Bibliografias temáticas / Lean hydrogen

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Literatura científica selecionada sobre o tema "Lean hydrogen"

Autor: Grafiati
Publicado: 29 de março de 2025

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Artigos de revistas sobre o assunto "Lean hydrogen"

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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5

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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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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Teses / dissertações sobre o assunto "Lean hydrogen"

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Topinka, Jennifer A. (Jennifer Ann) 1977. "Knock behavior of a lean-burn hydrogen-enhanced engine concept". Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/34351.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2003.
Includes bibliographical references (p. 89-91).
Experiments to identify the knock trends of lean gasoline-air mixtures, and such mixtures enhanced with hydrogen (H2) and carbon monoxide (CO), were performed on a single-cylinder research engine with boosting capability. The experimental method used to investigate knock trends consisted of determining the octane number (ON) of the primary reference fuel (mixture of isooctane and n-heptane) supplied to the engine that just produced audible knock. All tests were completed at 1500 rpm, MBT spark timing, with coolant temperature at fully warmed-up conditions and intake air temperature at 200 C. Various relative air-fuel ratio (lambda) sweeps were performed, while holding different parameters constant. First, testing with primary reference fuels investigated knock limits of lean operation; selected tests were then repeated with H2 and CO-enhancement. These mixtures simulated 15% and 30% of the engine's gasoline being reformed in a plasmatron fuel.reformer. Experimental results show that leaner operation does not decrease the knock tendency of an engine under conditions where a fixed output torque is maintained; rather it slightly increases the octane requirement. The onset of knock does decrease with lean operation when the intake pressure is held constant, but engine torque is then reduced. When H2 and CO are added to the mixture, the knock susceptibility is reduced, as illustrated by a decrease in the measured octane number of the primary reference fuel resulting in knock. Experiments conducted with the addition of H2 show similar trends, but to a lesser degree. Therefore, both H2 and CO act as octane enhancers when added to a hydrocarbon-air mixture. The extent to which H2 and CO improve the knock resistance of a mixture can be estimated by finding the bond-weighted octane number for the mixture of fuels. To substantiate these. results, a chemical kinetic ignition model was used to predict autoigntion of the end-gas for various conditions and fuel-air mixtures. Predicted model trends of knock onset partially agree with experimental observations. A comprehensive isooctane chemistry mechanism was used to demonstrate that H2 and CO-enhancement are effective in lengthening the ignition delay, and thereby reduce knock tendency.
by Jennifer A. Topinka.
S.M.
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2

Goldwitz, Joshua A. (Joshua Arlen) 1980. "Combustion optimization in a hydrogen-enhanced lean burn SI engine". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/27061.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.
Includes bibliographical references (p. 95-97).
Lean operation of spark ignition (SI) automotive engines offers attractive performance incentives. Lowered combustion temperatures inhibit NO[sub]x pollutant formation while reduced manifold throttling minimizes pumping losses, leading to higher efficiency. These benefits are offset by the reduced combustion speed of lean mixtures, which can lead to high cycle-to-cycle variation and unacceptable engine behavior characteristics. Hydrogen-enhancement can suppress the undesirable consequences of lean operation by accelerating the combustion process, thereby extending the "lean limit." Hydrogen can be produced onboard the vehicle with a plasmatron fuel reformer device. Combustion optimization experiments focused on three key areas: the ignition system, charge motion in the inlet ports, and mixture preparation. The ignition system tests compared a standard inductive coil scheme against high-energy discharge systems. Charge motion experiments focused on the impact of turbulence patterns generated by conventional restrictor plates as well as novel inlet flow modification cones. The turbulent motion of each configuration was characterized using swirl and tumble flow benches. Mixture preparation tests compared a standard single-hole pintle injector against a fine atomizing 12-hole injector. Lastly, a further series of trials was also run to investigate the impact of high exhaust gas recirculation (EGR) dilution rates on combustion stability. Results indicate that optimizations of the combustion system in conjunction with hydrogen-enhancement can extend the lean limit of operation by roughly 25% compared against the baseline configuration. Nearly half of this improvement may be attributed to improvements in the combustion system.
(cont.) An inductive ignition system in conjunction with a high tumble-motion inlet configuration leads to the highest levels of combustion performance. Furthermore, hydrogen enhancement affects a nearly constant absolute improvement in the lean misfire limit regardless of baseline combustion behavior. Conversely, the amount of improvement in the point of peak engine NIMEP output is inversely related to the level of baseline performance.
by Joshua A. Goldwitz.
S.M.
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3

