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Journal articles on the topic 'Descriptions of fuels'
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1
Wzorek, Małgorzata. "Optimization of fuels from waste composition with application of genetic algorithm." Waste Management & Research: The Journal for a Sustainable Circular Economy 32, no. 5 (April 9, 2014): 423–33. http://dx.doi.org/10.1177/0734242x14529618.
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The objective of this article is to elaborate a method to optimize the composition of the fuels from sewage sludge (PBS fuel – fuel based on sewage sludge and coal slime, PBM fuel – fuel based on sewage sludge and meat and bone meal, PBT fuel – fuel based on sewage sludge and sawdust). As a tool for an optimization procedure, the use of a genetic algorithm is proposed. The optimization task involves the maximization of mass fraction of sewage sludge in a fuel developed on the basis of quality-based criteria for the use as an alternative fuel used by the cement industry. The selection criteria of fuels composition concerned such parameters as: calorific value, content of chlorine, sulphur and heavy metals. Mathematical descriptions of fuel compositions and general forms of the genetic algorithm, as well as the obtained optimization results are presented. The results of this study indicate that the proposed genetic algorithm offers an optimization tool, which could be useful in the determination of the composition of fuels that are produced from waste.
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Riccardi, Cynthia L., Susan J. Prichard, David V. Sandberg, and Roger D. Ottmar. "Quantifying physical characteristics of wildland fuels using the Fuel Characteristic Classification SystemThis article is one of a selection of papers published in the Special Forum on the Fuel Characteristic Classification System." Canadian Journal of Forest Research 37, no. 12 (December 2007): 2413–20. http://dx.doi.org/10.1139/x07-175.
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Wildland fuel characteristics are used in many applications of operational fire predictions and to understand fire effects and behaviour. Even so, there is a shortage of information on basic fuel properties and the physical characteristics of wildland fuels. The Fuel Characteristic Classification System (FCCS) builds and catalogues fuelbed descriptions based on realistic physical properties derived from direct or indirect observation, inventories, expert knowledge, inference, or simulated fuel characteristics. The FCCS summarizes and calculates wildland fuel characteristics, including fuel depth, loading, and surface area. Users may modify fuelbeds and thereby capture changing fuel conditions over time and (or) under different management prescriptions. Fuel loadings from four sample fuelbed pairs (i.e., pre- and post-prescribed fire) were calculated and compared by using FCCS to demonstrate the versatility of the system and how individual fuel components, such as shrubs, nonwoody fuels, woody fuels, and litter, can be calculated and summarized. The ability of FCCS to catalogue and summarize complex fuelbeds and reflect dynamic fuel conditions allows calculated results to be used in a variety of applications including surface and crown fire predictions, carbon assessments, and wildlife habitat management.
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Volkova, Liubov, Andrew L. Sullivan, Stephen H. Roxburgh, and Christopher J. Weston. "Visual assessments of fuel loads are poorly related to destructively sampled fuel loads in eucalypt forests." International Journal of Wildland Fire 25, no. 11 (2016): 1193. http://dx.doi.org/10.1071/wf15223.
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Fire managers around the world commonly use visual assessment of forest fuels to aid prediction of fire behaviour and plan for hazard reduction burning. In Australia, fuel hazard assessment guides also allow conversion of visual assessments to indicative fuel loads, which is essential for some rate of spread models and calculation of fireline intensity or emissions. The strength of correlation between fuel hazard and destructively sampled (directly measured) fuel load was tested using a comprehensive dataset of >500 points from across a range of eucalypt forests in Australia. Overall, there was poor correlation between the assigned fuel hazard rating and measured biomass for surface, near-surface and elevated fuel components, with a clear tendency for these systems to under-predict fuel load at low hazard ratings, and over-predict it at high hazard ratings. Visual assessment of surface fuels was not statistically different from a random allocation of hazard level. The considerable overlap in fuel load between hazard ratings at higher ranges suggests the need to reduce the number of hazard classes to provide clearer differentiation of fuel hazard. To accurately assess forest fuel condition, improvements in fuel hazard descriptions and calibration of visual assessment with destructively measured fuels is essential.
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Fry, Danny L., and Scott L. Stephens. "Stand-level spatial dependence in an old-growth Jeffrey pine – mixed conifer forest, Sierra San Pedro Mártir, Mexico." Canadian Journal of Forest Research 40, no. 9 (September 2010): 1803–14. http://dx.doi.org/10.1139/x10-122.
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Descriptions of spatial patterns are important components of forest ecosystems, providing insights into functions and processes, yet basic spatial relationships between forest structures and fuels remain largely unexplored. We used standardized omnidirectional semivariance modeling to examine the spatial pattern of fuels and forest structure measured in a systematic nested plot grid covering 144 ha. Forest structure variables were spatially dependent at scales ranging from 62 to 572 m. Cross-variograms of fuels and forest structure showed both positive and negative correlations, ranging from 0.04 to 0.67. Notably, fine fuels were correlated positively and negatively with forest structure variables of white fir ( Abies concolor (Gord. & Glend.) Lindl. ex Hildebr.) and Jeffrey pine ( Pinus jeffreyi Balf.), respectively. Old-growth Jeffrey pine – mixed conifer forest within the study area exhibited both identifiable spatial correlations and high stand-level spatial heterogeneity, as demonstrated by the influence of outliers on the underlying spatial pattern. The spatial dependency of fuels with species-specific variables suggests that less common species may have a large influence in the characterization of forest attributes and that fuel classifications may be improved by accounting for the spatial distributions of overstory species. Spatial correlations have many applications to forest management, including the classification and mapping of forest structure, establishing guidelines for fuel treatments, and restoration of old-growth forest ecosystems.
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Sandberg, David V., Roger D. Ottmar, and Geoffrey H. Cushon. "Characterizing fuels in the 21st Century." International Journal of Wildland Fire 10, no. 4 (2001): 381. http://dx.doi.org/10.1071/wf01036.
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This paper was presented at the conference ‘Integrating spatial technologies and ecological principles for a new age in fire management’, Boise, Idaho, USA, June 1999 The ongoing development of sophisticated fire behavior and effects models has demonstrated the need for a comprehensive system of fuel classification that more accurately captures the structural complexity and geographic diversity of fuelbeds. The Fire and Environmental Research Applications Team (FERA) of the USDA Forest Service, Pacific Northwest Research Station, is developing a national system of fuel characteristic classification (FCC). The system is designed to accommodate researchers and managers operating at a variety of scales, and who have access to a variety of kinds of input data. Users can generate fuel characteristics by accessing existing fuelbed descriptions (fuelbed prototypes) using generic information such as cover type or vegetation form. Fuelbed prototypes will provide the best available predictions of the kind, quality and abundance of fuels. Users can accept these default settings or modify some or all of them using more detailed information about vegetation structure and fuel biomass. When the user has completed editing the fuelbed data, the FCC system calculates or infers quantitative fuel characteristics (physical, chemical, and structural properties) and probable fire parameters specific to that fuelbed. Each user-described fuelbed is also assigned to one of approximately 192 stylized fuel characteristic classes.
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Pettinari, M. Lucrecia, Roger D. Ottmar, Susan J. Prichard, Anne G. Andreu, and Emilio Chuvieco. "Development and mapping of fuel characteristics and associated fire potentials for South America." International Journal of Wildland Fire 23, no. 5 (2014): 643. http://dx.doi.org/10.1071/wf12137.
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The characteristics and spatial distribution of fuels are critical for assessing fire hazard, fuel consumption, greenhouse gas emissions and other fire effects. However, fuel maps are difficult to generate and update, because many regions of the world lack fuel descriptions or adequate mapped vegetation attributes to assign these fuelbeds spatially across the landscape. This paper presents a process to generate fuel maps for large areas using remotely sensed information and ancillary fuel characteristic data. The Fuel Characteristic Classification System was used to build fuelbeds for South America and predict potential fire hazard using a set of default environmental variables. A land-cover map was combined with a biome map to define 98 fuelbeds, and their parameters were assigned based on information from global datasets and existing Fuel Characteristic Classification System fuelbeds or photo series. The indices of potential surface fire behaviour ranged from 1.32 to 9, whereas indices of potential crown fire and available fuel for combustion had low to medium values (0–6). This paper presents a geospatial fuels map for South America. This map could be used to assess fire hazard, predict fire behaviour under defined environmental conditions or calculate fuel consumption and greenhouse gas emissions. It could also be easily updated as new remotely sensed information on vegetation becomes available.
