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Artigos de revistas sobre o tema "Lean hydrogen"

Autor: Grafiati

Publicado: 29 de março de 2025

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1

Pan, Shiyi, Jinhua Wang, Bin Liang, Hao Duan e Zuohua Huang. "Experimental Study on the Effects of Hydrogen Injection Strategy on the Combustion and Emissions of a Hydrogen/Gasoline Dual Fuel SI Engine under Lean Burn Condition". Applied Sciences 12, n.º 20 (19 de outubro de 2022): 10549. http://dx.doi.org/10.3390/app122010549.

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Hydrogen addition can improve the performance and extend the lean burn limit of gasoline engines. Different hydrogen injection strategies lead to different types of hydrogen mixture distribution (HMD), which affects the engine performance. Therefore, the present study experimentally investigated the effects of hydrogen injection strategy on the combustion and emissions of a hydrogen/gasoline dual-fuel port-injection engine under lean-burn conditions. Four different hydrogen injection strategies were explored: hydrogen direct injection (HDI), forming a stratified hydrogen mixture distribution (SHMD); hydrogen intake port injection, forming a premixed hydrogen mixture distribution (PHMD); split hydrogen direct injection (SHDI), forming a partially premixed hydrogen mixture distribution (PPHMD); and no hydrogen addition (NHMD). The results showed that 20% hydrogen addition could extend the lean burn limit from 1.5 to 2.8. With the increase in the excess air ratio, the optimum HMD changed from PPHMD to SHMD. The maximum brake thermal efficiency was obtained with an excess air ratio of 1.5 with PPHMD. The coefficient of variation (COV) with NHMD was higher than that with hydrogen addition, since the hydrogen enhanced the stability of ignition and combustion. The engine presented the lowest emissions with PHMD. There were almost no carbon monoxide (CO) and nitrogen oxides (NOx) emissions when the excess air ratio was, respectively, more than 1.4 and 2.0.

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SWAIN, M., P. FILOSO e M. SWAIN. "Ignition of lean hydrogen–air mixtures". International Journal of Hydrogen Energy 30, n.º 13-14 (outubro de 2005): 1447–55. http://dx.doi.org/10.1016/j.ijhydene.2004.10.017.

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3

Bo-wei, JIAO, YU Nan-jia e ZHOU Chuang. "Parameter optimization and simulation of lean-burn gas generator". Journal of Physics: Conference Series 2235, n.º 1 (1 de maio de 2022): 012080. http://dx.doi.org/10.1088/1742-6596/2235/1/012080.

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Abstract The pre-cooling engine cools the incoming air through a pre-cooler and then makes it enter the subsequent components to work. This type of engine is one of the most important development directions in the combined power scheme. In order to accurately control the lean-burn gas temperature and oxygen concentration under different incoming flow conditions, and adjust it through the nitrogen-to-hydrogen ratio (GNGH) and oxygen-to-hydrogen ratio (GOGH). The oxygen concentration and temperature were obtained by thermal calculation and the optimal nitrogen-hydrogen ratio and oxygen-hydrogen ratio were optimized by genetic algorithm. Finally, the sensitivity analysis of the influence of nitrogen-hydrogen ratio and oxygen-hydrogen ratio on temperature and oxygen concentration was performed near the optimal point. According to the research, when α (weight coefficient) is determined, as the height increases, GNGH and GOGH decreases, and the amount of hydrogen required increases. When α > 1, the temperature term plays a major role in the optimization result. When α < 0.01, the oxygen concentration term plays a major role in the optimization result. When 0.01 < α < 1, the temperature term and oxygen concentration term are considered to have an effect on the optimization result at the same time. For the sensitivity analysis of the nitrogen-hydrogen ratio, oxygen-hydrogen ratio, temperature and oxygen concentration under different working conditions, accurate numerical results have also been obtained.

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YAMAMOTO, Kazuhiro, Masayuki MARUYAMA e Yoshiaki ONUMA. "Effects of Hydrogen Addition on Lean Combustion." Transactions of the Japan Society of Mechanical Engineers Series B 64, n.º 622 (1998): 1919–24. http://dx.doi.org/10.1299/kikaib.64.1919.

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Schefer, R. "Hydrogen enrichment for improved lean flame stability". International Journal of Hydrogen Energy 28, n.º 10 (outubro de 2003): 1131–41. http://dx.doi.org/10.1016/s0360-3199(02)00199-4.

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Krivosheyev, Pavel, Yuliya Kisel, Аlexander Skilandz, Kirill Sevrouk, Oleg Penyazkov e Anatoly Tereza. "Ignition delay of lean hydrogen-air mixtures". International Journal of Hydrogen Energy 66 (maio de 2024): 81–89. http://dx.doi.org/10.1016/j.ijhydene.2024.03.363.