Sykes, David Michael. "Design and Evaluation of a Lean-Premixed Hydrogen Injector with Tangential Entry in a Sector Combustor". Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/31722.

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Hydrogen use in a gas turbine engine has many benefits. Chief among these is the elimination of carbon based emissions. The only products and emissions from the combustion process are water vapor and oxides of nitrogen (NOx). However due to the lower flammability limit of hydrogen, it can be burned at much lower equivalence ratios that typical hydrocarbon fuels, and thus reducing the emissions of NOx. Multiple efforts have been made for the design of premixing injectors for gaseous hydrocarbon fuels, but very few attempts have been made for hydrogen.

To this end a premixing hydrogen injector was designed for the cruise engine condition for a PT6-20 turboprop engine. Swirl generated by tangential entry was utilized as a means to enhance mixing and as a convenient means to stabilize the flame. A prototype was designed to prevent flashback and promote a high degree of mixing, as well as a test combustor to evaluate the performance of the injector at scaled engine conditions. Numerical simulations were also performed to analyze the flowfield at the engine conditions. Performance and emissions data are used to draw conclusions about the feasibility of the injectors in the PT6 engine.
Master of Science

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4

Ivanic, Žiga 1978. "Predicting the behavior of a lean-burn hydrogen-enhanced engine concept". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/17932.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.
Includes bibliographical references (p. 90-91).
(cont.) Lean operation of a spark ignition (SI) internal combustion engine (ICE) offers attractive performance incentives. Lowered combustion temperatures inhibit formation of nitrogen oxides (NOx), while reduced intake manifold throttling minimizes pumping losses leading to higher efficiency. These benefits are offset by the reduced combustion speed of lean mixtures, which can lead to high cycle-to-cycle variation and unacceptable engine behavior characteristics. Hydrogen-enhancement can suppress the undesirable consequences of lean operation by accelerating the combustion process, thereby extending the "lean limit." Hydrogen would be produced on-board the vehicle with a fuel reforming device. Since operating an engine in the lean regime requires a significant amount of air, boosting is required. Hydrogen is also an octane enhancer, enabling operation at higher compression ratios, which results in a further improvement in engine efficiency. The focus of this thesis is on the modeling aspect of the lean boosted engine concept. Modeling provides a useful tool for investigating different lean boosted concepts and comparing them based on their emissions and fuel economy. An existing architectural concept has been tailored for boosted, hydrogen-enhanced, lean-bum SI engine. The simulation consists of a set of Matlab models, part physical and part empirical, that have been developed to simulate performance of a real ICE. The model was calibrated with experimental data for combustion and emissions in regards to changes in air/fuel ratio, load and speed, and different reformate fractions. The outputs of the model are NOx emissions and brake specific fuel consumption (BSFC) maps along with the cumulative NOx emissions and fuel economy for the urban
(cont.) and highway drive cycles.
by Žiga Ivanic.
S.M.
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Ross, Martin C. Shepherd J. E. "Lean combustion characteristics of hydrogen-nitrous oxide-ammonia mixtures in air /". Diss., Pasadena, Calif. : California Institute of Technology, 1997. http://resolver.caltech.edu/CaltechETD:etd-01182008-143226.

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Villarreal, Daniel Christopher. "Digital Fuel Control for a Lean Premixed Hydrogen-Fueled Gas Turbine Engine". Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/34974.