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Govindaraju, Pavan B., and Matthias Ihme. "Formulation of optimal surrogate descriptions of fuels considering sensitivities to experimental uncertainties." Combustion and Flame 188 (February 2018): 337–56. http://dx.doi.org/10.1016/j.combustflame.2017.09.044.
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Hill, Malcolm R. "Energy, Environment and Technology in The Former Ussr: The Case of Fossil-Fuelled Power Stations and Acid Rain Emissions." Energy & Environment 8, no. 4 (December 1997): 247–67. http://dx.doi.org/10.1177/0958305x9700800401.
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This paper provides perspectives on atmospheric pollution in the former USSR, and the technological factors which influence the levels of these emissions. The first part of the paper provides an estimate of the scale of atmospheric pollution in the former USSR, with particular reference to acid rain emissions in general and from the power generation industry in particular; followed by a discussion of recent and future fuel preferences in the former Soviet region. This discussion is then followed by descriptions of the combustion processes used in the power generation industry in the former USSR, with attention being drawn to the levels of SOx and NOx emissions from these various fuels and processes. These emissions are compared with those from advanced combustion processes used in Western countries, and the paper is then concluded with a list of those technologies which are the most likely candidates for transfer to the former USSR for the reduction of acid rain emissions.
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simeti, mary taylor. "At the Prince's Table: Food in The Leopard." Gastronomica 7, no. 2 (2007): 64–70. http://dx.doi.org/10.1525/gfc.2007.7.2.64.
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The food so lovingly described by Tomasi di Lampedusa in his novel The Leopard is as rich in gastronomic history as it is in fragrance and flavor. The famous timbale gathers strands from all stages of Sicilian history, while the author also makes liberal use of other traditions such as that of pastries made by nuns. Each dish functions primarily as metaphor, most often for a decaying society and approaching death, but Lampedusa's own passionate love for good food fuels his sensuous descriptions, and his own tastes are revealed obliquely through the preferences of his protagonist.
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Nelson, Ralph M. "Re-analysis of wind and slope effects on flame characteristics of Mediterranean shrub fires." International Journal of Wildland Fire 24, no. 7 (2015): 1001. http://dx.doi.org/10.1071/wf14155.
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During the past 20 years, study of wind–slope-aided wildland fire behaviour with experimental burns and physical modelling methods has increased. As part of their continuing study of fires in Mediterranean shrub, F. Morandini and X. Silvani reported experimental temperatures, heat fluxes, flame characteristics and other fire behaviour variables measured on five wind–slope-aided fires. Calculating convection numbers and several convective Froude numbers, the authors concluded that these dimensionless variables for their two wind-dominated fires did not satisfy criteria identified in previous studies for determining mechanisms of heat transfer during fuel preheating. The present paper describes a re-analysis of the data based on a triangular flame model and alternative definitions of flame tilt angle and height. This new analysis has shown that the influence of slope on the fire behaviour was not accounted for; thus, the conclusion of Morandini and Silvani is questionable. Of the five dimensionless variables studied using criteria in the literature, the squared flame height convective Froude number best describes modes of heat transfer to unburned fuels during the experimental fires. Though these results come indirectly from field measurements, they confirm the need to include slope effects in descriptions of wind–slope-aided fire behaviour.
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Taskinen, Pekka, and Katri Avarmaa. "Simulation of Slag–Matte/Metal Equilibria for Complex and Low-Grade Raw Materials." Sustainability 13, no. 22 (November 19, 2021): 12826. http://dx.doi.org/10.3390/su132212826.
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The depleting and increasingly complex mineral resources bring challenges into the area of metal production, bringing new boundary conditions to the smelting and refining processes. Thermodynamics of phases and equilibria are the key to the analysis of pyrometallurgical processes, enabling descriptions of their limiting boundary conditions. The raw material basis of non-ferrous metals needs an effective control of iron oxide fluxing due to the challenging fact that the targeted metal values of, e.g., copper, nickel, lead, and tin will exist as minority components in the smelter feeds compared to iron sulphides, gangue, and many harmful elements. This means more complex slag compositions and the amount of produced slag being several times that of the metal production. This feature severely impacts the heat balance of the smelting vessels where autogenous operation without external fuels becomes more and more difficult to maintain.
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Ahmed, Reem, Chandra Mohan Sinnathambi, and Usama Eldmerdash. "Dynamic Studies of Refinery Sludge Gasification in Updraft Reactor." Applied Mechanics and Materials 625 (September 2014): 431–34. http://dx.doi.org/10.4028/www.scientific.net/amm.625.431.
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Many papers have been published about the gasification of different biomass fuels in fixed bed reactor. To date, no experimental analysis is available in the open literature on gasification of refinery sludge. Therefore the descriptions of dynamic temperature in an updraft reactor for a dry refinery sludge gasification are investigated in details. The rate of the temperature change with operation time and the temperature profiles inside the reactor are taken for various equivalent ratios. The dynamic results show that increasing the ER from 0.195 to 0.244 shift the combustion zone peak temperature from 858 °C to 986 °C and cause turbulence behavior in reduction zone temperature. With an ER of 0.195, the rate change of temperatures zones was found to be in the ± 50 OC min-1 indicating stable gasification process. The axial temperature for starting of a steady state gasification process was found to be between 20 to 60 min operation time in process.
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Menely, Tobias. "“The Present Obfuscation”: Cowper's Task and the Time of Climate Change." PMLA/Publications of the Modern Language Association of America 127, no. 3 (May 2012): 477–92. http://dx.doi.org/10.1632/pmla.2012.127.3.477.
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Climate change, I argue, is a catastrophe that resists the revelation promised by apocalyptic narrative. My case study is William Cowper's poem The Task (1785), which I situate in two climatic contexts: the year of its composition, which saw meteorological extremes caused by the eruption of an Icelandic volcano, and an era of geologic modernity, the Anthropocene, which commenced with the industrial combustion of fossil fuels in the late eighteenth century. As volcanogenic haze migrates in Cowper's descriptions from the countryside to the greenhouse and the imperial city, the poet fails to identify a meteorology with which to distinguish nature's seasonal “revolvency” from eschatological presages or from the modernization process itself—the historical “revolution” embodied by worsening urban pollution. Climate change poses a crisis, in the dual etymological senses of a decision and a turning point, because it unsettles the duration of the present, what returns and endures and so measures alteration.
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Keane, Robert E. "Describing wildland surface fuel loading for fire management: a review of approaches, methods and systems." International Journal of Wildland Fire 22, no. 1 (2013): 51. http://dx.doi.org/10.1071/wf11139.
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Wildland fuelbeds are exceptionally complex, consisting of diverse particles of many sizes, types and shapes with abundances and properties that are highly variable in time and space. This complexity makes it difficult to accurately describe, classify, sample and map fuels for wildland fire research and management. As a result, many fire behaviour and effects software prediction systems use a generalised description of fuels to simplify data collection and entry into various computer programs. There are several major fuel description systems currently used in the United States, Canada and Australia, and this is a source of confusion for many in fire management. This paper (1) summarises the challenges of describing fuels, (2) contrasts approaches (association, classification and abstraction) for developing fuel description systems and (3) discusses possible future directions in wildland fuel description and science to transition to a universal fuel description system. Most discussion centres on surface fuel loadings as the primary descriptive characteristic. This synthesis paper is intended to provide background for understanding surface fuel classification and description systems and their use in simulating fire behaviour and effects, quantifying carbon inventories and evaluating site productivity.
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Kumar, Deepak. "A short review on the advancement in the development of TiO2 and ZnO based photo-anodes for the application of Dye-Sensitized Solar Cells (DSSCs)." Engineering Research Express 3, no. 4 (December 1, 2021): 042004. http://dx.doi.org/10.1088/2631-8695/ac3b29.
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Abstract Population growth significantly expanding the boundaries of residential areas and living standards for humankind results in a tremendous increase in energy consumption. Unlike fossil fuels, which are found only in a few sites and non-renewable sources, solar energy is renewable and freely available in every part of the world. A dye-sensitized solar cell (DSSC) is a suitable electrochemical device to harness solar energy to produce power and is advantageous for its simplicity and inexpensive cost. Variations in photo-electrodes micro/nanostructure shape, doping, size, and crystal phase can improve the DSSCs performance by enhancing dye loading, improved light scattering ability, and/or faster electron transit and longer electron lifetime. The high yielding techniques for producing diverse morphologies for nanoparticles with appropriate band gaps might thus be considered another feasible strategy for improving cell performance. The impact of influencing parameters on photovoltaic characteristics of photo-anode for DSSC application is investigated in this review article. The descriptions are presented by compiling a list of relevant literature reports.