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Leyko, Jacek, Kamil Słobiński, Jarosław Jaworski, Grzegorz Mitukiewicz, Wissam Bou Nader e Damian Batory. "Study on SI Engine Operation Stability at Lean Condition—The Effect of a Small Amount of Hydrogen Addition". Energies 16, n.º 18 (17 de setembro de 2023): 6659. http://dx.doi.org/10.3390/en16186659.

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The lean-burn mode is a solution that reduces the fuel consumption of spark-ignition internal combustion engines and keeps the low exhaust emission, but the stability of the lean-burn combustion process, especially at low loads, needs to be addressed. Enhancing gasoline with hybrid hydrogen oxygen (HHO) gas—a mixture of hydrogen and oxygen gases—is proposed to improve combustion of the lean-gasoline mixture. A three-cylinder, spark-ignition, naturally aspirated, MPI engine with HHO gas produced with an alkaline water electrolyzer and introduced as a gasoline enhancement was tested. The amount of hydrogen added to the lean-gasoline mixture (λ = 1.4) was in the range from 0.15 to 1.5%, and the results were compared to the stoichiometric (λ = 1) and pure lean mode (λ = 1.4) gasoline operation. The other authors’ results show that a minimum 3% of the mass fraction of hydrogen is necessary to affect the gasoline combustion process. This paper proved that even a small hydrogen enhancement of gasoline in the amount of 0.3% of the mass fraction improves the combustion stability.

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Griebel, P., E. Boschek e P. Jansohn. "Lean Blowout Limits and NOx Emissions of Turbulent, Lean Premixed, Hydrogen-Enriched Methane/Air Flames at High Pressure". Journal of Engineering for Gas Turbines and Power 129, n.º 2 (15 de agosto de 2006): 404–10. http://dx.doi.org/10.1115/1.2436568.

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Flame stability is a crucial issue in low NOx combustion systems operating at extremely lean conditions. Hydrogen enrichment seems to be a promising option to extend lean blowout limits (LBO) of natural gas combustion. This experimental study addresses flame stability enhancement and NOx reduction in turbulent, high-pressure, lean premixed methane/air flames in a generic combustor capable of a wide range of operating conditions. Lean blowout limits and NOx emissions are presented for pressures up to 14bar, bulk velocities in the range of 32–80m∕s, two different preheating temperatures (673K, 773K), and a range of fuel mixtures from pure methane to 20% H2∕80%CH4 by volume. The influence of turbulence on LBO limits is also discussed. In addition to the investigation of perfectly premixed H2-enriched flames, LBO and NOx are also discussed for hydrogen piloting. Experiments have revealed that a mixture of 20% hydrogen and 80% methane, by volume, can typically extend the lean blowout limit by ∼10% compared to pure methane. The flame temperature at LBO is ∼60K lower resulting in the reduction of NOx concentration by ≈35%(0.5→0.3ppm∕15%O2).

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Meyers, D. P., e J. T. Kubesh. "The Hybrid Rich-Burn/Lean-Burn Engine". Journal of Engineering for Gas Turbines and Power 119, n.º 1 (1 de janeiro de 1997): 243–49. http://dx.doi.org/10.1115/1.2815555.

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This paper describes a new low-emissions engine concept called the hybrid rich-burn/lean-burn (HRBLB) engine. In this concept a portion of the cylinders of a multicylinder engine are fueled with a very rich natural gas-air mixture. The remaining cylinders are operated with a lean mixture of natural gas and air and supplemented with the rich combustion exhaust. The goal of this unique concept is the production of extremely low NOx (e.g., 5 ppm when corrected to 15 percent exhaust oxygen content). This is accomplished by operating outside the combustion limits where NOx is produced. In rich combustion an abundance of hydrogen and carbon monoxide is produced. Catalyst treatment of the rich exhaust can be employed to increase the hydrogen concentration and decrease the carbon monoxide concentration simultaneously. The hydrogen-enriched exhaust is used to supplement the lean mixture cylinders to extend the lean limit of combustion, and thus produces ultralow levels of NOx. Results to date have shown NOx levels as low as 8 ppm at 15 percent oxygen can be achieved with good combustion stability and thermal efficiency.

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10

Popelka, Josef. "Design of System Hydrogen Engine Supercharging". Advanced Materials Research 1016 (agosto de 2014): 607–11. http://dx.doi.org/10.4028/www.scientific.net/amr.1016.607.

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In this paper I am dealing with a general analysis of problems burning of lean hydrogen mixtures in combustion engines. During burning of very lean mixtures burning procedure is over lasted with characteristic features. They need to be removed or reduced. One of these features is low power of engines operating by lean mixtures, which can be partially removed with the help of supercharging such engines. In the second part of the paper I am dealing with a design of supercharging system for a three-cylinder engine with volume 1,2 dm3.

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Leite, Caio Ramalho, Pierre Brequigny, Jacques Borée e Fabrice Foucher. "Comparative Analysis Of Cycle-To-Cycle Variabilities And Combustion Development In An Optical Spark-Ignition Engine Fueled By Pure Hydrogen And Propane: Insights From Chemiluminescence and PI". Proceedings of the International Symposium on the Application of Laser and Imaging Techniques to Fluid Mechanics 21 (8 de julho de 2024): 1–18. http://dx.doi.org/10.55037/lxlaser.21st.122.