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Hydrogen-powered engines have been gaining increasing interest due to the global concerns of the effects of hydrocarbon combustion on climate change. Gas turbines are suitable for operation on hydrogen fuel. This thesis reports the results of investigations of the special requirements of the fuel controller for a hydrogen gas turbine. In this investigation, a digital fuel controller for a hydrogen-fueled modified Pratt and Whitney PT6A-20 turboprop engine was successfully designed and implemented. Included in the design are safety measures to protect the operating personnel and the engine. A redundant fuel control is part of the final design to provide a second method of managing the engine should there be a malfunction in any part of the primary controller.

Parallel to this study, an investigation of the existing hydrogen combustor design was performed to analyze the upper stability limits that were restricting the operability of the engine. The upstream propagation of the flame into the premixer, more commonly known as a flashback, routinely occurred at 150 shaft horsepower during engine testing. The procedures for protecting the engine from a flashback were automated within the fuel controller, significantly reducing the response time from the previous (manual) method. Additionally, protection measures were added to ensure the inter-turbine temperature of the engine did not exceed published limits. Automatic engine starting and shutdown procedures were also added to the control logic, minimizing the effort needed by the operator. The tested performance of the engine with each of the control functions demonstrated the capability of the controller.

Methods to generate an engine-specific fuel control map were also studied. The control map would not only takes into account the operability limits of the engine, but also the stability limits of the premixing devices. Such a map is integral in the complete design of the engine fuel controller.
Master of Science

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Perry, Matthew Vincent. "An Investigation of Lean Premixed Hydrogen Combustion in a Gas Turbine Engine". Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/43532.

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As a result of growing concerns about the carbon emissions associated with the combustion of conventional hydrocarbon fuels, hydrogen is gaining more attention as a clean alternative. The combustion of hydrogen in air produces no carbon emissions. However, hydrogen-air combustion does have the potential to produce oxides of nitrogen (NOx), which are harmful pollutants. The production of NOx can be significantly curbed using lean premixed combustion, wherein hydrogen and air are mixed at an equivalence ratio (the ratio of stoichiometric to actual air in the combustion process) significantly less than 1.0 prior to combustion. Hydrogen is a good candidate for use in lean premixed systems due to its very wide flammability range. The potential for the stable combustion of hydrogen at a wide range of equivalence ratios makes it particularly well-suited to application in gas turbines, where the equivalence ratio is likely to vary significantly over the operating range of the machine.

The strong lean combustion stability of hydrogen-air flames is due primarily to high reaction rates and the associated high turbulent burning velocities. While this is advantageous at low equivalence ratios, it presents a significant danger of flashbackâ the upstream propagation of the flame into the premixing deviceâ at higher equivalence ratios. An investigation has been conducted into the operation of a specific hydrogen-air premixer design in a gas turbine engine. Laboratory tests were first conducted to determine the upper stability limits of a single premixer. Tests were then carried out in which eighteen premixers and a custom-fabricated combustor liner were installed in a modified Pratt and Whitney Canada PT6A-20 turboprop engine. The tests examined the premixer and engine operability as a result of the modifications. A computer cycle analysis model was created to help analyze and predict the behavior of the modified engine and premixers. The model, which uses scaled component maps to predict off-design engine performance, was integral in the analysis of premixer flashback which limited the operation of the modified engine.
Master of Science

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8

Farina, Jordan Thomas. "Conversion of a Gas Turbine Engine to Operate on Lean-Premixed Hydrogen-Air: Design and Characterization". Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31067.

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The continued use of fossil fuels along with a rise in energy demand has led to increasing levels of carbon emissions over the past years. The purpose of this research was to design a lean premixed hydrogen fuel system that could be readily retrofit into an existing gas turbine engine to provide a clean renewable energy solution to this growing problem. There were major hurdles that had to be overcome to develop a hydrogen fuel system that would be practical, stable, and would fit into the existing space. High flame temperatures coupled with high flame speeds are major concerns when switching from jet fuel or natural gas to hydrogen. High temperatures lead to formations of pollutants such as oxides of nitrogen (NOx) and can potentially cause damage to critical engine components. High flame speeds can lead to dangerous flashbacks in the fuel premixers. Past researches have developed various hydrogen premixers to combat these problems. This research designed and developed new hydrogen premixers using information gathered from these designs and utilized new ideas to address their shortcomings.