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Echevarria Huamán, Ruth Nataly. "Optimized Simulation of CO2 Removal Process from Coal Fired Power Plants with MEA by Sensitivity Analysis in Aspen plus." Labor e Engenho 11, no. 2 (June 30, 2017): 191. http://dx.doi.org/10.20396/labore.v11i2.8649743.
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The World Energy consumption has been increasing steadily since industrialization, this recent increase is also the major cause for the raise of CO2 concentration in the atmosphere. Fossil fuels play a central role in our energy consumption; actually the CCS technology and their operations in power systems must get a prominent role in reducing total CO2 emissions. An attempt to tackle the problem of solvent based Post Combustion Carbon Capture process optimization requires the availability of a rigorous process model along with a design methodology. During the modeling, much physical and chemical process should be considered in order to get more realistic results, this complexity process addressed as Reactive Separation. This report presents detailed descriptions of the process sections as well as technical documentation for the ASPEN Plus simulations including the design basis, models employed, key assumptions, design parameters, convergence algorithms, concentration and temperature profiles and calculated outputs. The main purpose is to minimize the amount of energy required in the desorption process through the optimum operating condition to the actual CO2 absorption experimental setup. The case of study is on MEA 30wt% in a coal Hired power plant. Electrolytic method is considered; the sensitive analysis was used for the Optimization.
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SIDOROWICZ, Maciej, and Ireneusz PIELECHA. "Inflammability evaluation of hydrocarbon fuels mixtures formed directly in the combustion chamber." Combustion Engines 170, no. 3 (August 1, 2017): 57–65. http://dx.doi.org/10.19206/ce-2017-309.
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The proposed article involves an investigation of the processes taking place during the preparation of mixed fuels that are combined directly before combustion. The fuel dose formed in this way must take into account the qualitative and quantitative composition of the fuels and the amount of air in the process. Given that liquid fuels similar to gasoline (e.g. methanol, ethanol, butanol) are characterized by different properties, their comparison would be useful in order to use their ratio to influence the combustion process. The process of fuel preparation plays a decisive role in this issue. The article describes abilities of modelling the injection of various fuels simultaneously to the combustion chamber for creating fuel mixture directly before ignition. First part of the article consists of analysis of light hydrocarbon fuels mixing abilities, supported with present research data. Next part describes the evaluation of execution of the assumed system – two fuel injectors with analysis of spray penetration. The modelling of the injection and spray was performed in the AVL FIRE 2014.2 environment and the results were presented. The injection possibility was proven by injecting the fuel to the combustion chamber model. Local values of air-fuel ratio, density and ambient pressure were presented to better understand the potential in mixing fuels directly before ignition. The conclusion includes description of fuel mixing abilities, influence of various fuels on creation of a stratified mixture and definition of controllability of charge ignition.
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Čupera, Jiří, Pavel Sedlák, and Petr Karafiát. "Differences in rheological profile of regular diesel and bio-diesel fuel." Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 58, no. 5 (2010): 67–74. http://dx.doi.org/10.11118/actaun201058050067.
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Biodiesel represents a promising alternative to regular fossil diesel. Fuel viscosity markedly influences injection, spraying and combustion, viscosity is thus critical factor to be evaluated and monitored. This work is focused on quantifying the differences in temperature dependent kinematic viscosity regular diesel fuel and B30 biodiesel fuel. The samples were assumed to be Newtonian fluids. Viscosity was measured on a digital rotary viscometer in a range of 0 to 80 °C. More significant difference between minimum and maximum values was found in case of diesel fuel in comparison with biodiesel fuel. Temperature dependence of both fuels was modeled using several mathematical models – polynomial, power and Gaussian equation. The Gaussian fit offers the best match between experimental and computed data. Description of viscosity behavior of fuels is critically important, e.g. when considering or calculating running efficiency and performance of combustion engines. The models proposed in this work may be used as a tool for precise prediction of rheological behavior of diesel-type fuels.
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KULCZYCKI, Andrzej, Wojciech DZIĘGIELEWSKI, and Dariusz OZIMINA. "THE INFLUENCE OF THE CHEMICAL STRUCTURE OF SYNTHETIC HYDROCARBONS AND ALCOHOLS ON THE LUBRICITY OF CI ENGINE FUELS AND AVIATION FUELS." Tribologia 273, no. 3 (June 30, 2017): 91–100. http://dx.doi.org/10.5604/01.3001.0010.6140.
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The paper covers the mechanism of lubrication layer formation by fuels containing synthetic hydrocarbons and alcohols. Development of alternative fuels containing FAME, alcohols, and synthetic hydrocarbons has increased the interest in the mechanism of lubrication of fuelling systems parts. Fuel lubricity tests have been conducted using the HFRR and BOCLE testing rigs. Fuels under testing, both for CI engines and for aviation turbine ones, contained synthetic components: saturated hydrocarbons both of even and odd number of carbon atoms, and butanol, isomers. These components have been added to conventional fuels, such as diesel fuel and Jet A-1 fuel at the concentration of 0–20% (V/V). All fuels under testing contained commercially available lubricity improvers (carboxylic acid). Test results were analysed using model αi described in [L. 6, 7]. As a result of the analysis, it has been found that the liquid phase, which is a lubricating film, should contain agglomerates or molecular clusters responsible for the transport of energy introduced into lubricating film by electrons emitted from metal surface. The mechanism enabling a description of the effect of base fuel without lubricity improvers on efficiency of such additives has been suggested.
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Linnik, A. "Paulownia as power culture." Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 22, no. 92 (May 8, 2020): 19–22. http://dx.doi.org/10.32718/nvlvet-a9204.
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The interest for production of energy crops, which biomass may be used as renewable fuel have been grown in 70 years of last century after dramatically rising price of fossil fuels. The energy crops growing have been also stimulated by environmental factors and approval some International political initiatives, like White Paper for a Community Strategy and Action Plan and The Kyoto protocol. After some decreasing, the area of energy crops in EU and North America countries are stabilized. In Ukraine in the last few years there is a gradual increase of part of energy consumption of biopropellant from 1.3 % in 2008 to 3.4 % in 2018 in the general energy consumption of country. As the most widespread energy cultures biomass of that is used as a biopropellant come forward willow, saccharine sorghum and miscanthus. However, the last years industrial plantations of power direction appeared the paulownias taken under growing. This arboreal culture is mainly presented by the artificially shown out hybrid of Paulownia Clone in of Vitro 112®. Paulownia it quickly grows tree that for today occupies the first places for speeds of increase bio the masses, the not demanding to the agrotechnics growing proof to illnesses and wreckers is suitable for recultivation of exhausted and useless for the conduct of traditional agriculture of soils. It is characterized a softwood that successfully can be used also in furniture industry, green mass has high maintenance of albumen confronted with leguminous cultures. Bio mass of paulownia is suitable for the production of bioethanol (it is possible to get a to 0.5 ton of ethanol from a 1 ton of dry wood) and fuel preforms and пелет (power value 4211.1 kkal/kg). Next to that, a paulownia is a melliferous culture from honey the productivity 700 kg/hectare of ecological honey, as during growing does not require chemical treatments. A paulownia can be useful to 20–50 years. After each the offcutss, that is conducted at any time year with an interval in 4–8, a tree grows. At the proper supervision in 7 it is possible to get a 240–350 m³ of quality wood from 1 hectare. Taking into account the features of growing and power descriptions bio the masses of paulownia her growing will be rational with the aim of receipt of high-energy bio mass and commercial timber, and also as a melliferous culture.
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Тарасов, Валерий, Valery Tarasov, Анатолий Соболенко, and Anatoly Sobolenko. "Impact of performance properties of regenerated engine oil on marine diesel wear when it runs on different grades of fuel." Vestnik of Astrakhan State Technical University. Series: Marine engineering and technologies 2019, no. 4 (November 15, 2019): 71–81. http://dx.doi.org/10.24143/2073-1574-2019-4-71-81.