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Hydrogen, derived from renewable sources and devoid of carbon emissions, is a pivotal energy carrier for the future. Representing a viable substitute for fossil fuels in internal combustion engines (ICEs), contemporary studies advocate using very-lean and ultra-lean hydrogen-air mixtures, with a fuel-air equivalence ratio below 0.5, as a potent strategy to reduce NOx emissions in hydrogen-fueled ICEs. An experimental setup with an optical spark-ignition engine was devised to investigate the primary factors influencing cycle-to-cycle variations in H2ICEs by optimizing mixture homogeneity and focusing the study on flame interaction with in-cylinder aerodynamics. Simultaneous in-cylinder pressure, chemiluminescence, and PIV analyses were performed to characterize and compare the behaviors of ultra-lean hydrogen-air and propane-air flames, assessing flame development and cyclic variation features. Results indicate that the flame development of hydrogen and propane is significantly different. Propane exhibited increased in-cylinder pressure trace variability at lean and rich flammability limits with a high flame development difference between fast and slow cycles. In contrast, hydrogen-air mixtures under various equivalence ratios (from very-lean to ultra-lean) presented much more stable in-cylinder pressures. Furthermore, fast propane flames were mainly advected to the cylinder's symmetrical axes, while fast hydrogen flames started further away from the spark plug. Horizontal and vertical PIV measurements showed a single structure flow field over the studied conditions with mainly intensity variations over the measured cycles. Fast flames were associated with more intense tumble motion. The differences between fast and slow flames for hydrogen are attributed to the early flame development. However, after initial differences in flame development over several crank angles, there are similarities in all cycles, suggesting that the low variability in in-cylinder pressures is mostly due to the robustness of hydrogen flame ignition and its independence from in-cylinder flow small variations at the early development phase.

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Filomeno, Giovanni, Tommaso Capurso, Marco Torresi e Giuseppe Pascazio. "Numerical study of the lean premixed PRECCINSTA burner with hydrogen enrichment". E3S Web of Conferences 312 (2021): 11014. http://dx.doi.org/10.1051/e3sconf/202131211014.

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Hydrogen combustion is one of the most promising solution to achieve a global decarbonization in power production and transports. Pure hydrogen combustion is far from becoming a standard but, during the energy transition, hydrogen co-firing can be a feasible and economically attractive shortterm measure. The use of hydrogen blending gives rise to several issues related to flashback, NOx emissions and thermo-acoustic instabilities. To improve the understanding of the effect of hydrogen enrichment, herein a numerical analysis of lean premixed hydrogen enriched flames is performed by means of 3D unsteady CFD simulations. The numerical model has been assessed against experimental results for both cold and reacting flows in terms of velocity profile (average) and flame shape (mean OH* radical fields). The burner under investigation is the swirl stabilized PRECCINSTA studied at the Deutsches Zentrum für Luft-und Raumfahrt (DLR). The DLR’s researchers have shown the effect of hydrogen addition on the flame topology and combustion instabilities at various operating conditions in terms of thermal power, equivalence ratio and H2 volume fraction. Simulations are in good accordance with experimental data both in terms of velocity and temperature profiles. The numerical model provides a qualitative estimation of the flame shape.

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13

Song, Wonsik, Francisco E. Hernández-Pérez e Hong G. Im. "Diffusive effects of hydrogen on pressurized lean turbulent hydrogen-air premixed flames". Combustion and Flame 246 (dezembro de 2022): 112423. http://dx.doi.org/10.1016/j.combustflame.2022.112423.

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WIERZBA, I. "Catalytic oxidation of lean homogeneous mixtures of hydrogen/hydrogen?methane in air". International Journal of Hydrogen Energy 29, n.º 12 (setembro de 2004): 1303–7. http://dx.doi.org/10.1016/j.ijhydene.2003.12.012.

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15

Mahjoub, Mustafa, Aleksandar Milivojevic, Vuk Adzic, Marija Zivkovic, Vasko Fotev e Miroljub Adzic. "Numerical analysis of lean premixed combustor fueled by propane-hydrogen mixture". Thermal Science 21, n.º 6 Part A (2017): 2599–608. http://dx.doi.org/10.2298/tsci160717131m.

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A numerical investigation of combustion of propane-hydrogen mixture in a swirl premixed micro gas turbine combustor is presented. The effects of hydrogen addition into propane on temperature distribution in the combustor, reaction rates of propane and hydrogen and NOx emissions for different equivalence ratios and swirl numbers are given. The propane-hydrogen mixture of 90/10% by volume was assumed. The numerical results and measurements of NOx emissions for pure propane are compared. Excellent agreements are found for all equivalence ratios and swirl numbers, except for the highest swirl number (1.13). It is found that the addition of hydrogen into propane increases NOx emission. On the other hand, the increase of swirl number and the decrease of equivalence ratio decrease the NOx emissions.