A gas turbine engine was modified using 14 premixers and a matching combustor liner to provide lean operation with the existing turbomachinery. The engine was successfully operated using hydrogen while maintaining normal internal temperatures and practically eliminating the NOx emissions when compared to normal Jet-A operation. Even though full power operation was never achieved due to flashbacks in two premixers, this research demonstrated the feasibility of using lean-premixed hydrogen in gas turbine engines.
Master of Science

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9

Speth, Raymond L. 1981. "Effects of curvature and strain on a lean premixed methane-hydrogen-air flame". Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35640.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.
Includes bibliographical references (leaves 74-77).
The elemental flame is a subgrid model for turbulent combustion, parameterized by time-varying strain rate and curvature. This thesis develops the unsteady one-dimensional governing equations for the elemental flame incorporating detailed chemical kinetics and transport and a robust and efficient numerical method for solving the governing equations. Hydrogen enrichment of some hydrocarbon fuels has been shown to improve stability and extend flammability limits of lean premixed combustion in a number of recent experiments. It is suggested that these trends may be explained by the impact of hydrogen on the flame response to stretch and curvature. The elemental flame model is used to simulate premixed hydrogen-enriched methane flames in positively curved, negatively curved and planar configurations at varying strain rates. Curvature and stretch couple with non-unity species Lewis numbers to affect the burning rates and flame structure. Hydrogen addition is found to increase burning rate and resistance to flame stretch under all conditions. Positive curvature reinforces the effect of hydrogen enrichment, while negative curvature diminishes it.
(cont.) The effects of strong curvature cannot be explained solely in terms of flame stretch. Hydrogen enriched flames display increases in radical concentrations and a broadening of the reaction zone. Detailed analysis of the chemical kinetics shows that high strain rates lead to incomplete oxidation; hydrogen addition tends to mitigate this effect.
by Raymond Levi Speth.
S.M.
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Coleman, Marc David. "Catalytic reduction of nitrogen monoxide using hydrogen at low temperatures under lean burn conditions". Thesis, University of Reading, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246453.

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Livros sobre o assunto "Lean hydrogen"

1

Thorne, L. R. Platinum catalytic igniters for lean hydrogen-air mixtures. Washington, DC: Division of Engineering, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1988.

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2

Seymour, Dave. STS-35 scrub 3 hydrogen leak analysis. [Marshall Space Flight Center, Ala.]: National Aeronautics and Space Administration, George C. Marshall Space Flight Center, 1991.

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Seymour, Dave. STS-35 scrub 3 hydrogen leak analysis. [Marshall Space Flight Center, Ala.]: National Aeronautics and Space Administration, George C. Marshall Space Flight Center, 1991.

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4

W, Hunter Gary, e United States. National Aeronautics and Space Administration., eds. A hydrogen leak detection system for aerospace and commercial applications. [Washington, D.C.]: National Aeronautics and Space Administration, 1995.

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5

United States. National Aeronautics and Space Administration., ed. The use of spontaneous Raman scattering for hydrogen leak detection. [Washington, D.C.]: National Aeronautics and Space Administration, 1994.

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6

Noble, E. G. Solubilities of bromide salts of aluminum, cobalt, lead, manganese, potassium, and sodium when sparged with hydrogen bromide. Pgh. [i.e. Pittsburgh] Pa: U.S. Dept. of the Interior, Bureau of Mines, 1988.

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7

United States. National Aeronautics and Space Administration., ed. A study of (OI) 63.2 and 145.5 Micron emission from M17 and SGR A from the Lear Jet: Final report, for the period 1 October 1982 to 31 March 1986. Cambridge, Mass: Smithsonian Institution, Astrophysical Observatory, 1986.