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The article focuses on studying the operational properties of regenerated engine oils in terms of the impact on the wear of friction units of the trunk diesel engine when it works on the fuel of different grades. There have been built generalized models of marine diesel parts wear on the basis of experimental studies. Diesel 2Ч10,5/13 was used for experiments. Wear was determined by the method of artificial bases and by weighting. Four groups of the main indicators
of fuels used on ships have been considered (depending on the quality indicator). The first group includes distillate fuels and low-viscosity marine fuel which is close in its characteristics to foreign fuels. The second group includes motor fuel, naval fuel oil and export fuels (medium viscosity fuels). The third group presents high-viscosity marine fuel; the fourth group - fuels made from the remains of oil refining. The description of the generalized model of details wear of the tested diesel engine was carried out by a polynomial of the second order. To obtain the model, a non-position plan was chosen for three test variables: concentration of additives in oil, a fuel quality factor and a level of diesel forcing. The superposition of the hypersurfaces of the response of wear functions
of the internal combustion engine with diesel boosting factors at zero, lower, and upper levels with visualizing the effect on engine wear parameters depending on the additives concentration and quality of the fuel used in testing regenerated engine oil has been illustrated. Verification of the model's adequacy has proved that the model is adequate for machines with average effective pressure and a wide range of fuel grades. There has been given the possibility of using the obtained model to estimate the wear value at different values of parametric factors
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Smyshlyaeva, K. I., N. K. Kondrasheva, and V. A. Rudko. "Description of the stability of residual marine fuel using ternary phase diagrams and SARA analysis." E3S Web of Conferences 266 (2021): 02006. http://dx.doi.org/10.1051/e3sconf/202126602006.
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The results of the analysis of the properties of components of residual marine fuels (RMF) are described. The stability areas of marine fuels are determined using ternary phase diagrams VisRes - ULSD – LGOCC, Asphalt – ULSD – LCGO, Asphalt – ULSD – LGODC. The graphic method for determining the stability of A.B. Stankiewicz based on SARA analysis is used to describe the stability of RMF on the basis of VisRes - ULSD – LGOCC. The areas of stability, instability, and metastability of marine fuel are presented on the graph according to the Stankiewicz method, which can be used to predict the stability of RMF.
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Ciupek, Bartosz, Rafał Urbaniak, and Karolina Perz. "Analysis of technical parameters of black coals used in low–power boilers." AUTOBUSY – Technika, Eksploatacja, Systemy Transportowe 19, no. 12 (December 31, 2018): 386–89. http://dx.doi.org/10.24136/atest.2018.418.
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The article presents the results of technical analysis of black coals available in retail sales in Poland. A comprehensive list of fuel technical parameters and analysis of the possibilities of their use in low-power boilers was supported by the experience of the authors of the study. A thorough analysis of technical parameters of fuels concerned basic thermodynamic parameters of fuels responsible for the quality of thermal processes occurring in boilers. The collected data is presented in a uniform description of the current state of the sold fuels. In the last point, the researchers were looking at the technical aspects of the fuels offered in relation to the existing emission standard for low-power boilers.
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Serdyukova, E. Yu, Yu V. Kozhevnikova, A. A. Perminova, and L. R. Galikeeva. "Possibility of Liquid Biocomponent Usage in the Production of Commercial Diesel Fuel." Chemistry and Technology of Fuels and Oils 630, no. 2 (2022): 3–7. http://dx.doi.org/10.32935/0023-1169-2022-630-2-3-7.
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The article presents a description of the technique for compounding petroleum diesel fuel and a fraction of 180-240°C obtained from a liquid bioproduct of pyrolysis of plant materials. The physicochemical properties and group chemical composition of the fraction of plant origin have been studied. The results of the physicochemical properties of the resulting mixtures of diesel fuel are presented. Permissible concentrations of the biocomponent in the preparation of mixed biodiesel fuels have been established.
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Lönartz, Mara I., Jenna Poonoosamy, Yuankai Yang, Naila Ait-Mouheb, Guido Deissmann, and Dirk Bosbach. "Deciphering porosity clogging at barrier interfaces in deep geological repositories for radioactive waste." Safety of Nuclear Waste Disposal 1 (November 10, 2021): 181–82. http://dx.doi.org/10.5194/sand-1-181-2021.
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Abstract. The disposal of spent nuclear fuels and high-level radioactive wastes in deep geological repositories represents one of the greatest scientific-technical and societal challenges of our times. Most disposal concepts rely on a multibarrier system, consisting of a combination of engineered materials, geotechnical and geological barriers to provide a safe containment of the radioactive waste to protect humans and the environment against dangers arising from ionizing radiation. A reliable safety assessment of a deep geological repository over assessment time scales of several 100 000 years requires a profound and comprehensive understanding of the complex coupled physical (thermal, hydraulic, mechanical), chemical and biogeochemical (THM/CB) processes that govern the long-term evolution of the repository system. As a result of thermal and chemical gradients at the interfaces of different components and materials of the multi-barrier system (e.g. interfaces between metallic waste containers and bentonite backfill or between structural concrete and clay host rock), mineral dissolution and precipitation reactions are promoted; thus the (local) porosity, the volume filled with gas and/or water, can increase or decrease leading to changes in the macroscopic transport properties of the respective media. Although a reduction of the porosity (porosity clogging) appears to be desirable to inhibit radionuclide migration, it can also be detrimental, particularly in the case of gas pressure build-up due to canister corrosion or bacterial activity. So far, porosity clogging at barrier interfaces and associated consequences on solute or gas transport remain poorly understood; currently used mathematical descriptions of porosity clogging in reactive transport codes usually fail to capture respective experimental observations (Chagneau et al., 2015; Deng et al., 2021). In this context, we are developing a “lab-on-a-chip” set-up, which combines time lapse optical microscopy imaging and in operando Raman spectroscopy (Poonoosamy et al., 2019, 2020) to determine (i) whether complete clogging is possible and permanent, (ii) which parameters control the porosity clogging and (iii) which changes in transport properties of porous media are induced due to porosity clogging. Our approach comprises micronized counterdiffusion experiments with in situ visualization and monitoring of the evolution of mineralogy and microstructure/pore architecture with time. Complementary pore scale modelling will be used to derive key relationships that describe changes in transport properties due to mineral precipitation-induced porosity clogging. This approach will help to improve reactive transport codes and their predictive capabilities thus enhancing confidence and reduce uncertainties in long-term predictions, leading to more realistic descriptions of the evolution of complex repository systems.
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Dunaev, Anatoliy V., Aleksandr E. Lomovskikh, Igor’ F. Pustovoy, and Aleksandr S. Sayapin. "APPROBATED IMPROVEMENT OF THE SERVICE OF AUTOMOTIVE ENGINES." Tekhnicheskiy servis mashin 1, no. 142 (January 2021): 24–33. http://dx.doi.org/10.22314/2618-8287-2020-59-1-24-33.
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The need to increase the service life, efficiency and environmental friendliness of automotive engines leads to innovations in their maintenance and repair. Fuels are modified by mechanic-chemistry, hydrodynamic and acoustic cavitation, triboelectrization, and joint application of these methods. The most effective activators are described by Yu. V. Vorob’yov. (Research purpose) The research purpose is in summarizing the results of tests of activators by Yu. I. Vorobyov, identifying the features of their modification of motor fuels and outlining measures to ensure their stable operation in different internal combustion engines. (Materials and methods) The article presents the description of motor fuel activators under patents of the Russian Federation No. 2411074, 2550203, 2592801 and the results of their tests on KamAZ-740, ZMZ-406, YAMZ-236, UMZ-412 engines with fuels, with water-fuel emulsion, conducted at the Air Force Academy named after Professor N. E. Zhukovsky and Yu. A. Gagarin. (Results and discussion) Authors assumed from the analysis of the design of the activators by Yu. V. Vorobyov and the efficiency of their work, that their modification of fuels, rapeseed oil, alcohols and waters occurs first by mechanical-chemistry, then by cavitation, and finally by mechanical-chemistry. The effectiveness of the activator was confirmed by bench and operational tests to reduce fuel consumption by 21.3-31.9 percent, 80 pairs of chromatograms and chemmotology of modified liquids, the irreversibility and enhancement of fuel modification in storage, and other unusual properties of various activated liquids. (Conclusions) The effectiveness of the activator in increasing the caloric content of motor fuels by 26-30 percent and reducing their consumption by 21.3-31.9 percent is ensured by optimizing its design for different liquid consumption in it and anti-erosion materials. However, the activator requires resource and load tests on gasoline and diesel engines, testing for modification of oils and motor oils, tests at gas stations.
