A Comprehensive Kinetics Library for Simulating the Combustion of Automotive Fuels

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Chitralkumar V. Naik ◽  
Karthik V. Puduppakkam ◽  
Ellen Meeks
Keyword(s):  
Carbon Number ◽  
Chemical Properties ◽  
Estimation Methods ◽  
Specific Rate ◽  
Fuel Component ◽  
Number Range ◽  
Gaseous Fuels ◽  
Design Concepts ◽  
Reduction Methods ◽  
Fuel Components

We have developed a surrogate blending methodology to identify surrogates with a desired degree of complexity. Along with estimation methods for various physical and chemical properties for fuel blends, we have assembled and developed a rich library of over 60 fuel components. The components cover a carbon number range from 1 to 20, and chemical classes including linear and branched alkanes, olefins, aromatics with one and two rings, alcohols, esters, and ethers. With these, surrogates can be formulated to represent most gasoline, diesel, gaseous fuels, renewable fuels, and several additives. As part of the library, we have assembled self-consistent and detailed reaction mechanisms for all the components, as well as for emissions including NOx and polycyclic aromatic hydrocarbons and a detailed soot-surface mechanism. An extensive validation suite has been used to improve the kinetics database such that good predictions and agreement to data are achieved for the fuel components and fuel-component blends, within experimental uncertainties. This effectively eliminates the need to tune specific rate parameters when employing the kinetics mechanisms in combustion simulations. For engine simulations, the master mechanisms have been reduced using a combination of available reduction methods while strictly controlling the error tolerances for targeted predictions. This approach has resulted in small mechanisms for efficiently incorporating the validated kinetics into computational fluid dynamics (CFD) applications. The surrogate formulation methodology, the comprehensive fuel library, and mechanism reduction strategies suggested in this work allow the use of CFD to explore design concepts and fuel effects in engines with reliable predictions.

A Comprehensive Kinetics Library for Simulating the Combustion of Automotive Fuels

2018 ◽  
Author(s):  
Chitralkumar V. Naik ◽  
Karthik V. Puduppakkam ◽  
Ellen Meeks
Keyword(s):  
Molecular Weight ◽  
Average Molecular Weight ◽  
Carbon Number ◽  
Diagnostic Methods ◽  
Specific Rate ◽  
Number Range ◽  
Wide Range ◽  
Reduction Methods ◽  
Ignition Quality ◽  
Fuel Components

With advanced engines pushing the limits of fuel efficiency, rapid development and improvement of engines increasingly rely on insights from simulations. Reliable simulations require fuel models that consist of a fuel surrogate and its kinetic mechanism. As complexity and sources of fuels vary, a good surrogate needs to be tailored for the specific test fuel. A simple surrogate, typically consisting of 1 to 3 components, can match a single property of the real fuel, such as ignition quality or average molecular weight. More complex surrogates with 4 to 7 components can capture many properties simultaneously. While simple surrogates are good for estimating ignition in engines they require some compensation for the mismatch of the fuels’s physical properties. Complex surrogates can be used to directly represent real fuels in both laboratory experiments and simulations. We have developed a surrogate blending methodology to identify surrogates with a desired degree of complexity. This involves methods that estimate properties for fuel blends, including ignition quality, sooting propensity, distillation curve, as well as other physical and chemical properties that are important to combustion behavior in simulations. We have assembled and developed a rich library of over 60 fuel components from which we can formulate surrogates to represent most gasoline, diesel, gaseous fuels, renewable fuels, and several additives. The components cover a carbon number range from 1 to 20, and chemical classes including linear and branched alkanes, olefins, aromatics with one and two rings, alcohols, esters, and ethers. As part of the library, we have assembled self-consistent and detailed reaction mechanisms for all the components. The mechanisms also include comprehensive NOx creation and destruction pathways, molecular weight growth kinetics leading to the formation of polycyclic aromatic hydrocarbons (PAH), and a detailed soot-surface mechanism. The mechanisms have been validated extensively using over 500 published sets of experimental kinetics data from a wide range of facilities and diagnostic methods. Over the past decade, the validation suite has been used to improve the kinetics database such that good predictions and agreement to data are achieved for the fuel components and fuel-component blends, within experimental uncertainties. This effectively eliminates the need to tune specific rate parameters when employing the kinetics mechanisms in combustion simulations. For engine simulations, the master mechanisms have been reduced using a combination of available reduction methods while strictly controlling the error tolerances for targeted predictions. These include several directed relation graph (DRG) based methods and sensitivity analysis. Iteratively using these reduction methods has resulted in small mechanisms for efficiently incorporating the validated kinetics into computational fluid dynamics (CFD) applications. The surrogate formulation methodology, the comprehensive fuel library, and mechanism reduction strategies suggested in this work allow the use of CFD to explore design concepts and fuel effects in engines with reliable predictions.