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8

Board, California Air Resources. Prospects for attaining the state ambient air quality standards for suspended particulate matter (PM10), visibility reducing particles, sulfates, lead, and hydrogen sulfide. Sacramento, Calif. (P.O. Box 2815, Sacramento 95812): Air Resources Board, 1991.

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9

Griepink, B. The certification of the contents (mass fraction) of carbon, hydrogen, nitrogen, chlorine, arsenic, cadmium, manganese, mercury, lead, selenium, vanadium and zinc in three coals: Gas coal CRM No.180, coking coal CRM No.181, steam coal CRM No.182. Luxembourg: Commission of the European Communities, 1986.

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10

Biswas, Sayan. Physics of Turbulent Jet Ignition: Mechanisms and Dynamics of Ultra-lean Combustion. Springer, 2019.

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Capítulos de livros sobre o assunto "Lean hydrogen"

1

Nemitallah, Medhat A., Mohamed A. Habib e Ahmed Abdelhafez. "Fuel/Oxidizer-Flexible Lean Premixed Combustion". In Hydrogen for Clean Energy Production: Combustion Fundamentals and Applications, 93–151. Singapore: Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-7925-3_3.

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2

Saini, Rohit, Ashoke De e S. Gokulakrishnan. "Direct Numerical Simulation Study of Lean Hydrogen/Air Premixed Combustion". In Energy for Propulsion, 267–91. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7473-8_11.

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Nemitallah, Medhat A., Mohamed A. Habib e Ahmed Abdelhafez. "Application of Lean Premixed Combustion for Emission Control in Different Combustors". In Hydrogen for Clean Energy Production: Combustion Fundamentals and Applications, 213–92. Singapore: Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-7925-3_5.

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Wallace, James S. "Emissions and Efficiency of Turbocharged Lean-Burn Hydrogen-Supplemented Natural Gas Fueled Engines". In Enriched Methane, 147–73. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-22192-2_9.

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Zhang, Beidong, Yankun Jiang e Ruixin Wang. "Research on the Lean Burn Characteristics of Gasoline Engine Blending with Hydrogen-Rich Gas". In Environmental Science and Engineering, 763–71. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-63901-2_49.

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Sen, Asok K., M. Akif Ceviz e Erdogan Guner. "A Statistical Analysis of Lean Misfires in a Gasoline Engine and the Effect of Hydrogen Addition". In Progress in Exergy, Energy, and the Environment, 1055–60. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-04681-5_100.

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Donini, A., R. J. M. Bastiaans, J. A. van Oijen, M. S. Day e L. P. H. de Goey. "A Priori Assessment of the Potential of Flamelet Generated Manifolds to Model Lean Turbulent Premixed Hydrogen Combustion". In ERCOFTAC Series, 315–20. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-2482-2_50.

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Lodi Rizzini, E., L. Venturelli e N. Zurlo. "Antihydrogen (hydrogen) atom formation". In EXA/LEAP 2008, 313–19. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-02803-8_46.

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Hann, S., L. Urban, Michael Grill e M. Bargende. "Prediction of burn rate, knocking and cycle-to-cycle variations of methane / hydrogen mixtures in stoichiometric and lean engine operation conditions". In Proceedings, 58–80. Wiesbaden: Springer Fachmedien Wiesbaden, 2017. http://dx.doi.org/10.1007/978-3-658-19012-5_4.

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Petitjean, Claude. "Muon capture in hydrogen and deuterium". In EXA/LEAP 2008, 109–14. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-02803-8_17.

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Trabalhos de conferências sobre o assunto "Lean hydrogen"

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Kido, Hiroyuki, Masaya Nakahara, Kenshiro Nakashima e Jun-Hyo Kim. "Turbulent Burning Velocity of Lean Hydrogen Mixtures". In 2003 JSAE/SAE International Spring Fuels and Lubricants Meeting. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2003. http://dx.doi.org/10.4271/2003-01-1773.