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16

Fernández-Tarrazo, E., A. L. Sánchez, A. Liñán e F. A. Williams. "The structure of lean hydrogen-air flame balls". Proceedings of the Combustion Institute 33, n.º 1 (2011): 1203–10. http://dx.doi.org/10.1016/j.proci.2010.05.086.

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17

Aspden, A. J., M. S. Day e J. B. Bell. "Turbulence-chemistry interaction in lean premixed hydrogen combustion". Proceedings of the Combustion Institute 35, n.º 2 (2015): 1321–29. http://dx.doi.org/10.1016/j.proci.2014.08.012.

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Treviño, C. "Catalytic ignition of very lean mixtures of hydrogen". International Journal of Hydrogen Energy 36, n.º 14 (julho de 2011): 8610–18. http://dx.doi.org/10.1016/j.ijhydene.2011.03.129.

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19

Gavrikov, Andrey I., Victor V. Golub, Anton Yu Mikushkin, Vyatcheslav A. Petukhov e Vladislav V. Volodin. "Lean hydrogen-air premixed flame with heat loss". International Journal of Hydrogen Energy 44, n.º 36 (julho de 2019): 20462–69. http://dx.doi.org/10.1016/j.ijhydene.2019.05.239.

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Tereza, A. M., G. L. Agafonov, E. K. Anderzhanov, A. S. Betev, S. P. Medvedev, S. V. Khomik e T. T. Cherepanova. "Structure of a Lean Laminar Hydrogen–Air Flame". Russian Journal of Physical Chemistry B 17, n.º 4 (agosto de 2023): 974–78. http://dx.doi.org/10.1134/s1990793123040309.

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21

Kahangamage, Udaya, Yi Chen, Chun Wah Leung e Tung Yan Ngai. "Experimental Study of Lean-burning Limits of Hydrogen-enriched LPG Intended for Domestic Use". Journal of Energy and Power Technology 4, n.º 2 (2 de janeiro de 2022): 1. http://dx.doi.org/10.21926/jept.2202016.

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The lean-burning limits of hydrogen-enriched Liquefied Petroleum Gas (LPG) have been studied using a Bunsen burner. The lean-burning limits under different conditions are important design considerations in developing gas-fired domestic appliances. In this study, the lean-burning limits of hydrogen-enriched LPG have been obtained across a wide range of Reynolds numbers (600 to 1800) and H2 volumetric fractions (0% to 25%). The results show that the lean-burning limit is increased, on average, by 4.0% to 7.2% for every 5% increment of H2 volumetric fraction under different Reynolds numbers. A numerical simulation carried out in CHEMKIN using the USC Mech II reaction mechanism, and the observation of flame characteristics show that the increase in lean-burning limit with increasing H2 content is due to the higher burning velocity of LPG-H2 mixtures compared with pure LPG. More fuel is required to offset the effect of increased burning velocity under the same Reynolds number, leading to an increase in the lean-burning limit. To facilitate the visualization of the variation of the lean-burning limit with increasing H2 volume fraction in the mixed fuel at different Reynolds numbers, a lean-burning limit map is developed based on correlations obtained. The results of this study provide reference values for the lean-burning performance of hydrogen-enriched LPG fuel for practical domestic use.

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Di Sarli, Valeria. "Stability and Emissions of a Lean Pre-Mixed Combustor with Rich Catalytic/Lean-burn Pilot". International Journal of Chemical Reactor Engineering 12, n.º 1 (1 de janeiro de 2014): 77–89. http://dx.doi.org/10.1515/ijcre-2013-0112.

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Abstract In this work, a reactor network model was developed to study homogeneous gas-phase methane combustion taking place under typical operating conditions of lean pre-mixed combustors piloted by rich catalytic/lean-burn (RCL) systems. In particular, the thermo-kinetic interaction between the pilot stream (i.e. the stream exiting the RCL stage) and the main feeding stream to the homogeneous reactor was investigated in terms of combustion stability and emissions. The homogeneous combustor was modeled as a perfectly stirred reactor (PSR). The pilot stream was mixed with the main feeding stream prior to entering the PSR. Numerical results have shown that the opportunity to stabilize combustion is strongly linked to the presence of hydrogen in the pilot stream. Combustion stability is highly sensitive to variations in fuel split between catalytic pilot and homogeneous reactor. The increase in pilot fuel split (and, thus, in the inlet hydrogen concentration to the PSR) enlarges the operating window of stable combustion (in terms of higher heat losses, lower preheat temperatures and lower residence times), while still achieving NOx and CO emissions lower than 9 ppm (at 15% O2). These results highlight the potential of the RCL technology as a valuable alternative to conventional diffusion flame-based pilots.