scholarly journals An Influence of Correction of the Ignition Advance Angle on the Combustion Process in SI Engine Fuelled by LPG with the Addition of DME

2019 ◽  
Vol 26 (4) ◽  
pp. 285-292
Author(s):  
Grzegorz Kubica ◽  
Paweł Marzec
Keyword(s):  
Full Range ◽  
Combustion Process ◽  
Experimental Tests ◽  
Point Of View ◽  
Si Engine ◽  
Fuel Component ◽  
Gaseous Fuels ◽  
Basic Engine ◽  
Positive Effect ◽  
Fuel Components

AbstractThe paper presents the results of tests of the SI engine fuelled by LPG with the addition of DME in the form of a mixture of gaseous fuels. Experimental tests were carried out on a chassis dynamometer in the full range of engine loads, at a fixed rotational speed: 2000, 2500 and 3000 rpm. The use of dimethyl ether (DME) as a fuel component makes it possible to exploit its important advantages. DME can be produced as a renewable fuel, which is important from the point of view of ecology. Another important fact is the presence of oxygen in this fuel, which has a positive effect on the engine volumetric efficiency. During the tests, the ignition timing was also adjusted due to the very good DME flammability. Two additional correction levels were applied, increasing the ignition advance by 3 and 6 CA degrees, compared to the factory settings of the driver. The analysis of the obtained results allowed determining the dependence of the basic engine parameters, in the function of the correction of ignition advance angle. In the summary, attention was also paid to the possibility of determining corrected maps of the ignition advance angle taking into account the variable proportions of fuel components.

scholarly journals A potential antiviral and food-derived healthy ingredient: Resveratrol

2021 ◽  
Vol 7 (1) ◽  
pp. 54-63
Author(s):  
Ayla Arslaner ◽  
Zehra Türkoğlu
Keyword(s):  
Carbon Number ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Food Ingredient ◽  
Beneficial Effects ◽  
Antiviral Effects ◽  
Natural Polyphenol ◽  
Physical And Chemical ◽  
And Chemical Properties

Polyphenols are the secondary metabolites of plants and has an important role in human nutrition as the leading antioxidants. According to the carbon number-based classification of polyphenols, resveratrol is a natural polyphenol in the stilbene group with antioxidant and anticarcinogenic effects. Its beneficial effects on cardiovascular diseases have also been reported. It was first identified in 1940 and has recently gained importance especially in medicine and pharmacy. Researchers have carried out various studies on resveratrol and its time-honored use in traditional eastern medicine has been reported. Resveratrol is a food ingredient that has the potential to be used in the treatment of various diseases, but also has antiviral effects. The study focuses on resveratrol’s physical and chemical properties, effects on health, antiviral effects and use in foods as a functional component.

scholarly journals Using advanced mass spectrometry techniques to fully characterize atmospheric organic carbon: current capabilities and remaining gaps

2017 ◽  
Vol 200 ◽  
pp. 579-598 ◽  
Author(s):  
G. Isaacman-VanWertz ◽  
P. Massoli ◽  
R. E. O’Brien ◽  
J. B. Nowak ◽  
M. R. Canagaratna ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Structural Information ◽  
Carbon Number ◽  
Chemical Properties ◽  
Oxidation Products ◽  
Particle Phase ◽  
Atmospheric Measurements ◽  
Mass Spectrometers ◽  
Phase Measurements ◽  
New Generation

