 and pressures ranging from 2.7 to 6.9 bar absolute (40 to 100 psia) are tested. In order to characterize <em>in-situ</em> soot production near the fuel injectors, two-dimensional laser-induced incandescence is utilized to estimate single-shot and average soot volume fractions. Time-resolved laser-induced incandescence is then used to create single camera and single laser-shot incandescence decay time images in order to infer how soot particle sizes evolve. Results show a significant increase in soot production at higher global equivalence ratios and higher pressures. Incandescence decay times, however, do not change significantly over the same range of conditions. These measurements can not only help understand soot distributions in practical RQL systems but also help improve future aeroengine combustor designs.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"18 ","pages":"Article 100269"},"PeriodicalIF":0.0,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000244/pdfft?md5=0e34fbc5fe8953025edeaeb834402357&pid=1-s2.0-S2666352X24000244-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140879873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Flame morphology and laminar flame assessments affected by flames interaction using multi-ignition sources of NH3/H2-air flames","authors":"Ahmed Yasiry ,&nbsp;Jinhua Wang ,&nbsp;Hongchao Dai ,&nbsp;Xiao Cai ,&nbsp;Ahmed A.A. Abdulraheem ,&nbsp;Saba Y. Ahmed ,&nbsp;Haroun A.K. Shahad ,&nbsp;Zuohua Huang","doi":"10.1016/j.jaecs.2024.100267","DOIUrl":"10.1016/j.jaecs.2024.100267","url":null,"abstract":"<div><p>A detailed assessment of flame–flame interaction and laminar flame evolution using multi-ignition sources is experimentally studied. To understand the flame interaction, the centrally ignited flame is measured and calculated for comparison with multi-ignition sources hydrogen–ammonia/flame. The location of the external ignition source, the delay time, the hydrogen blending, and the mixture equivalence ratio at an initial pressure of 0.1 MPa affect the propagation and morphology of the flame. It can be observed that the advancement of the pressure wave of the external flame causes deformation to the central flame front; This deformation occurs even before the interaction of the flames. The deformation can be decomposed into horizontal deformation, which decelerates the flame front as a result of the drag or accelerates due to the thrust of the flow field on the flame front. At the same time, vertical deformation is influenced by drag and thrust-lift forces. Therefore, the equivalent flame decelerates with time. This effect gives a nonsymmetric shape for expanding flame, and the shape changes from spherical to ellipsoidal, then a triaxial quasi-ellipsoid flame (scalene). The equivalent flame speed and laminar burning velocity are maximized near stoichiometry for all delay times and locations of the ignition source. As the delay time of the stoichiometric hydrogen ammonia/air increases, the equivalent laminar flame speed and laminar burning velocity monotonously decrease, as well as the time and location of the interaction. The equivalent flame speed and laminar burning velocity for ignition sources 1 and 2 decreases with delay time, and this becomes evident on the rich side. While employing a third ignition source increases with delay time since the drag force get eliminated from the horizontal axis. Furthermore, the hydrogen blending effect enhances and highlights these tendencies.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"18 ","pages":"Article 100267"},"PeriodicalIF":0.0,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000220/pdfft?md5=7a4eeb3fadeaa71449bd0efb65745160&pid=1-s2.0-S2666352X24000220-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140765315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-pressure gallium seeder for atomic fluorescence measurements","authors":"Thibault F. Guiberti ,&nbsp;Matteo Pesarini ,&nbsp;Roman Zamchii ,&nbsp;Sonu Kumar ,&nbsp;Wanxia Zhao ,&nbsp;Zeyad T. Alwahabi ,&nbsp;Bassam B. Dally","doi":"10.1016/j.jaecs.2024.100268","DOIUrl":"10.1016/j.jaecs.2024.100268","url":null,"abstract":"<div><p>This work presents the design and testing of a seeder based on laser ablation capable of introducing gallium particles into a gaseous flow at elevated pressures typical of that found in practical combustion devices. The ability to seed such a flow with gallium particles is required to apply Ga-TLAF, a spatially and temporally resolved thermometry imaging technique well suited to harsh combustion environments. The design criteria for this gallium particle seeder are first listed and all the necessary details required to understand and replicate it are then provided. Next, the efficiency of gallium ablation is verified as a function of the ablation laser's fluence and repetition rate and of the