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Статті в журналах з теми "Detailed chemical kinetic mechanism":
1
Dai, Qian, and Hua Ye Guan. "A New Skeletal Chemical Kinetic Mechanism of Ethanol Combustion for HCCI Engine Simulation." Advanced Materials Research 614-615 (December 2012): 381–84. http://dx.doi.org/10.4028/www.scientific.net/amr.614-615.381.
Анотація:
According to the detailed chemical kinetic mechanism of ethanol proposed by the U．S．Lawrence Livermore Laboratory, this paper analyzes the main approach of ethanol oxidation. Based on the detailed chemical kinetics mechanism, a skeletal chemical reaction mechanism is presented by reaction path analysis．Thus a simplified model is constructed, which consists of 26 species and 26 reactions．And then the comparative studies were given between the simplified model and the detailed model．The simulation results show that simplified model and detailed model have good consistency.
2
PETROVA, M., and F. WILLIAMS. "A small detailed chemical-kinetic mechanism for hydrocarbon combustion." Combustion and Flame 144, no. 3 (February 2006): 526–44. http://dx.doi.org/10.1016/j.combustflame.2005.07.016.
3
Herbinet, Olivier, William J. Pitz, and Charles K. Westbrook. "Detailed chemical kinetic oxidation mechanism for a biodiesel surrogate." Combustion and Flame 154, no. 3 (August 2008): 507–28. http://dx.doi.org/10.1016/j.combustflame.2008.03.003.
4
Bunev, V. A., and A. P. Senachin. "Numerical Simulation of Hydrogen Oxidation at High Pressures Using Global Kinetics." Izvestiya of Altai State University, no. 1(123) (March 18, 2022): 83–88. http://dx.doi.org/10.14258/izvasu(2022)1-13.
Анотація:
This paper has developed and presented a new equation for the global kinetics (macrokinetics) of hydrogen oxidation at high pressures. It is based on equations for calculations of the self-ignition processes of hydrogen-air mixtures in homogeneous chemical reactors using the equations of the detailed kinetic mechanism. The choice of a detailed kinetic mechanism that describes the processes at high pressures well enough is based on a comparative analysis of a significant number of references, some of which are given in the paper. Various detailed kinetic mechanisms are compared by testing the processes of hydrogen selfignition in idealized homogeneous reactors of constant volume and constant pressure using numerical modeling of a system of ordinary differential equations describing the processes of self-ignition of hydrogen. The resulting macrokinetics equation describes the rate of hydrogen oxidation processes which, in the alternative case of a detailed kinetic mechanism, must be modeled using several dozen differential equations. The new equation of hydrogen macrokinetics is intended for the numerical simulation of physicochemical processes in developing new technologies and energy devices.
5
Schmidt, Marleen, Celina Anne Kathrin Eberl, Sascha Jacobs, Torsten Methling, Andreas Huber, and Markus Köhler. "Automatic Extension of a Semi-Detailed Synthetic Fuel Reaction Mechanism." Energies 17, no. 5 (February 20, 2024): 999. http://dx.doi.org/10.3390/en17050999.
Анотація:
To identify promising sustainable fuels, e.g., to select novel synthetic fuels with the greatest impact on minimizing global warming, new methods for rapid and economical technical fuel assessment are urgently needed. Here, numerical models that are capable of predicting technical key data quickly and without experimental setup are necessary. One method is the use of chemical kinetic models, which are able to predict the technical key parameters related to combustion behavior. For a rapid technical fuel assessment, these chemical kinetic models need to be validated for new fuel components and for different temperature and pressure ranges. This work presents a new approach to extend the existing semi-detailed chemical kinetic models. For the application of the approach, the semi-detailed reaction mechanism DLR Concise was selected and extended for the low temperature combustion modeling of n-heptane and isooctane. The open-source software reaction mechanism generator (RMG) was used for this extension. Furthermore, an optimization of the merged chemical kinetic model with the linear transformation model (linTM) was conducted in order to improve the reproducibility of ignition delay times. The improvement of the predictive performance of ignition delay times at low temperatures for both species was successfully demonstrated. Therefore, this approach can be used to quickly add new species or reaction pathways to an existing semi-detailed reaction mechanism to enable a model-based technical fuel assessment for the early identification of promising fuels.
6
Naik, Chitralkumar V., Karthik V. Puduppakkam, Abhijit Modak, Ellen Meeks, Yang L. Wang, Qiyao Feng, and Theodore T. Tsotsis. "Detailed chemical kinetic mechanism for surrogates of alternative jet fuels." Combustion and Flame 158, no. 3 (March 2011): 434–45. http://dx.doi.org/10.1016/j.combustflame.2010.09.016.
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Zettervall, Niklas, Christer Fureby, and Elna J. K. Nilsson. "Reduced Chemical Kinetic Reaction Mechanism for Dimethyl Ether-Air Combustion." Fuels 2, no. 3 (August 25, 2021): 323–44. http://dx.doi.org/10.3390/fuels2030019.