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Beavis, Nicholas J., Salah S. Ibrahim, and Weeratunge Malalasekera. "Impingement characteristics of an early injection gasoline direct injection engine: A numerical study." International Journal of Engine Research 18, no. 4 (August 19, 2016): 378–93. http://dx.doi.org/10.1177/1468087416663325.
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This article describes the use of a Lagrangian discrete droplet model to evaluate the liquid fuel impingement characteristics on the internal surfaces of an early injection gasoline direct injection engine. This study focuses on fuel impingement on the intake valve and cylinder liner between start of injection and 20° after start of injection using both a single- and a multi-component fuels. The single-component fuel used was iso-octane and the multi-component fuel contained fractions of iso-pentane, iso-octane and n-decane to represent the light, medium and heavy fuel fractions of gasoline, respectively. A detailed description of the impingement and liquid film modelling approach is also provided. Fuel properties, wall surface temperature and droplet Weber number and Laplace number were used to quantify the impingement regime for different fuel fractions and correlated well with the predicted onset of liquid film formation. Evidence of film stripping was seen from the liquid film formed on the side of the intake valve head with subsequent ejected droplets being a likely source of unburned hydrocarbons and particulate matter emissions. Differences in impingement location and subsequent location of liquid film formation were also observed between single- and multi-component fuels. A qualitative comparison with experimental cylinder liner impingement data showed the model to well predict the timing and positioning of the liner fuel impingement.
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Lanotte, Alfredo, Vincenzo De Bellis, and Enrica Malfi. "Potential of hydrogen addition to natural gas or ammonia as a solution towards low- or zero-carbon fuel for the supply of a small turbocharged SI engine." E3S Web of Conferences 312 (2021): 07022. http://dx.doi.org/10.1051/e3sconf/202131207022.
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Nowadays there is an increasing interest in carbon-free fuels such as ammonia and hydrogen. Those fuels, on one hand, allow to drastically reduce CO2 emissions, helping to comply with the increasingly stringent emission regulations, and, on the other hand, could lead to possible advantages in performances if blended with conventional fuels. In this regard, this work focuses on the 1D numerical study of an internal combustion engine supplied with different fuels: pure gasoline, and blends of methane-hydrogen and ammonia-hydrogen. The analyses are carried out with reference to a downsized turbocharged two-cylinder engine working in an operating point representative of engine operations along WLTC, namely 1800 rpm and 9.4 bar of BMEP. To evaluate the potential of methane-hydrogen and ammonia-hydrogen blends, a parametric study is performed. The varied parameters are air/fuel proportions (from 1 up to 2) and the hydrogen fraction over the total fuel. Hydrogen volume percentages up to 60% are considered both in the case of methane-hydrogen and ammonia-hydrogen blends. Model predictive capabilities are enhanced through a refined treatment of the laminar flame speed and chemistry of the end gas to improve the description of the combustion process and knock phenomenon, respectively. After the model validation under pure gasoline supply, numerical analyses allowed to estimate the benefits and drawbacks of considered alternative fuels in terms of efficiency, carbon monoxide, and pollutant emissions.
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Lihanov, V. A., and O. P. Lopatin. "Indication of the working process of the tractor diesel working on natural gas and alcohols." Traktory i sel hozmashiny 85, no. 4 (August 15, 2018): 18–25. http://dx.doi.org/10.17816/0321-4443-66371.
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The article deals with the use of natural gas and alcohol-fuel emulsions as an alternative fuel for tractor diesel. A distinctive feature of the processes of mixture formation and combustion in a diesel operating on natural gas with a burning portion of diesel fuel, and alcohol-fuel emulsions, will be compared with the diesel process heterogeneity of the fuel mixture in terms of cylinder volume, there is a completely different fuel evaporation and no coincidence in time of the processes of formation of fuel-air mixture and its combustion. Consequently, the use of alternative fuels with different chemical composition and local conditions leads to distinctive indicators of the combustion process. Therefore, for the scientific representation of the actual picture of the combustion process of diesel running on natural gas and alcohol-fuel emulsions, the indexing of its working process and a detailed description of the combustion process is carried out. At the same time, for the indexing of the diesel working process, the composition of alternative fuel was used when working on natural gas: gas-80 %, the ignition portion of diesel fuel-20 %; when working on alcohol-fuel emulsions: alcohol (methanol or ethanol) - 25 %, detergent-dispersing additive succinimide C-5A - 0,5 %, water - 7 %, diesel fuel - 67,5 %. As a result of the experimental studies, the dependences of the influence of the 4F 11,0/12,5 diesel modes on natural gas, natural gas with different degrees of exhaust gas recirculation (used to reduce the content of nitrogen oxides in the exhaust gases), methanol and ethanol fuel emulsions on the combustion process were established. The optimal values of the combustion process parameters during the operation of the diesel engine on alternative fuels of these compositions are determined.
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Pessina, Valentina, and Massimo Borghi. "Effect of Lagrangian-phase Modelling on Charge Stratification and Spatial Distribution of Threshold Soot Index for Toluene Reference Fuel Surrogates." E3S Web of Conferences 312 (2021): 07007. http://dx.doi.org/10.1051/e3sconf/202131207007.
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Nowadays, soot emissions are one of the major concerns in Direct Injection Spark Ignition engines. Soot prediction models can be computationally expensive, especially when particle mass, number, and size distribution are to be forecast. While soot formation heavily depends on the chemical and physical characteristics of the fuel, the simulation of the exact composition of a real gasoline is computationally unfeasible. Thus, it is essential to find simplified yet representative pathways to reduce the computational cost of the simulations. On the one hand, the a-priori investigation of the factors influencing particulate onset can be a simplified approach to compare different solutions and strategies with much cheaper costs than the modelling of soot formation and oxidation mechanisms. On the other hand, the use of surrogate fuels is a practical approach to cope with the fuel chemical nature. Although they poorly mimic the evaporation properties of a real gasoline, Toluene Reference Fuels are broadly adopted to match combustion relevant properties of the real fuels. In this study, the spatial distribution of the Threshold Soot Index in the fluid domain is investigated for three surrogates characterized by an increasing content of toluene (0 mol%, 30 mol%, 60 mol%). The correlation between the sooting tendency and the fuel distribution in the combustion chamber before spark ignition time can provide useful preliminary indications, without spending the computational effort of the whole soot model multicycle resolution. In particular, two approaches for the lagrangian description of the injected fuel are investigated: a multicomponent approach and a single component one, this last driven by a high-fidelity lumped modelling of the surrogate properties for both liquid and vapor phase.
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Braun-Unkhoff, M., E. Goos, T. Kathrotia, T. Kick, C. Naumann, N. Slavinskaya, and U. Riedel. "The Importance of Detailed Chemical Mechanisms in Gas Turbine Combustion Simulations." Eurasian Chemico-Technological Journal 16, no. 2-3 (April 8, 2014): 179. http://dx.doi.org/10.18321/ectj182.
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<p>This paper – in memory of Jürgen Warnatz – summarizes selected recent papers of the Chemical Kinetics Group at the German Aerospace Center in Stuttgart. It shows the need for detailed chemical reaction mechanisms to understand practical combustion systems. A comprehensive description of combustion processes based on detailed mechanisms is especially important in the design of new gas turbine combustion chambers and in the optimization of existing ones to improve efficiency and to reduce pollutant emissions, with fuel-flexibility and load-flexibility ever becoming more important. Different aspects of combustion processes where detailed reaction mechanisms provide useful insights will be covered in this paper: Fuels (alternative jet fuels, biomass based fuels), pollutants (soot), diagnostics (chemiluminescence), and thermochemistry. Furthermore, the underlying thermodynamics inevitably connected with detailed reaction schemes will be addressed. Exemplified results will be presented clearly demonstrating the predictive capabilities of detailed reaction mechanisms to be explored in computational fluid dynamic simulations to further optimize technical combustion systems.</p>
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Yur, G., and E. Nosonova. "Study of the working process of a diesel engine with modified fuel." Journal of Physics: Conference Series 2131, no. 2 (December 1, 2021): 022073. http://dx.doi.org/10.1088/1742-6596/2131/2/022073.