pressure using gallium laser induced fluorescence and laser scattering measurements at ∼403 nm. For the conventional 355-nm nanosecond, Nd:YAG laser used for ablation in this study, data show that the quantity of gallium seeded into the flow can be conveniently modulated by varying the fluence of the ablation laser and/or its repetition rate. Data also show that the efficiency of ablation is marginally better for solid gallium than for liquid gallium, but that ablation of liquid gallium should be preferred to avoid a loss of ablation efficiency after some time. The temperature of the liquid gallium feedstock is found to be unimportant. SEM, EDX, and SPMS analyses show that laser ablation yields pure gallium particles with a characteristic size ranging at least from 50 nm to 10 μm and that the size distribution is insensitive to the pressure and to the ablation laser's fluence. Also important for future applications of Ga-TLAF in high-pressure flames, data show that the gallium LIF intensity recorded at room temperature or in the hot products of a flame is not significantly affected by pressure.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"18 ","pages":"Article 100268"},"PeriodicalIF":0.0,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000232/pdfft?md5=cb0d97f3bcd5f73703ad7f131ff4c397&pid=1-s2.0-S2666352X24000232-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140776083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonlinear response of conical flame to dual-frequency excitation","authors":"Jianyi Zheng ,&nbsp;Lei Li ,&nbsp;Guoqing Wang ,&nbsp;Xi Xia ,&nbsp;Liangliang Xu ,&nbsp;Fei Qi","doi":"10.1016/j.jaecs.2024.100266","DOIUrl":"https://doi.org/10.1016/j.jaecs.2024.100266","url":null,"abstract":"<div><p>This work investigates the nonlinear response of a conical premixed flame to dual-frequency excitation through experiments and <em>G</em>-equation analysis. In addition to the responses at excitation frequencies, <span><math><msub><mi>f</mi><mn>1</mn></msub></math></span> and <span><math><msub><mi>f</mi><mn>2</mn></msub></math></span>, a notable flame response can also be identified at the difference frequency, <span><math><msub><mi>f</mi><mi>d</mi></msub></math></span>. The <span><math><msub><mi>f</mi><mi>d</mi></msub></math></span> response is particularly significant in the high-frequency regime, characterized by multiple wavelengths of both <span><math><msub><mi>f</mi><mn>1</mn></msub></math></span> and <span><math><msub><mi>f</mi><mn>2</mn></msub></math></span> on the flame front. This distinct behavior of difference-frequency response can be attributed to the spatial superposition of the intensified flame fluctuation waves at the two forcing frequencies. As the excitation enhances at either <span><math><msub><mi>f</mi><mn>1</mn></msub></math></span> or <span><math><msub><mi>f</mi><mn>2</mn></msub></math></span>, the nonlinear effect suppresses the responses of the upper-part flame at both <span><math><msub><mi>f</mi><mn>1</mn></msub></math></span> and <span><math><msub><mi>f</mi><mn>2</mn></msub></math></span> while promoting the bulk flame response at <span><math><msub><mi>f</mi><mi>d</mi></msub></math></span>. Based on a third-order expansion of the <em>G</em>-equation, it is shown that the nonlinear flame dynamics necessarily generate the observed interaction component when the flame is perturbed by dual-frequency excitations. The present results emphasize the importance of nonlinear flame dynamics in inducing flame responses at interaction frequencies, offering insights into thermoacoustic oscillations of multiple frequencies.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"18 ","pages":"Article 100266"},"PeriodicalIF":0.0,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000219/pdfft?md5=e2db6200132c998eef9b79f76bd339ce&pid=1-s2.0-S2666352X24000219-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140637919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impulse generated from detonation waves in non-premixed and partially premixed reactants","authors":"K. Mikoshiba,&nbsp;S.V. Sardeshmukh,&nbsp;Stephen D. Heister","doi":"10.1016/j.jaecs.2024.100264","DOIUrl":"https://doi.org/10.1016/j.jaecs.2024.100264","url":null,"abstract":"<div><p>Rotating detonation engines (RDEs) are the subject of research in the combustion community due to the prospects of enhanced thermal efficiency and power density when compared to current deflagrative-based aerospace combustors. Many current simulations presume premixed reactants and therefore miss the important characteristics of transient mixing, wave-induced mixing, and injector design/spacing that are known to play a pivotal role in the system performance. Very ambitious large eddy simulations are being conducted, but necessarily on a limited number of realistic and complex cases, thus limiting their utility in deriving fundamental understanding. For these reasons, a two dimensional parametric study was conducted to assess propagation of a detonation across an idealized array of mixing/injection sites, parametrically characterized by the width and axial mixing profile.