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23

Bauwens, C. R., J. Chao e S. B. Dorofeev. "Effect of hydrogen concentration on vented explosion overpressures from lean hydrogen–air deflagrations". International Journal of Hydrogen Energy 37, n.º 22 (novembro de 2012): 17599–605. http://dx.doi.org/10.1016/j.ijhydene.2012.04.053.

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Chaichan, Miqdam Tariq. "Characterization of Lean Misfire Limits of Mixture Alternative Gaseous Fuels Used for Spark Ignition Engines". Tikrit Journal of Engineering Sciences 19, n.º 1 (31 de março de 2012): 50–61. http://dx.doi.org/10.25130/tjes.19.1.06.

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Increasing on gaseous fuels as clean, economical and abundant fuels encourages the search for optimum conditions of gas-fueled internal combustion engines. This paper presents the experimental results on the lean operational limits of Recardo E6 engine using gasoline, LPG, NG and hydrogen as fuels. The first appearance of almost motoring cycle was used to define the engine lean limit after the fuel flow was reduced gradually. The effects of compression ratio, engine speed and spark timing on the engine operational limits are presented and discussed in detailed. Increasing compression ratio (CR) extend the lean limits, this appears obviously with hydrogen, which has a wide range of equivalence ratios, while for hydrocarbon fuel octane number affect gasoline, so it can' t work above CR=9:1, and for LPG it reaches CR=12:1, NG reaches CR=15:1 at lean limit operation. Movement from low speeds to medium speeds extended lean misfire limits, while moving from medium to high speeds contracted the lean misfiring limits. NOx, CO and UBHC concentrations increased with CR increase for all fuels, while CO2 concentrations reduced with this increment. NOx concentration increased for medium speeds and reduced for high speeds, but the resulted concentrations were inconcedrable for these lean limits. CO and CO2 increased with engine speed increase, while UBHC reduced with this increment. The hydrogen engine runs with zero CO, CO2 and UNHC concentrations, and altra low levels of NOx concentrations at studied lean misfire limits.

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Weber, Sebastian, Mauro Martin e Werner Theisen. "Development of Lean Alloyed Austenitic Stainless Steels with Reduced Tendency to Hydrogen Environment Embrittlement". Materials Science Forum 706-709 (janeiro de 2012): 1041–46. http://dx.doi.org/10.4028/www.scientific.net/msf.706-709.1041.

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Hydrogen gas is believed to play a more important role for energy supply in future instationary and mobile applications. In most cases, metallic materials are embrittled when hydrogen atoms are dissolved interstitially into their lattice. Concerning steels, in particular the ductility of ferritic grades is degraded in the presence of hydrogen. In contrast, austenitic steels usually show a lower tendency to hydrogen embrittlement. However, the so-called “metastable” austenitic steels are prone to hydrogen environmental embrittlement (HEE), too. Here, AISI 304 type austenitic steel was tensile tested in air at ambient pressure and in a 400 bar hydrogen gas atmosphere at room temperature. The screening of different alloys in the compositional range of the AISI 304 standard was performed with the ambition to optimize alloying for hydrogen applications. The results of the mechanical tests reveal the influence of the alloying elements Cr, Ni, Mn and Si on HEE. Besides nickel, a positive influence of silicon and chromium was found. Experimental results are supported by thermodynamic equilibrium calculations concerning austenite stability and stacking fault energy. All in all, the results of this work are useful for alloy design for hydrogen applications. A concept for a lean alloyed austenitic stainless steel is finally presented.

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Lee, Taesong, e Kyu Tae Kim. "Curvature Distribution of Lean-Premixed Mesoscale Multinozzle Hydrogen Flames". Journal of The Korean Society of Combustion 26, n.º 1 (31 de março de 2021): 14–21. http://dx.doi.org/10.15231/jksc.2021.26.1.014.

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YOSHIKAWA, Norihiko, Hiroyasu SAITOH e Tomoaki YOSHIDA. "Enhancement of Volumetric Ignition in Lean Hydrogen-Air Mixtures". Journal of the Visualization Society of Japan 27, Supplement2 (2007): 177–78. http://dx.doi.org/10.3154/jvs.27.supplement2_177.

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Bastiaans, Rob, e A. W. Vreman. "Numerical simulation of instabilities in lean premixed hydrogen combustion". International Journal of Numerical Methods for Heat & Fluid Flow 22, n.º 1 (6 de janeiro de 2012): 112–28. http://dx.doi.org/10.1108/09615531211188829.

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Khamedov, Ruslan, Mohammad Rafi Malik, Francisco E. Hernández-Pérez e Hong G. Im. "Propagation characteristics of lean turbulent premixed ammonia–hydrogen flames". Proceedings of the Combustion Institute 40, n.º 1-4 (2024): 105736. http://dx.doi.org/10.1016/j.proci.2024.105736.

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Sanchez Bahoque, Gabriela, e Jeroen van Oijen. "Flamelet generated manifolds for lean premixed turbulent hydrogen flames". Proceedings of the Combustion Institute 40, n.º 1-4 (2024): 105614. http://dx.doi.org/10.1016/j.proci.2024.105614.

