Applications in Energy and Combustion Science最新文献

{"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}

{"title":"Iron oxide nanoparticle synthesis: Simulation-based comparison of laboratory- and pilot plant-scale spray-flame synthesis","authors":"Sebastian Klukas ,&nbsp;Marcus Giglmaier ,&nbsp;Martin Underberg ,&nbsp;Sophie M. Schnurre ,&nbsp;Markus M. Prenting ,&nbsp;Torsten Endres ,&nbsp;Hartmut Wiggers ,&nbsp;Christof Schulz ,&nbsp;Moritz Sieber ,&nbsp;Sebastian Schimek ,&nbsp;Christian O. Paschereit ,&nbsp;Nikolaus A. Adams","doi":"10.1016/j.jaecs.2024.100263","DOIUrl":"10.1016/j.jaecs.2024.100263","url":null,"abstract":"<div><p>This study analyzes burner scale-dependent effects for iron-oxide nanoparticles synthesis in spray flames through a combined experimental and numerical approach. A laboratory- and a pilot plant-scale synthesis facility generate iron oxide nanoparticles from iron nitrate dissolved in ethanol/2-ethylhexanoic acid solvents on the 0.5 and 15 g/h scale, respectively. Phase Doppler measurements supply initial conditions for spray development in the numerical approach, while <em>in situ</em> OH* chemiluminescence and multi-line nitric oxide laser-induced fluorescence (NO-LIF) thermometry provide experimental data for comparison with simulation results of the pilot plant burner. <em>Ex situ</em> particle sizing by gas adsorption according to Brunauer-Emmet-Teller (BET) and transmission electron microscopy (TEM), along with phase composition determination via X-ray diffraction (XRD), are used to compare products of both burners and the corresponding simulations. The numerical approach employs a Reynolds-averaged Eulerian–Lagrangian description of the flow in combination with a flamelet/progress variable (FPV) combustion and monodisperse particle model to reflect spray-flame synthesis. Despite similar chemiluminescence between experiment and simulation, more significant discrepancies are observed in NO-LIF thermometry and particle sizing. Nanoparticle formation and growth at both burner scales is investigated using the numerical method. Special attention is directed to the high-temperature particle residence time (HTPRT). Notably, the average temperature–time profiles particles experience are almost identical in the burners, although their geometric scales and designs differ substantially. Simulation results show that while the primary particle diameter remains mostly consistent, the pilot-scale burner produces larger particle agglomerates than the laboratory burner. The difference is attributed to an increased particle number concentration during the initial formation of soft agglomerates. The findings demonstrate that, despite retaining a similar HTPRT, the overall flow conditions and liquid spray dispersion, which impact the distribution of the particle number concentration, influence the final agglomerate size.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"18 ","pages":"Article 100263"},"PeriodicalIF":0.0,"publicationDate":"2024-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000189/pdfft?md5=d0ee566b7899e4063d0e19910649271e&pid=1-s2.0-S2666352X24000189-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140792442","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":"Experimental investigation of the effects of inlet high-swirl air preheating and dilution on kerosene flame","authors":"A. Mardani,&nbsp;S. Arazi Kalat,&nbsp;A. Azimi","doi":"10.1016/j.jaecs.2024.100262","DOIUrl":"https://doi.org/10.1016/j.jaecs.2024.100262","url":null,"abstract":"<div><p>This study investigated the effects of co-flow air swirling on the combustion of Kerosene, as relatively heavy fuel, under preheated and diluted air conditions. Various factors affecting the flame structure, such as preheating temperature, dilution, swirl number, and airflow rate were studied using the upgraded MILD (Moderate or Intense Low-Oxygen Dilution) combustion tester of Sharif University of Technology (SMSTR). This tester, which is symmetrically axial, provides co-flow air with the desired temperature, swirl number, and dilution for a liquid fuel spray burner. The flame characteristics was investigated through direct photography and chemiluminescence. The results show that the stability range significantly increases with the air swirling, while the flame length decreases. Enhancement of combustion quality and more complete combustion of fuel were observed with preheating. Preheating resulted in geometric changes in the appearance of the flame, specially reducing flame lift-off and the front view area in high airflow. A decrease in the air oxygen content causes a general change in the structure of the flame, resulting in a shorter and more lifted one compared to non-diluted condition. The chemiluminescence images of the flame also revealed weaker and more uniform emission pattern with the inlet high-swirl air preheating and dilution. By utilizing around 15 % oxygen content dilution, preheating at around 656 K, and a swirl number of 0.8, the combustion zone exhibited similarities to the MILD combustion mode, suggesting the achievement of MILD combustion. The high swirl concept allowed higher dilution limits (about 12 %) and reduced preheating requirements (approximately 11 %) in achieving the MILD combustion regime compared to the previous study conducted without swirl conditions. In contrast to the non-swirl mode flame, the flame in this study transitioned completely to a MILD-like condition.