</p><p>Under such non-premixed conditions, discrete energy release and interdependence are observed. The discrete energy release sites frequently create pressures that exceed idealized Chapman-Jouguet (CJ) predictions based on perfect and uniform mixtures. The local higher pressure is shown to be caused by delayed heat release behind the shock, near constant pressure combustion, and additional compression due to the non-uniformities present. The resulting compression and the near constant pressure combustion are accompanied by time scale separation of exothermic and endothermic reactions due to the mixing efficiencies in the non/poorly-premixed cases. In contrast, the better mixed cases show that the detonation wave is sustained but unburnt fuel and oxidizer exist behind the main combustion wave and impulse performance suffers. Results show that for the conditions modeled there exists an optimal injector spacing to maximize the impulse produced and that discrete injection impulses can exceed that of the premixed systems. These somewhat counter-intuitive results imply that the detailed mixing evolution, provoked by the passage of the wave can lead to an extended heat release zone that elevates the pressure over a longer distance along the wavefront. These revelations provide potential for optimizing injector configurations for real non-premixed systems in order to exploit these physics.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"18 ","pages":"Article 100264"},"PeriodicalIF":0.0,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000190/pdfft?md5=d9d17505aedf8834e24b87b1cd4180b6&pid=1-s2.0-S2666352X24000190-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140632924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A comparative pyrolysis study of tetraethoxysilane and tetraethoxymethane: Insight into congener substitution effects on pyrolysis chemistry of siloxane flame synthesis precursors","authors":"Qilong Fang ,&nbsp;Jun Fang ,&nbsp;Tianyou Lian ,&nbsp;Long Zhao ,&nbsp;Wei Li ,&nbsp;Yuyang Li","doi":"10.1016/j.jaecs.2024.100265","DOIUrl":"https://doi.org/10.1016/j.jaecs.2024.100265","url":null,"abstract":"<div><p>The pyrolysis of siloxane precursors, such as tetraethoxysilane (TEOS), is commonly employed in the flame synthesis and chemical vapor deposition of silica nanoparticles. In this work, the flow reactor pyrolysis of TEOS is studied using gas chromatography (GC) and synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS), and the congener substitution effects from the central C atom to the central Si atom are investigated through comparison with its hydrocarbon counterpart tetraethoxymethane (TEOM). Pyrolysis models of TEOS and TEOM are constructed and validated against the measured results. Modeling analysis, including rate of production analysis and sensitivity analysis, provides insights into chemistry in fuel consumption and product formation. In contrast, the observations of silicon-containing products in SVUV-PIMS experiments provide evidence for crucial decomposition pathways of TEOS. It is observed that TEOS exhibits significantly higher stability than TEOM under pyrolysis conditions. The most abundant products in the pyrolysis of TEOS and TEOM are ethylene and ethanol, and TEOS produces more hydrocarbon products than TEOM. The lower pyrolysis reactivity of TEOS is attributed to the slower unimolecular decomposition reaction which dominates the decomposition of TEOS than TEOM. This can be explained by the hindrance of the extremely strong Si-O bond resulting from the significantly different electronegativity between Si and O. The higher initial decomposition temperature of TEOS enhances the contribution of other decomposition channels, such as C-C bond dissociation and H-abstraction reactions, in TEOS consumption. This leads to the abundant formation of hydrocarbon productions such as methane, ethane, and acetaldehyde. As the main pyrolysis product, the ethanol produced by TEOM pyrolysis is four times that of TEOS due to the congener substitution effects. The ethanol formation pathway in TEOS pyrolysis is different from that in TEOM pyrolysis, which is mainly formed via a newly proposed multi-step mechanism, resulting in a lower yield in TEOS pyrolysis.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"18 ","pages":"Article 100265"},"PeriodicalIF":0.0,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000207/pdfft?md5=e4037a6028ea394f4bba57577f30b941&pid=1-s2.0-S2666352X24000207-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140545871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}