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Iacoviello, Francesco, Vittorio Di Cocco, Costanzo Bellini e Luca Sorrentino. "Hydrogen embrittlement in a 2101 lean Duplex Stainless Steel". Procedia Structural Integrity 18 (2019): 391–98. http://dx.doi.org/10.1016/j.prostr.2019.08.180.

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Shudo, T. "NOx emission characteristics in rich–lean combustion of hydrogen". JSAE Review 23, n.º 1 (janeiro de 2002): 9–14. http://dx.doi.org/10.1016/s0389-4304(01)00163-1.

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Ren, J. Y., W. Qin, F. N. Egolfopoulos e T. T. Tsotsis. "Strain-rate effects on hydrogen-enhanced lean premixed combustion". Combustion and Flame 124, n.º 4 (março de 2001): 717–20. http://dx.doi.org/10.1016/s0010-2180(00)00205-4.

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Berger, Lukas, Konstantin Kleinheinz, Antonio Attili e Heinz Pitsch. "Characteristic patterns of thermodiffusively unstable premixed lean hydrogen flames". Proceedings of the Combustion Institute 37, n.º 2 (2019): 1879–86. http://dx.doi.org/10.1016/j.proci.2018.06.072.

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Seshadri, K., N. Peters e F. A. Williams. "Asymptotic analyses of stoichiometric and lean hydrogen-air flames". Combustion and Flame 96, n.º 4 (março de 1994): 407–27. http://dx.doi.org/10.1016/0010-2180(94)90108-2.

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KITAGAWA, T., H. KIDO, N. NAKAMURA e M. AISHIMA. "Flame inertia into lean region in stratified hydrogen mixture". International Journal of Hydrogen Energy 30, n.º 13-14 (outubro de 2005): 1457–64. http://dx.doi.org/10.1016/j.ijhydene.2004.11.002.

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Shahamiri, S. A., e I. Wierzba. "Simulation of catalytic oxidation of lean hydrogen–methane mixtures". International Journal of Hydrogen Energy 34, n.º 14 (julho de 2009): 5785–94. http://dx.doi.org/10.1016/j.ijhydene.2009.04.077.

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Fernández-Galisteo, D., A. L. Sánchez, A. Liñán e F. A. Williams. "One-step reduced kinetics for lean hydrogen–air deflagration". Combustion and Flame 156, n.º 5 (maio de 2009): 985–96. http://dx.doi.org/10.1016/j.combustflame.2008.10.009.

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39

Terezaa, A. M., G. L. Agafonova, E. K. Anderzhanov, A. S. Betev, S. P. Medvedev, V. N. Mikhalkin, S. V. Khomik e T. T. Cherepanova. "Effect of Impurities on Lean Laminar Hydrogen–air Flames". Химическая физика 42, n.º 12 (1 de dezembro de 2023): 48–53. http://dx.doi.org/10.31857/s0207401x23120130.

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Simulations of the effect of addition of H, O, OH, HO2, and H2O2 on the structure and propagationof laminar flames in lean (12 and 15%) hydrogen-air flames are performed at pressures of 1 and 6 bar. Itis found that impurities in concentrations of no more than 0.1% do not have any significant effect on laminarburning velocity. When initial temperature is increased to 400 K, the effect of impurities becomes evenweaker. Among the impurities under study, only the addition of OH reduces the laminar flame velocity. Theweak effect of the impurities is attributed to fast formation of intermediate products via reactions involving Oand H atoms without noticeable change in heat release rate. An increase in initial pressure to 6 bar does notchange the effect of impurities.

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40

Tereza, A. M., G. L. Agafonov, E. K. Anderzhanov, A. S. Betev, S. P. Medvedev, V. N. Mikhalkin, S. V. Khomik e T. T. Cherepanova. "Effect of Impurities on Lean Laminar Hydrogen–Air Flames". Russian Journal of Physical Chemistry B 17, n.º 6 (dezembro de 2023): 1294–99. http://dx.doi.org/10.1134/s1990793123060246.

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41

Shang, Weiwei, Xiumin Yu, Weibo Shi, Zhao Chen, Huiying Liu, He Yu, Xiaoxue Xing e Tingfa Xu. "An Experimental Study on Combustion and Cycle-by-Cycle Variations of an N-Butanol Engine with Hydrogen Direct Injection under Lean Burn Conditions". Sensors 22, n.º 3 (6 de fevereiro de 2022): 1229. http://dx.doi.org/10.3390/s22031229.