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"18 ","pages":"Article 100262"},"PeriodicalIF":0.0,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000177/pdfft?md5=decfcf625d9273fe9ef61b8503e8b767&pid=1-s2.0-S2666352X24000177-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140548610","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":"Steady laminar stagnation flow NH3-H2-air flame at a plane wall: Flame extinction limit and its influence on the thermo-mechanical stress and corrosive behavior of wall materials","authors":"Chunkan Yu ,&nbsp;Surabhi Srikanth ,&nbsp;Thomas Böhlke ,&nbsp;Bronislava Gorr ,&nbsp;Ulrich Maas","doi":"10.1016/j.jaecs.2024.100261","DOIUrl":"https://doi.org/10.1016/j.jaecs.2024.100261","url":null,"abstract":"<div><p>The steady laminar stagnation flow flame of NH<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>-H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>-air gas mixture stabilized at a plane wall is numerically investigated. Its interaction with the wall with the consideration of heat loss is the focus of this work. The numerical study of the combustion system is performed by using the full chemical mechanism and detailed transport model including the differential diffusion and Soret effect. The simulation of the solid mechanics is based on the theory of isotropic linear thermo-elasticity. With the numerical simulation, it will be discussed how the wall material would change the flame stability in terms of extinction limit, and how the combustion system such as mixture composition, flame strain rate, and pressure would vary the thermo-mechanical stresses in the solid wall and the corrosive behavior at the surface of the wall.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"18 ","pages":"Article 100261"},"PeriodicalIF":0.0,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000165/pdfft?md5=8281e8ecb0e665db6654c37457f71c22&pid=1-s2.0-S2666352X24000165-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140290289","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":"Characterization of a 5-nozzle array using premix/micromix injection for hydrogen","authors":"Antoine Durocher ,&nbsp;Luming Fan ,&nbsp;Marc Füri ,&nbsp;Gilles Bourque ,&nbsp;Julien Sirois ,&nbsp;David May ,&nbsp;Jeffrey M. Bergthorson ,&nbsp;Sean Yun ,&nbsp;Patrizio Vena","doi":"10.1016/j.jaecs.2024.100260","DOIUrl":"10.1016/j.jaecs.2024.100260","url":null,"abstract":"<div><p>Hydrogen is one of the most promising fuels to decarbonize energy systems since it has a high specific energy, a carbon-free combustion process, and may be produced sustainably through electrolysis. Direct fuel drop-in replacement cannot be done in traditional lean, premixed combustion burners because of the high reactivity of the hydrogen-air mixture and its inherently unstable nature that might lead to flashback and hardware failure. Consequently, new injection strategies and burner geometries are investigated to mitigate these risks. Here we present hydrogen capabilities of a premix/micromix injector that relies on a two-staged fuel injection strategy to offer wide fuel flexible capability (methane to hydrogen) within a single design. Five injectors are placed in a cross-shaped array to simulate a sector found in multi-element combustion systems. Stability and combustion dynamics maps are obtained for the array and OH planar laser-induced fluorescence (PLIF) provides additional insight into the combustion process of these novel burners when placed in an array. The use of micromixing is shown to drastically improve the acoustics of this geometry and expand the flashback limits compared to the fully premixed configuration. Significant variability in flashback limits are observed for different additively-manufactured injector configurations. Phase-averaged OH-PLIF measurements, obtained by registering the acquisition with the acoustics module, and the 3D reconstruction of a partially-premixed flame highlight the complexity of the stabilization mechanisms for these highly three-dimensional, non-axisymmetric flames that may be subjected to large thermoacoustics. This first investigation into premix/micromix clustered injectors demonstrates the importance of better understanding the impact of flame–flame interaction in multi-element combustion systems with micromixed, or partially-premixed, combustion.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"18 ","pages":"Article 100260"},"PeriodicalIF":0.0,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000153/pdfft?md5=f3ff9a7796690401497bc50b33a458cd&pid=1-s2.0-S2666352X24000153-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140272036","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":"Future of hydrogen in the U.S. energy sector: MARKAL modeling results","authors":"Nadejda Victor ,&nbsp;Christopher Nichols","doi":"10.1016/j.jaecs.2024.100259","DOIUrl":"https://doi.org/10.1016/j.jaecs.2024.100259","url":null,"abstract":"<div><p>Hydrogen is an attractive energy carrier which could play a role in decarbonizing process heat, power or transport applications. Though the U.S. already produces about 10 million metric tons of H2 (over 1 quadrillion BTUs or 1 % of the U.S. primary energy consumption), production technologies primarily use fossil fuels that release CO2, and the deployment of other, cleaner H2 production technologies is still in the very early stages in the U.S. This study explores (1) the level of current U.S. hydrogen production and demand, (2) the importance of hydrogen to accelerate a net-zero CO2 future, and (3) the challenges that must be overcome to make hydrogen an important part of the U.S. energy system. The study discusses four scenarios and hydrogen production has been shown to increase in the future, but this growth is not enough to establish a hydrogen economy. In this study, the characteristics of hydrogen technologies and their deployments in the long-term future are investigated using energy system model MARKAL. The effects of strong carbon constraints do not cause higher hydrogen demand but show a decrease in comparison to the business-as-usual scenario. Further, according to our modeling results, hydrogen grows only as a fuel for hard-to-decarbonize heavy-duty vehicles and is less competitive than other decarbonization solutions in the U.S. Without improvements in reducing the cost of electrolysis and increasing the performance of near-zero carbon technologies for hydrogen production, hydrogen will remain a niche player in the U.S. energy system in the long-term future. This article provides the reader with a comprehensive understanding of the role of hydrogen in the U.S. energy system, thereby explaining the long-term future projections.</p></div>","PeriodicalId":100104,"journal":{"name":"Applications in Energy and Combustion Science","volume":"18 ","pages":"Article 100259"},"PeriodicalIF":0.0,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666352X24000141/pdfft?md5=c2c85713886cc78f1f8c5db4d30a23b8&pid=1-s2.0-S2666352X24000141-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140134121","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}