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Patnaik, G., e K. Kailasanath. "Cellular structure of lean hydrogen and methane flames". In 30th Joint Propulsion Conference and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1994. http://dx.doi.org/10.2514/6.1994-3275.

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PATNAIK, G., e K. KAILASANATH. "Cellular structure of lean hydrogen flames in microgravity". In 28th Aerospace Sciences Meeting. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1990. http://dx.doi.org/10.2514/6.1990-41.

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Hernandez-Perez, Francisco, Clinton Groth e Omer Gulder. "LES of a Hydrogen-Enriched Lean Turbulent Premixed Flame". In 51st AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2013. http://dx.doi.org/10.2514/6.2013-1139.

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Zhu, Shengrong, e Sumanta Acharya. "Flame Dynamics With Hydrogen Addition at Lean Blowout Limits". In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-95822.

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Lean premixed combustion is widely used in power generation due to the low nitric oxide emissions. Recent interest in syngas requires a better understanding of the role of hydrogen addition on the combustion process. In the present study, the extinction process of hydrogen enriched premixed flames near Lean Blow Out (LBO) in a swirl-stabilized combustor has been examined in both unconfined and confined configurations. High speed images of the flame chemiluminescence are recorded and a proper orthogonal decomposition (POD) procedure is used to extract the dominant flame dynamics during the LBO process. By examining the POD modes, the spectral information and the statistical properties of POD coefficients, the effect of hydrogen addition on the LBO processes are analyzed and described in the paper. Results show that in unconfined flames, the shear layer mode along with flame rotation with local quenching and re-ignition is dominant in the methane-only case. For the open hydrogen enriched flames, the extinction times are longer and are linked to the lower minimum ignition energy for hydrogen that facilitates re-ignition events. In confined methane flames, a conical flame is observed and the POD mode representing the burning in the central recirculation zone appears to be dominant. For the 60% hydrogen enriched flame, a columnar burning pattern is observed and the fluctuation energies are evenly spread across several POD modes making this structure more prone to external disturbances and shorter extinction times.
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Wallace, James S., Liviu Segal e James F. Keffer. "Lean Mixture Operation of Hydrogen-Fueled Spark Ignition Engines". In 1985 SAE International Fall Fuels and Lubricants Meeting and Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1985. http://dx.doi.org/10.4271/852119.

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PATNAIK, G., e K. KAILASANATH. "Lean flammability limit of downward propagating hydrogen-air flames". In 30th Aerospace Sciences Meeting and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1992. http://dx.doi.org/10.2514/6.1992-336.

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Zhu, Shengrong, e Sumanta Acharya. "Dynamics of Lean Blowout in Premixed Combustion With Hydrogen Addition". In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-69189.

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An experimental study of lean premixed combustion in a swirl-stabilized combustor is undertaken to characterize the dynamics and time scales close to Lean Blow Out (LBO) conditions. Due to the recent interest in syngas fuels, the effect of hydrogen addition on LBO is studied. In present study, both confined and unconfined turbulent methane air premixed flames have been examined with different hydrogen levels during the extinction transition with high speed imaging of OH* chemiluminescence at 2 KHz. Planar laser induced fluorescence measurement of OH is also performed for studying the flame structure. The blowout conditions are approached by reducing the flow rate of fuel mixture or the equivalence ratio with constant air flow rate. The estimated extinction times from high speed imaging and corresponding flame structures are analyzed and compared between confined and unconfined flames with different hydrogen blends. The extinction time scale and the heat release fluctuations show inverse trends with hydrogen addition for the confined and unconfined flames, and are indicative of different stabilization and blow out mechanisms for the two configurations. These mechanisms which involve heat losses from the flame, inner- and corner recirculation zones and unsteady flame dynamics are described in the paper.
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West, Brian, Shean Huff, James Parks, Matt Swartz e Ron Graves. "In-Cylinder Production of Hydrogen During Net-Lean Diesel Operation". In SAE 2006 World Congress & Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2006. http://dx.doi.org/10.4271/2006-01-0212.