Organic compounds in the atmosphere vary widely in their molecular composition and chemical properties, so no single instrument can reasonably measure the entire range of ambient compounds. Over the past decade, a new generation of in situ, field-deployable mass spectrometers has dramatically improved our ability to detect, identify, and quantify these organic compounds, but no systematic approach has been developed to assess the extent to which currently available tools capture the entire space of chemical identity and properties that is expected in the atmosphere. Reduced-parameter frameworks that have been developed to describe atmospheric mixtures are exploited here to characterize the range of chemical properties accessed by a suite of instruments. Multiple chemical spaces (e.g. oxidation state of carbon vs. volatility, and oxygen number vs. carbon number) were populated with ions measured by several mass spectrometers, with gas- and particle-phase α-pinene oxidation products serving as the test mixture of organic compounds. Few gaps are observed in the coverage of the parameter spaces by the instruments employed in this work, though the full extent to which comprehensive measurement was achieved is difficult to assess due to uncertainty in the composition of the mixture. Overlaps between individual ions and regions in parameter space were identified, both between gas- and particle-phase measurements, and within each phase. These overlaps were conservatively found to account for little (<10%) of the measured mass. However, challenges in identifying overlaps and in accurately converting molecular formulas into chemical properties (such as volatility or reactivity) highlight a continued need to incorporate structural information into atmospheric measurements.

scholarly journals Future-Oriented Experimental Characterization of 3D Printed and Conventional Elastomers Based on Their Swelling Behavior

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4402
Author(s):  
Klara Loos ◽  
Vivianne Marie Bruère ◽  
Benedikt Demmel ◽  
Yvonne Ilmberger ◽  
Alexander Lion ◽  
...  
Keyword(s):  
Tensile Tests ◽  
Swelling Behavior ◽  
Uniaxial Tensile ◽  
Stress And Strain ◽  
Experimental Characterization ◽  
Synthetic Fuels ◽  
Fuel Component ◽  
3D Printed ◽  
Fuel Components

The present study investigates different elastomers with regard to their behavior towards liquids such as moisture, fuels, or fuel components. First, four additively manufactured materials are examined in detail with respect to their swelling in the fuel component toluene as well as in water. The chemical nature of the materials is elucidated by means of infrared spectroscopy. The experimentally derived absorption curves of the materials in the liquids are described mathematically using Fick’s diffusion law. The mechanical behavior is determined by uniaxial tensile tests, which are evaluated on the basis of stress and strain at break. The results of the study allow for deriving valuable recommendations regarding the printing process and postprocessing. Second, this article investigates the swelling behavior of new as well as thermo-oxidatively aged elastomers in synthetic fuels. For this purpose, an analysis routine is presented using sorption experiments combined with gas chromatography and mass spectrometry and is thus capable of analyzing the swelling behavior multifacetted. The transition of elastomer constituents into the surrounding fuel at different aging and sorption times is determined precisely. The change in mechanical properties is quantified using density measurements, micro Shore A hardness measurements, and the parameters stress and strain at break from uniaxial tensile tests.

Spatial variability of surface fuels in treated and untreated ponderosa pine forests of the southern Rocky Mountains

2016 ◽  
Vol 25 (11) ◽  
pp. 1156 ◽  
Author(s):  
Emma Vakili ◽  
Chad M. Hoffman ◽  
Robert E. Keane ◽  
Wade T. Tinkham ◽  
Yvette Dickinson
Keyword(s):  
Spatial Variability ◽  
Ponderosa Pine ◽  
Rocky Mountains ◽  
Wildlife Habitat ◽  
Fire Behaviour ◽  
Fuel Loading ◽  
Fuel Component ◽  
Southern Rocky Mountains ◽  
Ponderosa Pine Forests ◽  
Fuel Components

There is growing consensus that spatial variability in fuel loading at scales down to 0.5 m may govern fire behaviour and effects. However, there remains a lack of understanding of how fuels vary through space in wildland settings. This study quantifies surface fuel loading and its spatial variability in ponderosa pine sites before and after fuels treatment in the southern Rocky Mountains, USA. We found that spatial semivariance for 1- and 100-h fuels, litter and duff following thin-and-burn treatments differed from untreated sites, and was lower than thin-only sites for all fuel components except 1000-h fuels. Fuel component semivariance increased with mean fuel component loading. The scale of spatial autocorrelation for all fuel components and sites ranged from <1 to 48 m, with the shortest distances occurring for the finest fuel components (i.e. duff, litter). Component mean fuel particle diameter strongly predicted (R2 = 0.88) the distance needed to achieve sample independence. Additional work should test if these scaling relationships hold true across forested ecosystems, and could reveal fundamental processes controlling surface fuel variability. Incorporating knowledge of spatial variability into fuel sampling protocols will enhance assessment of wildlife habitat, and fire behaviour and effects modelling, over singular stand-level means.