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Abstract The research objective is to reduce specific fuel consumption and emissions of exhaust fume pollutants. Specifically treated (modified) fuel is used to comprehensively improve the economic and environmental performance of the diesel operation process. Fuel treatment was carried out at a pilot plant using the process of fuel gas cavitation. During processing, high-molecular fuel compounds were broken down and the fuel was saturated with gas-vapor bubbles. The description of the pilot unit is given. The characteristics of the base distillate and modified fuel are studied. A mathematical model and the numerical study results of the fuel droplet development containing vapor-gas bubbles are presented. An experimental study of the work process in a 10.5/12 H diesel engine single-cylinder compartment when operating on various fuels was carried out. Diesel tests have shown that when using modified fuel, the specific indicative fuel consumption has decreased by 5-7 per g / kWh, the exhaust gas temperature has decreased by 5-8 degrees, the concentration of nitrogen oxides in the exhaust fumes has decreased by 32-46 ppm, the concentration of total hydrocarbons has decreased by 9-14 ppm, the smoke content has decreased by 1.2-1.7 times.
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Borsuk, Grzegorz, Bolesław Dobrowolski, Grzegorz Nowosielski, Jacek Wydrych, and Jerzy Duda. "Numerical simulation of thermal-hydraulic processes in the riser chamber of installation for clinker production." Archives of Thermodynamics 37, no. 1 (March 1, 2016): 127–42. http://dx.doi.org/10.1515/aoter-2016-0009.
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AbstractClinker burning process has a decisive influence on energy consumption and the cost of cement production. A new problem is to use the process of decarbonization of alternative fuels from waste. These issues are particularly important in the introduction of a two-stage combustion of fuel in a rotary kiln without the typical reactor-decarbonizator. This work presents results of numerical studies on thermal-hydraulic phenomena in the riser chamber, which will be designed to burn fuel in the system where combustion air is supplied separately from the clinker cooler. The mathematical model is based on a combination of two methods of motion description: Euler description for the gas phase and Lagrange description for particles. Heat transfer between particles of raw material and gas was added to the numerical calculations. The main aim of the research was finding the correct fractional distribution of particles. For assumed particle distribution on the first stage of work, authors noted that all particles were carried away by the upper outlet to the preheater tower, what is not corresponding to the results of experimental studies. The obtained results of calculations can be the basis for further optimization of the design and operating conditions in the riser chamber with the implementation of the system.
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Mladenovic, Milica, Stevan Nemoda, Mirko Komatina, and Dragoljub Dakic. "Numerical simulation of non-conventional liquid fuels feeding in a bubbling fluidized bed combustor." Thermal Science 17, no. 4 (2013): 1163–79. http://dx.doi.org/10.2298/tsci121116007m.
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The paper deals with the development of mathematical models for detailed simulation of lateral jet penetration into the fluidized bed (FB), primarily from the aspect of feeding of gaseous and liquid fuels into FB furnaces. For that purpose a series of comparisons has been performed between the results of in-house developed procedure- fluid-porous medium numerical simulation of gaseous jet penetration into the fluidized bed, Fluent?s two-fluid Euler-Euler FB simulation model, and experimental results (from the literature) of gaseous jet penetration into the 2D FB. The calculation results, using both models, and experimental data are in good agreement. The developed simulation procedures of jet penetration into the FB are applied to the analysis of the effects, which are registered during the experiments on a fluidized pilot furnace with feeding of liquid waste fuels into the bed, and brief description of the experiments is also presented in the paper. Registered effect suggests that the water in the fuel improved mixing of fuel and oxidizer in the FB furnace, by increasing jet penetration into the FB due to sudden evaporation of water at the entry into the furnace. In order to clarify this effect, numerical simulations of jet penetration into the FB with three-phase systems: gas (fuel, oxidizer, and water vapour), bed particles and water, have been carried out.
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Faravelli, Tiziano, Alessio Frassoldati, Eliseo Ranzi, Miccio Francesco, and Miccio Michele. "Modeling Homogeneous Combustion in Bubbling Beds Burning Liquid Fuels." Journal of Energy Resources Technology 129, no. 1 (February 21, 2006): 33–41. http://dx.doi.org/10.1115/1.2424957.
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This paper introduces a model for the description of the homogeneous combustion of various fuels in fluidized bed combustors (FBC) at temperatures lower than the classical value for solid fuels, i.e., 850°C. The model construction is based on a key bubbling fluidized bed feature: A fuel-rich (endogenous) bubble is generated at the fuel injection point, travels inside the bed at constant pressure, and undergoes chemical conversion in the presence of mass transfer with the emulsion phase and of coalescence with air (exogenous) bubbles formed at the distributor and, possibly, with other endogenous bubbles. The model couples a fluid-dynamic submodel based on two-phase fluidization theory with a submodel of gas phase oxidation. To this end, the model development takes full advantage of a detailed chemical kinetic scheme, which includes both the low and high temperature mechanisms of hydrocarbon oxidation, and accounts for about 200 molecular and radical species involved in more than 5000 reactions. Simple hypotheses are made to set up and close mass balances for the various species as well as enthalpy balances in the bed. First, the conversion and oxidation of gaseous fuels (e.g., methane) were calculated as a test case for the model; then, n-dodecane was taken into consideration to give a simple representation of diesel fuel using a pure hydrocarbon. The model predictions qualitatively agree with some of the evidence from the experimental data reported in the literature. The fate of hydrocarbon species is extremely sensitive to temperature change and oxygen availability in the rising bubble. A preliminary model validation was attempted with results of experiments carried out on a prepilot, bubbling combustor fired by underbed injection of a diesel fuel. Specifically, the model results confirm that heat release both in the bed and in the freeboard is a function of bed temperature. At lower emulsion phase temperatures many combustible species leave the bed unburned, while post-combustion occurs after the bed and freeboard temperature considerably increases. This is a well-recognized undesirable feature from the viewpoint of practical application and emission control.
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Trueblood, Max B., Prem Lobo, Donald E. Hagen, Steven C. Achterberg, Wenyan Liu, and Philip D. Whitefield. "Application of a hygroscopicity tandem differential mobility analyzer for characterizing PM emissions in exhaust plumes from an aircraft engine burning conventional and alternative fuels." Atmospheric Chemistry and Physics 18, no. 23 (December 3, 2018): 17029–45. http://dx.doi.org/10.5194/acp-18-17029-2018.
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Abstract. In the last several decades, significant efforts have been directed toward better understanding the gaseous and particulate matter (PM) emissions from aircraft gas turbine engines. However, limited information is available on the hygroscopic properties of aircraft engine PM emissions which play an important role in the water absorption, airborne lifetime, obscuring effect, and detrimental health effects of these particles. This paper reports the description and detailed lab-based performance evaluation of a robust hygroscopicity tandem differential mobility analyzer (HTDMA) in terms of hygroscopic properties such as growth factor (GF) and the hygroscopicity parameter (κ). The HTDMA system was subsequently deployed during the Alternative Aviation Fuel EXperiment (AAFEX) II field campaign to measure the hygroscopic properties of aircraft engine PM emissions in the exhaust plumes from a CFM56-2C1 engine burning several types of fuels. The fuels used were conventional JP-8, tallow-based hydroprocessed esters and fatty acids (HEFA), Fischer–Tropsch, a blend of HEFA and JP-8, and Fischer–Tropsch doped with tetrahydrothiophene (an organosulfur compound). It was observed that GF and κ increased with fuel sulfur content and engine thrust condition, and decreased with increasing dry particle diameter. The highest GF and κ values were found in the smallest particles, typically those with diameters of 10 nm.
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Adamczyk, Wojciech Piotr, Grzegorz Kruczek, Ryszard Bialecki, and Grzegorz Przybyła. "Application of different numerical models capable to simulate combustion of alternative fuels in internal combustion engine." International Journal of Numerical Methods for Heat & Fluid Flow 30, no. 5 (August 22, 2019): 2517–34. http://dx.doi.org/10.1108/hff-03-2019-0268.