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Goldwitz, Joshua A., e John B. Heywood. "Combustion Optimization in a Hydrogen-Enhanced Lean-Burn SI Engine". In SAE 2005 World Congress & Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2005. http://dx.doi.org/10.4271/2005-01-0251.

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Relatórios de organizações sobre o assunto "Lean hydrogen"

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Schefer, Robert W. Evaluation of NASA Lean Premixed Hydrogen Burner. Office of Scientific and Technical Information (OSTI), janeiro de 2003. http://dx.doi.org/10.2172/811192.

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Erlendur Steinthorsson, Brian Hollon e Adel Mansour. Micro-Mixing Lean-Premix System for Ultra-Low Emission Hydrogen/Syngas Combustion. Office of Scientific and Technical Information (OSTI), junho de 2010. http://dx.doi.org/10.2172/1030641.

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Chad Smutzer. Application of Hydrogen Assisted Lean Operation to Natural Gas-Fueled Reciprocating Engines (HALO). Office of Scientific and Technical Information (OSTI), janeiro de 2006. http://dx.doi.org/10.2172/885936.

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Beurlot, Kyle, e Timothy Jacobs. PR457-242002-R01 Hydrogen and Natural Gas Mixtures in 2 Stroke Engines for Methane Reductions. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), fevereiro de 2025. https://doi.org/10.55274/r0000108.

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Large-bore natural gas two-stroke engines with lean-burn technology have been integral to the North American pipeline network for many years and will remain crucial for future gas transportation. As research focuses on achieving lower lean ignition limits, pre-combustion chambers have gained attention as a promising method to enhance combustion stability and engine reliability. However, retrofitting existing platforms with pre-combustion chambers may not always be financially viable, which calls for further exploration of alternative technologies that could reduce methane emissions from two-stroke open-chamber (OC) engines. Hydrogen dithering in natural gas has demonstrated potential for methane emissions reduction, yet significant gaps in understanding persist, particularly in terms of its impact on other pollutants like nitrogen oxides (NOx). This study intends to further research on evaluating various concentrations of hydrogen gas blended into a natural gas fuel stream on an OC engine platform as a pathway to reduce methane emissions. The resulting effects were then thoroughly analyzed to assess the impact on general combustion performance, including main chamber pressure, temperature, heat release rate, emissions, power levels, and rate of pressure rise.
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Olsen, Daniel, e Azer Yalin. L52360 NOx Reduction Through Improved Precombustion Chamber Design. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), dezembro de 2018. http://dx.doi.org/10.55274/r0011536.

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several objectives were Several objectives were completed. First, a literature review was performed to assess the current technological state of prechambers. This includes state of the art design, reliability surveys, and proven prechamber design criteria. This is an enabling tool for developing new prechamber concepts for year 2 of the project. The prioritized concepts are (in order): - Improved prechamber geometry - apply high speed engine prechamber design and scale up for large bore engines. - Adiabatic prechamber - traditional prechamber will ceramic lining to reduce heat transfer to the prechamber cooling jacket - Natural Gas Reforming - reform prechamber natural gas (roughly 3% of total engine fueling) into CO and hydrogen for low emission, high flame speed ignition. - Micro Prechamber Geometry - non-fueled and fueled micro prechambers for igniting lean engine mixtures with low NOx contribution on engine out emissions (2 concepts). - Develop diagnostic tools to evaluate the performance of prechamber concepts. The tools developed were combustion visualization utilizing high speed cameras, heat release analysis, and spectroscopy.
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Hartmann, Kevin, William Buttner, Robert Burgess e Carl Rivkin. Passive Leak Detection Using Commercial Hydrogen Colorimetric Indicator. Office of Scientific and Technical Information (OSTI), setembro de 2016. http://dx.doi.org/10.2172/1326889.