Turbocharging a Bi-Fuel Engine to Achieve Equal Power in Natural Gas and Gasoline Modes

2006 ◽  
Author(s):  
Parham Andalibi ◽  
Mahdi Ahmadi
Keyword(s):  
Natural Gas ◽  
Mechanical Design ◽  
Chemical Properties ◽  
Volumetric Efficiency ◽  
The Other ◽  
Heat Of Vaporization ◽  
Design Concepts ◽  
Fuel Ratio ◽  
Equal Power ◽  
Gaseous Form

In bi-fuel engines, in which thermodynamic and mechanical design concepts are entirely based on gasoline mode, torque and power values are lower in natural gas mode than gasoline one. This problem is directly related to volumetric efficiency reduction in natural gas (NG) mode. Volumetric efficiency in natural gas is lower because of gaseous form of natural gas entering the engine and differences between thermo-chemical properties of natural gas and gasoline; e.g. stoichiometric air-fuel ratio and heat of vaporization. On the other hand, natural gas stoichiometric air-fuel ratio is generally greater than gasoline one and theoretically, more air should be supplied in NG mode. Although the effect of volumetric efficiency reduction is more important than another, both of them state the amount of charged air should be increased in NG mode to prevent power fall in this mode.

scholarly journals Artificial Intelligence—Engineering Magnetic Materials: Current Status and a Brief Perspective

2021 ◽  
Vol 7 (6) ◽  
pp. 84
Author(s):  
Elio A. Périgo ◽  
Rubens N. de Faria
Keyword(s):  
Artificial Intelligence ◽  
Magnetic Materials ◽  
Permanent Magnets ◽  
Chemical Properties ◽  
Soft Magnetic Materials ◽  
Current Status ◽  
Soft Magnetic ◽  
Design Concepts ◽  
Soft Magnetic Alloys ◽  
Optimal Processing

The implementation of artificial intelligence into the research and development of (currently) the most economically relevant classes of engineering hard and soft magnetic materials is addressed. Machine learning is nowadays the key approach utilized in the discovery of new compounds, physical–chemical properties prediction, microstructural/magnetic characterization, and applicability of permanent magnets and crystalline/amorphous soft magnetic alloys. Future opportunities are envisioned on at least two fronts: (a) ultra-low losses materials, as well as processes that enable their manufacturing, unlocking the next step for higher efficiency electrification, power conversion, and distribution; (b) additively manufactured magnetic materials by predicting and developing novel powdered materials properties, generative design concepts, and optimal processing conditions.

Reactive Hydrogen Content: A Tool to Predict FCC Yields

2003 ◽  
Vol 1 (1) ◽  
Author(s):  
Ernesto Mariaca-Dominguez ◽  
Silvano Rodríguez-Salomón ◽  
Rafael Maya Yescas
Keyword(s):  
Hydrogen Content ◽  
Main Product ◽  
Carbon Number ◽  
Fluid Catalytic Cracking ◽  
Reaction Conditions ◽  
Feed Composition ◽  
Cracking Behavior ◽  
Number Range ◽  
Operational Conditions

Fluid Catalytic Cracking is a process conceived to produce gasoline as the main product. Feed stocks to the process are vacuum gas oils (VGO) showing boiling point ranges typically between 343°C and 538°C. Since these boiling range cut points are usually fixed, the carbon number range of encountered hydrocarbons is approximately constant and this is also true for the relative amounts of paraffins, naphthenes and aromatics, regardless of changes from feed to feed. Under FCC reaction conditions, each of the above hydrocarbon groups exhibit different crackability. In order to explain the existing relationship between feed composition and yields and quality of end products, it is necessary to establish the effect of composition and operational conditions on cracking behavior of feedstocks, expressed in terms of a relation between some specific properties, or as in our case, by its Reactive Hydrogen Content (RHC). Therefore, yields should then be dependent on three factors, RHC value, as a measure of feed quality, catalysts and applied operational conditions. In this work, a RHC for a series of feeds of known composition is determined and correlated to conversion and yields obtained under different operational conditions, using the same catalyst. The resulting correlations are then applied to unknown feeds with the RHC being calculated from physical properties, and yields.

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