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Purpose The internal combustion engine operated on gaseous fuels shows great potential in terms of integration of the renewable and traditional sources for an effective solution for clean energy production challenge. Different fuel mixtures that can be used to power the engine are characterized by various combustion properties, which can affect its overall efficiency. The purpose of this paper is to provide reasonable answer, how the operation condition can change due to different fuel, without enormous cost of prototyping processes using physical models a digital model can be seen as promising technique. Design/methodology/approach Presented work discusses the application, and extensive description of two commercial codes Ansys Fluent and Forte for modeling stationary engine fueled by compressed natural gas (CNG) and biogas. To check the model accuracy, all carried out numerical results were compared against experimental data collected at in-house test rig of single cylinder four stroke engine. The impacts of tested gaseous fuel on the engine working conditions and emission levels were investigated. Findings Carried out simulations showed good agreement with experimental data for investigated cases. Application on numerical models give possibility to visualize flame front propagation and pollutant formation for tested fuels. The biogas fuel has shown the impaired early flame phase, which led to longer combustion, lower efficiency, power output, repeatability and in some cases higher HC and carbon monoxide (CO) emissions as a result of combustion during the exhaust stroke. Looking at the CO formation it was observed that it instantly accrue with flame front propagation as a result of methane oxidation, while for NOx formation revers effect was seen. Originality/value The application of new approach for modeling combustion process in stationary engines fueled by CNG and alternative biogas fuel has been discussed. The cons and pros of the Forte code in terms of its application for engine prototaping process has been discussed.
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Bell, R. C., T. W. Prete, and J. T. Stewart. "Specification, Development, and Testing of the FT8-2 Dry Low NOx Control System." Journal of Engineering for Gas Turbines and Power 118, no. 3 (July 1, 1996): 547–52. http://dx.doi.org/10.1115/1.2816682.
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This paper describes the specification, development, and testing of the FT8-2 Dry Low NOx control system, and how the lean burn process requires an integration of the control system and combustion hardware. The FT8-2 digital fuel control system was developed to achieve the precise multizone fuel metering of both gas and liquid fuels, the calculation of combustor air flow necessary to achieve Dry Low NOx and the traditional governing/limiting control loops necessary for safe, stable engine operation. The system design goals were accomplished by the concurrent development of software-based fuel metering algorithms and fuel metering hardware. The fuel metering hardware utilizes an all-electronic valve positioner, employing a combination of feedback and software to achieve closed-loop control of actual fuel flow. Extensive testing under actual gas flow conditions and closed-loop bench testing using a real time engine model and fuel system model was conducted to prove system operation and develop system transient response prior to installation on the test engine. The setup and results of the flow testing and closed-loop testing are described. The paper describes the control scheme used to apportion the gas fuel between combustion zones and how external conditions such as ambient temperature and fuel gas composition affect the apportionment. The paper concludes with a description of the control system installation in the engine test cell and a review of engine test results.
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Gu, Tianbao, Torsten Berning, and Chungen Yin. "Application of a New Statistical Model for the Description of Solid Fuel Decomposition in the Analysis of Artemisia apiacea Pyrolysis." Energies 14, no. 18 (September 14, 2021): 5789. http://dx.doi.org/10.3390/en14185789.
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Pyrolysis, one of the key thermochemical conversion technologies, is very promising to obtain char, oil and combustible gases from solid fuels. Kinetic modeling is a crucial method for the prediction of the solid conversion rate and analysis of the pyrolysis process. We recently developed a new statistical model for the universal description of solid fuel decomposition, which shows great potential in studying solid fuel pyrolysis. This paper demonstrates three essential applications of this new model in the analysis of Artemisia apiacea pyrolysis, i.e., identification of the conversion rate peak position, determination of the reaction mechanism, and evaluation of the kinetics. The results of the first application show a very good agreement with the experimental data. From the second application, the 3D diffusion-Jander reaction model is considered as the most suitable reaction mechanism for the description of Artemisia stem pyrolysis. The third application evaluates the kinetics of Artemisia stem pyrolysis. The evaluated kinetics vary with the conversion degree and heating rates, in which the activation energies and pre-exponential factors (i.e., lnA vs. Ea) show a linear relationship, regardless of the conversion and heating rates. Moreover, the prediction of the conversion rate using the obtained kinetics shows an excellent fit with the experimental data.
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Cancellieri, Dominique, Valérie Leroy-Cancellieri, Xavier Silvani, and Frédéric Morandini. "New experimental diagnostics in combustion of forest fuels: microscale appreciation for a macroscale approach." Natural Hazards and Earth System Sciences 18, no. 7 (July 16, 2018): 1957–68. http://dx.doi.org/10.5194/nhess-18-1957-2018.
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Abstract. In modelling the wildfire behaviour, good knowledge of the mechanisms and the kinetic parameters controlling the thermal decomposition of forest fuel is of great importance. The kinetic modelling is based on the mass-loss rate, which defines the mass-source term of combustible gases that supply the flames and influences the propagation of wildland fires. In this work, we investigated the thermal degradation of three different fuels using a multi-scale approach. Lab-scale experimental diagnostics such as thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), use of the cone calorimeter (CC) or Fire Propagation Apparatus (FPA) led to valuable results for modelling the thermal degradation of vegetal fuels and allowed several upgrades of pyrolysis models. However, this work remains beyond large-scale conditions of a wildland or forest fire. In an effort to elaborate on the kinetic models under realistic natural fire conditions, a mass-loss device specifically designed for the field scale has been developed. The paper presents primary results gained using this new device, during large-scale experiments of controlled fires. The mass-loss records obtained on a field scale highlight the influence of the chemical composition and the structure of plants. Indeed, two species with similar chemical and morphological characteristics exhibit similar mass-loss rates, whereas the third presents different thermal behaviour. The experimental data collected at a field scale led to a new insight about thermal degradation processes of natural fuel when compared to the kinetic laws established in TGA. These new results provide a global description of the kinetics of degradation of Mediterranean forest fuels. The results led to a proposed thermal degradation mechanism that has also been validated on a larger scale.
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Jasjfi, E. "Trends and Development of Petroleum Fuel Qualities in Indonesia." Scientific Contributions Oil and Gas 14, no. 2 (April 7, 2022): 59–67. http://dx.doi.org/10.29017/scog.14.2.890.
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Barths, H., C. Hasse, and N. Peters. "Computational fluid dynamics modelling of non-premixed combustion in direct injection diesel engines." International Journal of Engine Research 1, no. 3 (June 1, 2000): 249–67. http://dx.doi.org/10.1243/1468087001545164.
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An overview over flamelet modelling for turbulent non-premixed combustion is given. A short review of previous contributions to simulations of direct injection (DI) diesel engine combustion using the representative interactive flamelet concept is presented. A surrogate fuel consisting of 70 per cent (liquid volume) n-decane and 30 per cent α-methyl-naphthalene is experimentally compared to real diesel fuel. The resemblance of their physical and chemical properties is shown to result in very similar combustion and pollutant formation for both fuels. In order to account for variations of the scalar dissipation rate within the computational domain, a method using multiple flamelets, called the Eulerian particle flamelet model, is used. A strategy is described for subdividing the computational domain and assigning the resulting subdomains to different flamelet histories represented by Eulerian marker particles. Experiments conducted with an Audi DI diesel engine and diesel fuel are compared to simulations using the surrogate fuel. The use of multiple flamelets, each having a different history, significantly improves the description of the ignition phase, leading to a better prediction of pressure, heat release and exhaust emissions of soot and NOx. The effect of the number of flamelet particles on the predictions is discussed.
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STEPANENKO, Denys, and Zbigniew KNEBA. "Thermodynamic modeling of combustion process of the internal combustion engines – an overview." Combustion Engines 178, no. 3 (July 1, 2019): 27–37. http://dx.doi.org/10.19206/ce-2019-306.
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The mathematical description of combustion process in the internal combustion engines is a very difficult task, due to the variety of phenomena that occurring in the engine from the moment when the fuel-air mixture ignites up to the moment when intake and exhaust valves beginning open. Modeling of the combustion process plays an important role in the engine simulation, which allows to predict in-cylinder pressure during the combustion, engine performance and environmental impact with high accuracy. The toxic emissions, which appears as a result of fuels combustion, are one of the main environmental problem and as a result the air pollutant regulations are increasingly stringent, what makes the investigation of the combustion process to be a relevant task.
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Grishin, N. N., and V. V. Sereda. "Basic Theoretical Thesises of Chemmotology." World of Oil products the Oil Companies Bulletin 05 (2020): 54–59. http://dx.doi.org/10.32758/2071-5951-2020-0-5-54-59.