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This study experimentally investigated the effects of hydrogen direct injection on combustion and the cycle-by-cycle variations in a spark ignition n-butanol engine under lean burn conditions. For this purpose, a spark ignition engine installed with a hydrogen and n-butanol dual fuel injection system was specially developed. Experiments were conducted at four excess air ratios, four hydrogen fractions(φ(𝐻2)) and pure n-butanol. Engine speed and intake manifold absolute pressure (MAP) were kept at 1500 r/min and 43 kPa, respectively. The results indicate that the θ0–10 and θ10–90 decreased gradually with the increase in hydrogen fraction. Additionally, the indicated mean effective pressure (IMEP), the peak cylinder pressure (Pmax) and the maximum rate of pressure rise ((dP/dφ)max) increased gradually, while their cycle-by-cycle variations decreased with the increase in hydrogen fraction. In addition, the correlation between the (dP/dφ)max and its corresponding crank angle became weak with the increase in the excess air coefficient (λ), which tends to be strongly correlated with the increase in hydrogen fraction. The coefficient of variation of the Pmax and the IMEP increased with the increase in λ, while they decreased obviously after blending in the hydrogen under lean burn conditions. Furthermore, when λ was 1.0, a 5% hydrogen fraction improved the cycle-by-cycle variations most significantly. While a larger hydrogen fraction is needed to achieve the excellent combustion characteristics under lean burn conditions, hydrogen direct injection can promote combustion process and is beneficial for enhancing stable combustion and reducing the cycle-by-cycle variations.

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42

Jalindar Shinde, Balu, e Karunamurthy. "Effect of excess air ratio and ignition timing on performance, emission and combustion characteristics of high speed hydrogen engine". IOP Conference Series: Earth and Environmental Science 1161, n.º 1 (1 de abril de 2023): 012006. http://dx.doi.org/10.1088/1755-1315/1161/1/012006.

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Abstract The main goal of automobile researchers is to develop internal combustion engines that are fuel efficient and emit zero pollutants. It can be inferred from prior research publications that lean burn conditions can significantly reduce emissions while improving engine efficiency. The lean-burn engine combustion temperatures are lower hence harmful emissions like NO are reduced. Gasoline fuels have a narrow equivalence ratio window hence it was necessary to evaluate the other alternative fuels with a wider equivalence ratio for using it in IC engines for better performance and fewer emissions. This experiment is conducted on a single-cylinder digital three-spark ignited electronic fuel injected (DTSI-EFI) single-cylinder, 4 stroke high-speed SI engine fuelled by hydrogen. The excess air ratios are changed and MBT timing was also optimized. Hydrogen has delivered the lowest emissions under lean conditions. This data gives guidelines for developing SI engines with hydrogen port fuel injection for meeting future emissions norms. This experimental attempt is to protect the environment from greenhouse gas (GHG) emissions. The highest Brake Thermal Efficiency (BTE) is recorded at the leaner condition (λ = 4) as 37.53%, the highest power output is 7.02 kW at λ=1.5. CO and THC emissions are absent in hydrogen fuel and NO emissions reduces towards lean combustion.

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43

CEN, P. L., e R. T. YANG. "ZEOLITE PSA CYCLES FOR PRODUCING A HIGH-PURITY HYDROGEN FROM A HYDROGEN-LEAN MIXTURE." Chemical Engineering Communications 78, n.º 1 (abril de 1989): 139–51. http://dx.doi.org/10.1080/00986448908940191.

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Yu, Xiumin, Yaodong Du, Ping Sun, Lin Liu, Haiming Wu e Xiongyinan Zuo. "Effects of hydrogen direct injection strategy on characteristics of lean-burn hydrogen–gasoline engines". Fuel 208 (novembro de 2017): 602–11. http://dx.doi.org/10.1016/j.fuel.2017.07.059.

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45

Kapoor, A., e R. T. Yang. "Separation of Hydrogen-Lean Mixtures for a High-Purity Hydrogen by Vacuum Swing Adsorption". Separation Science and Technology 23, n.º 1-3 (janeiro de 1988): 153–78. http://dx.doi.org/10.1080/01496398808057640.

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46

Beita, Jadeed, Midhat Talibi, Suresh Sadasivuni e Ramanarayanan Balachandran. "Thermoacoustic Instability Considerations for High Hydrogen Combustion in Lean Premixed Gas Turbine Combustors: A Review". Hydrogen 2, n.º 1 (8 de janeiro de 2021): 33–57. http://dx.doi.org/10.3390/hydrogen2010003.

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Hydrogen is receiving increasing attention as a versatile energy vector to help accelerate the transition to a decarbonised energy future. Gas turbines will continue to play a critical role in providing grid stability and resilience in future low-carbon power systems; however, it is recognised that this role is contingent upon achieving increased thermal efficiencies and the ability to operate on carbon-neutral fuels such as hydrogen. An important consideration in the development of gas turbine combustors capable of operating with pure hydrogen or hydrogen-enriched natural gas are the significant changes in thermoacoustic instability characteristics associated with burning these fuels. This article provides a review of the effects of burning hydrogen on combustion dynamics with focus on swirl-stabilised lean-premixed combustors. Experimental and numerical evidence suggests hydrogen can have either a stabilising or destabilising impact on the dynamic state of a combustor through its influence particularly on flame structure and flame position. Other operational considerations such as the effect of elevated pressure and piloting on combustion dynamics as well as recent developments in micromix burner technology for 100% hydrogen combustion have also been discussed. The insights provided in this review will aid the development of instability mitigation strategies for high hydrogen combustion.