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Brosha, Eric L., Fernando H. Garzon, Cortney Kreller, Rangachary Mukundan, Bob Glass e Leta Woo. Leak Detection and H2 Sensor Development for Hydrogen Applications. Office of Scientific and Technical Information (OSTI), julho de 2013. http://dx.doi.org/10.2172/1088919.

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Brosha, Eric L. Leak Detection and H2 Sensor Development for Hydrogen Applications. Office of Scientific and Technical Information (OSTI), julho de 2012. http://dx.doi.org/10.2172/1045975.

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Cialone, H., D. N. Williams e T. P. Groeneveld. L51621 Hydrogen-Related Failures at Mechanically Damaged Regions. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), setembro de 1991. http://dx.doi.org/10.55274/r0010313.

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Leaks attributed to hydrogen-stress cracking (HSC) initiating in regions of mild mechanical damage have been reported in cathodically protected pipe lines constructed from high-strength, microalloyed, controlled-rolled steels. The hydrogen is believed to be present in service from the cathodic potential applied. Laboratory studies were initiated to determine the factors that contributed to those unexpected failures. Strain aging at ambient temperatures as a result of deformation introduced during the mechanical damage, was found to be a significant factor. Smooth-bar specimens that were strained and then aged failed by HSC within one week, whereas specimens that were not strain aged did not fail by HSC. Result: The findings of this research indicate a potential sequence of events which may lead to hydrogen-related failures in regions of mild mechanical damage: (1) Following the damage, ambient-temperature strain aging which promotes sensitivity to HSC takes place in the mechanically damaged region, in a surface layer of the pipe wall which has been subjected to a critical level of strain. The time period for this step would be on the order of several years. (2) Electrochemical conditions which promote hydrogen charging develop at the pipe surface from the cathodic current applied (or possibly corrosion). (3) Local stresses in the mechanically damaged region are elevated above the threshold stress for HSC by the moderate stress concentration provided by the mechanical damage. For the X70 pipe studied, the stress elevation should be at least 20 percent above the nominal hoop stress. (4) An HSC crack initiates and grows in the strain-aged surface layer. (5) The crack propagates further by HSC, through the non-strain-aged portion of the wall, as a result of the high stress concentration at the crack tip. (6) When the crack grows to a critical depth, it propagates rapidly through the wall by overload and causes a leak.
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Fiore e Boring. L52233 Evaluation of Hydrogen Cracking in Weld Metal Deposited Using Cellulosic-Coated Electrodes. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), outubro de 2006. http://dx.doi.org/10.55274/r0010378.

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Cellulosic-coated electrodes (primarily AWS EXX10-type) are traditionally used for "stovepipe" welding of pipelines because they are well suited for deposition of pipeline girth welds and are capable of high deposition rates when welding downhill. Despite advances in mechanized welding technology, development of low-hydrogen self-shielded flux-cored arc welding (FCAW) consumables, and substantial improvement of basic-coated low-hydrogen vertical-down shielded metal arc welding (SMAW) electrodes, manual pipeline welding using cellulosic-coated electrodes is still widely utilized throughout the world. Cellulosic-coated electrodes are also used for critical applications in offshore pipeline construction such as tie-in welds and repair welds.Hydrogen-assisted cracking can occur in both the weld metal and heat-affected zone (HAZ) regions of a welded joint, although HAZ hydrogen cracking is more common. Extensive work was undertaken in the 1970s and 1980s to study HAZ hydrogen cracking, and guidelines were developed to avoid HAZ hydrogen cracking by controlling heat input and preheat. Improvements in steelmaking practice and the trend toward leaner chemistries have also helped to alleviate HAZ hydrogen cracking. The primary objectives of this project are to further define the conditions that can lead to hydrogen cracking in weld metal deposited using cellulosic-coated electrodes, in terms of operator preference (arc length), electrode properties, power supply selection, and materials handling. The results of the project are being used to develop welding guidelines, and if applicable, re-hydration guidelines to prevent weld metal hydrogen cracking.
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