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Toward the end of the 20th century fundamental theories of oxidation, combustion, friction, deterioration, corrosion and others were adapted to chemmotology systems: proposed an oscillatory-homogenous theory of the formation of free radicals in hydrocarbonated nature; demonstrated unsuitability of “physical” model of combustion for a description of working processes of engines; worked out a theory of boundary processes of grease and friction as applied with conjugate details; worked out the general patterns of tribochemical reactions in lubricant nature; developed the basis of theory of physico-chemical mechanics of pseudocolloidal systems. At the present moment established the general patterns of the effect of quality of combustion and composition of fuel during the period of delay of ignition, speed and volume of burning of hydrocarbons ; worked out a concept of quasiciliary formation of fuels, defining their condition of metastable state; proposed mechanism of abnormally - fast internally flaming gasification of dispersing carbohydrate ; worked out an electro-kinetical model of quality state of engine oils in static and dynamic conditions and many others . Introduction of relevant theoretical basis will provide quantitative description of chemotological processes.
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Ryms, Michał, Katarzyna Januszewicz, Witold M. Lewandowski, and Ewa Klugmann-Radziemska. "Pyrolysis Process of Whole Waste Tires as A Biomass Energy Recycling / Piroliza Opon Samochodowych Jako Energetyczny Recykling Biomasy." Ecological Chemistry and Engineering S 20, no. 1 (March 1, 2013): 93–107. http://dx.doi.org/10.2478/eces-2013-0007.
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Abstract The article is devoted to the description of material recycling of whole waste tires, including a new method of pyrolysis process, resulting in the final products: technically oil fractions (rubber plasticizer of rubber compounds) or diesel fuels (light, medium and heavy), activated carbon, gas fuel and steel scrap. Operational and performance tests of the first version of the pilot plant, consisting of three contributions cooperating with one pyrolytic reactor confirmed that this technology is applicable but has still some flaws and errors, both structural and technological. Usually such errors in the first test of technology development cannot be avoided. This paper describes: pyrolysis processes which occurs in the pilot plant, protected by a patent application design of continuously working prototype installation for recycling of tire and identifies future directions of research in this field
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Ekmanis, J., E. Tomsons, and N. Zeltiņš. "High-Temperature Nuclear Reactors (Overview. Part 1) / Augstas Temperatūras Kodolreaktori (Pārskata raksts) 1. daļa." Latvian Journal of Physics and Technical Sciences 50, no. 1 (February 1, 2013): 47–57. http://dx.doi.org/10.2478/lpts-2013-0002.
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At the Generation IV International Forum (GIF) of 2001 the measures were approved which are necessary for the development of future generation nuclear reactors (NRs). Six best high-temperature NR technologies were selected, with the main criteria being the safe and economically profitable operation, long-term use, protection against the employment of nuclear material for military purposes and terroristic attacks as well as technologies of fuel close cycle in order to increase the amount of fission material and decrease the amount of highly radioactive waste. In four of the technologies, apart from electricity production also hydrogen is obtained. Part 1 presents a generalized description of the high-temperature NRs, their comparative characteristics and history, with the stopped and operational HTNRs outlined. The properties of different type nuclear fuels are described in detail
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Spets, Jukka Pekka, Maunu Kuosa, Tom Granström, Yohannes Kiros, Jyri Rantanen, Markku J. Lampinen, and Kari Saari. "Production of Glucose by Starch and Cellulose Acid Hydrolysis and its Use as a Fuel in Low-Temperature Direct-Mode Fuel Cells." Materials Science Forum 638-642 (January 2010): 1164–69. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.1164.
Full textAbstract:
The use of glucose, which is produced from the acid hydrolysis of starch and cellulose, is studied as a fuel in a low-temperature direct-mode fuel cell (LTDMFC) with an alkaline electrolyte. Glucose is regarded as being as good a fuel as bioethanol, because both the fuels give 2 electrons per molecule in the fuel cell without carbonisation problems. However, glucose can be produced with fewer processing stages from starch and cellulose than can bioethanol. In the LTDMFC the fuel and the electrolyte are mixed with each other and the fuel cell is equipped only with metal catalysts. Cellulose as a fuel is of great importance because the fuel for the energy production is not taken from food production. A description of an acid hydrolysis method for starch and cellulose is presented. Values for glucose concentrations in each hydrolysate are analysed by means of a chromatographic method. Each glucose hydrolysate was made alkaline by adding of potassium hydroxide before feed in the fuel cell. Polarisation curves were measured, and they were found to produce lower current density values when compared to earlier tests with pure glucose. The Coulombic efficiency of pure glucose electrochemical oxidation in LTDMFC, which was calculated from a ratio of detected current capacity (As) to the maximum current capacity with the release of two electrons per molecule, was also found to be very low. Concerning the hydrolysates, the glucose concentrations were found to have values that were too low when compared to the earlier tests with pure glucose in a concentration of 1 M. The further development demands for the system under consideration are indicated. The concentration of glucose in the hydrolysate is essential to achieve high enough current density values in the LTDMFC.
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ARRIETA-SANAGUSTÍN, J., A. L. SÁNCHEZ, A. LIÑÁN, and F. A. WILLIAMS. "Sheath vaporization of a monodisperse fuel-spray jet." Journal of Fluid Mechanics 675 (March 17, 2011): 435–64. http://dx.doi.org/10.1017/s0022112011000255.
Full textAbstract:
The group vaporization of a monodisperse fuel-spray jet discharging into a hot coflowing gaseous stream is investigated for steady flow by numerical and asymptotic methods with a two-continua formulation used for the description of the gas and liquid phases. The jet is assumed to be slender and laminar, as occurs when the Reynolds number is moderately large, so that the boundary-layer form of the conservation equations can be employed in the analysis. Two dimensionless parameters are found to control the flow structure, namely the spray dilution parameter λ, defined as the mass of liquid fuel per unit mass of gas in the spray stream, and the group vaporization parameter ϵ, defined as the ratio of the characteristic time of spray evolution due to droplet vaporization to the characteristic diffusion time across the jet. It is observed that, for the small values of ϵ often encountered in applications, vaporization occurs only in a thin layer separating the spray from the outer droplet-free stream. This regime of sheath vaporization, which is controlled by heat conduction, is amenable to a simplified asymptotic description, independent of ϵ, in which the location of the vaporization layer is determined numerically as a free boundary in a parabolic problem involving matching of the separate solutions in the external streams, with appropriate jump conditions obtained from analysis of the quasi-steady vaporization front. Separate consideration of dilute and dense sprays, corresponding, respectively, to the asymptotic limits λ ≪ 1 and λ ≫ 1, enables simplified descriptions to be obtained for the different flow variables, including explicit analytic expressions for the spray penetration distance.
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Shotbolt-Brown, Joanna, David W. F. Hunter, and Jackie Aislabie. "Isolation and description of carbazole-degrading bacteria." Canadian Journal of Microbiology 42, no. 1 (January 1, 1996): 79–82. http://dx.doi.org/10.1139/m96-012.
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Carbazole is a nitrogen hetrocyclic compound associated with fossil fuels and their products. Enrichment cultures were established to isolate bacteria able to degrade carbazole and a plate assay was developed to select carbazole-degrading microorganisms from the enrichments. Three different bacterial isolates capable of mineralizing carbazole were obtained. No intermediates of carbazole degradation were detected. The bacteria had a limited substrate specificity; all used benzoate for growth but were unable to utilize the analogues of carbazole, fluorene, or dibenzothiophene.Key words: carbazole, biodegradation, bacteria.
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Ouyang, Wenhong, Wensheng Lai, Jiahao Li, Jianbo Liu, and Baixin Liu. "Atomic Simulations of U-Mo under Irradiation: A New Angular Dependent Potential." Metals 11, no. 7 (June 24, 2021): 1018. http://dx.doi.org/10.3390/met11071018.
Full textAbstract:
Uranium-Molybdenum alloy has been a promising option in the production of metallic nuclear fuels, where the introduction of Molybdenum enhances mechanical properties, corrosion resistance, and dimensional stability of fuel components. Meanwhile, few potential options for molecular dynamics simulations of U and its alloys have been reported due to the difficulty in the description of the directional effects within atomic interactions, mainly induced by itinerant f-electron behaviors. In the present study, a new angular dependent potential formalism proposed by the author’s group has been further applied to the description of the U-Mo systems, which has achieved a moderately well reproduction of macroscopic properties such as lattice constants and elastic constants of reference phases. Moreover, the potential has been further improved to more accurately describe the threshold displacement energy surface at intermediate and short atomic distances. Simulations of primary radiation damage in solid solutions of the U-Mo system have also been carried out and an uplift in the residual defect population has been observed when the Mo content decreases to around 5 wt.%, which corroborates the negative role of local Mo depletion in mitigation of irradiation damage and consequent swelling behavior.