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47

Beita, Jadeed, Midhat Talibi, Suresh Sadasivuni e Ramanarayanan Balachandran. "Thermoacoustic Instability Considerations for High Hydrogen Combustion in Lean Premixed Gas Turbine Combustors: A Review". Hydrogen 2, n.º 1 (8 de janeiro de 2021): 33–57. http://dx.doi.org/10.3390/hydrogen2010003.

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Hydrogen is receiving increasing attention as a versatile energy vector to help accelerate the transition to a decarbonised energy future. Gas turbines will continue to play a critical role in providing grid stability and resilience in future low-carbon power systems; however, it is recognised that this role is contingent upon achieving increased thermal efficiencies and the ability to operate on carbon-neutral fuels such as hydrogen. An important consideration in the development of gas turbine combustors capable of operating with pure hydrogen or hydrogen-enriched natural gas are the significant changes in thermoacoustic instability characteristics associated with burning these fuels. This article provides a review of the effects of burning hydrogen on combustion dynamics with focus on swirl-stabilised lean-premixed combustors. Experimental and numerical evidence suggests hydrogen can have either a stabilising or destabilising impact on the dynamic state of a combustor through its influence particularly on flame structure and flame position. Other operational considerations such as the effect of elevated pressure and piloting on combustion dynamics as well as recent developments in micromix burner technology for 100% hydrogen combustion have also been discussed. The insights provided in this review will aid the development of instability mitigation strategies for high hydrogen combustion.

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48

Shi, Wei Bo, Xiu Min Yu e Ping Sun. "Performance and Emissions of a Hydrogen-Gasoline SI Engine". Applied Mechanics and Materials 713-715 (janeiro de 2015): 243–46. http://dx.doi.org/10.4028/www.scientific.net/amm.713-715.243.

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When hydrogen is added to a gasoline fueled spark ignition engine the lean limit of the engine can be extended. Lean burn engines are inherently more efficient and have the potential for significantly lower NOx emissions. Thus, the purpose of this paper is to investigate the effect of hydrogen addition to gasoline-air mixture on the performance and exhaust emission characteristics of a spark ignition engine. Six excess air ratios are used ranging from 0.8 to 1.5. The amount of hydrogen added is 18.5% and 30% by energy fraction. The test engine is operated at 1500 rpm. From the experimental observations, the effect of hydrogen addition on thermal efficiency, specific fuel consumption, cyclic variations of the indicated mean effective pressure (IMEP), and emissions of CO, unburned hydrocarbons and NOx are analyzed.

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49

Galloni, Enzo, Davide Lanni, Gustavo Fontana, Gabriele D’Antuono e Simone Stabile. "Performance Estimation of a Downsized SI Engine Running with Hydrogen". Energies 15, n.º 13 (28 de junho de 2022): 4744. http://dx.doi.org/10.3390/en15134744.

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Hydrogen is a carbon-free fuel that can be produced in many ways starting from different sources. Its use as a fuel in internal combustion engines could be a method of significantly reducing their environmental impact. In spark-ignition (SI) engines, lean hydrogen–air mixtures can be burnt. When a gaseous fuel like hydrogen is port-injected in an SI engine, working with lean mixtures, supercharging becomes very useful in order not to excessively penalize the engine performance. In this work, the performance of a turbocharged PFI spark-ignition engine fueled by hydrogen has been investigated by means of 1-D numerical simulations. The analysis focused on the engine behavior both at full and partial load considering low and medium engine speeds (1500 and 3000 rpm). Equivalence ratios higher than 0.35 have been considered in order to ensure acceptable cycle-to-cycle variations. The constraints that ensure the safety of engine components have also been respected. The results of the analysis provide a guideline able to set up the load control strategy of a SI hydrogen engine based on the variation of the air to fuel ratio, boost pressure, and throttle opening. Furthermore, performance and efficiency of the hydrogen engine have been compared to those of the base gasoline engine. At 1500 and 3000 rpm, except for very low loads, the hydrogen engine load can be regulated by properly combining the equivalence ratio and the boost pressure. At 3000 rpm, the gasoline engine maximum power is not reached but, for each engine load, lean burning allows the hydrogen engine achieving much higher efficiencies than those of the gasoline engine. At full load, the maximum power output decreases from 120 kW to about 97 kW, but the engine efficiency of the hydrogen engine is higher than that of the gasoline one for each full load operating point.

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50

Tereza, A. M., G. L. Agafonov, E. K. Anderzhanov, A. S. Betev, S. P. Medvedev e S. V. Khomik. "Numerical Simulation of Autoignition Characteristics of Lean Hydrogen–Air Mixtures". Russian Journal of Physical Chemistry B 16, n.º 4 (agosto de 2022): 686–92. http://dx.doi.org/10.1134/s1990793122040297.

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