Анотація:
Development and validation of a new reduced dimethyl ether-air (DME) reaction mechanism is presented. The mechanism was developed using a modular approach that has previously been applied to several alkane and alkene fuels, and the present work pioneers the use of the modular methodology, with its underlying H/C1/O base mechanism, on an oxygenated fuel. The development methodology uses a well-characterized H/C1/O base mechanism coupled to a reduced set of fuel and intermediate product submechanisms. The mechanism for DME presented in this work includes 30 species and 69 irreversible reactions. When used in combustion simulation the mechanism accurately reproduced key combustion characteristics and the small size enables use in computationally demanding Large Eddy Simulations (LES) and Direct Numerical Simulations (DNS). It has been developed to accurately predict, among other parameters, laminar burning velocity and ignition delay times, including the negative temperature regime. The evaluation of the mechanism and comparison to experimental data and several detailed and reduced mechanisms covers a wide range of conditions with respect to temperature, pressure and fuel-to-air ratio. There is good agreement with experimental data and the detailed reference mechanisms at all investigated conditions. The mechanism uses fewer reactions than any previously presented DME-air mechanism, without losing in predictability.
8
Miyoshi, Akira. "OS3-1 KUCRS - Detailed Kinetic Mechanism Generator for Versatile Fuel Components and Mixtures(OS3 Application of chemical kinetics to combustion modeling,Organized Session Papers)." Proceedings of the International symposium on diagnostics and modeling of combustion in internal combustion engines 2012.8 (2012): 116–21. http://dx.doi.org/10.1299/jmsesdm.2012.8.116.
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Bykov, V., V. V. Gubernov, and U. Maas. "Mechanisms performance and pressure dependence of hydrogen/air burner-stabilized flames." Mathematical Modelling of Natural Phenomena 13, no. 6 (2018): 51. http://dx.doi.org/10.1051/mmnp/2018046.
Анотація:
The kinetic mechanism of hydrogen combustion is the most investigated combustion system. This is due to extreme importance of the mechanism for combustion processes, i.e. it is present as a sub-mechanism in all mechanisms for hydrocarbon combustion systems. Therefore, detailed aspects of hydrogen flames are still under active investigations, e.g. under elevated pressure, under conditions of different heat losses intensities and local equivalence ratios etc. For this purpose, the burner stabilized flame configuration is an efficient tool to study different aspects of chemical kinetics by varying the stand-off distance, pressure, temperature of the burner and mixture compositions. In the present work, a flat porous plug burner flame configuration is revisited. A hydrogen/air combustion system is considered with detailed molecular transport including thermo-diffusion and with 8 different chemical reaction mechanisms. Detailed numerical investigations are performed to single out the role of chemical kinetics on the loss of stability and on the dynamics of the flame oscillations. As a main outcome, it was found/demonstrated that the results of critical values, e.g. critical mass flow rate, weighted frequency of oscillations and blow-off velocity, with increasing the pressure scatter almost randomly. Thus, these parameters can be considered as independent and can be used to improve and to validate the mechanisms of chemical kinetics for the unsteady dynamics.
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Karra, Sankaram B., and Selim M. Senkan. "A detailed chemical kinetic mechanism for the oxidative pyrolysis of chloromethane." Industrial & Engineering Chemistry Research 27, no. 7 (July 1988): 1163–68. http://dx.doi.org/10.1021/ie00079a013.
Дисертації з теми "Detailed chemical kinetic mechanism":
1
Davidson, Jeffrey E. "Combustion Modeling of RDX, HMX and GAP with Detailed Kinetics." BYU ScholarsArchive, 1996. https://scholarsarchive.byu.edu/etd/6531.
Анотація:
A one-dimensional, steady-state numerical model of the combustion of homogeneous solid propellant has been developed. The combustion processes is modeled in three regions: solid, two-phase (liquid and gas) and gas. Conservation of energy and mass equations are solved in the two-phase and gas regions and the eigenvalue of the system (the mass burning rate) is converged by matching the heat flux at the interface of these two regions. The chemical reactions of the system are modeled using a global kinetic mechanism in the two-phase region and an elementary kinetic mechanism in the gas region. The model has been applied to RDX, HMX and GAP. There is very reasonable agreement between experimental data and model predictions for burning rate, temperature sensitivity, surface temperature, adiabatic flame temperature, species concentration profiles and melt-layer thickness. Many of the similarities and differences in the combustion of RDX and HMX are explained from sensitivity analysis results. The combustion characteristics of RDX and HMX are similar because of their similar chemistry. Differences in combustion characteristics arise due to differences in melting temperature, vapor pressure and initial decomposition steps. A reduced mechanism consisting of 18 species and 39 reactions was developed from the Melius-Yetter RDX mechanism (45 species, 232 reactions). This reduced mechanism reproduces most of the predictions of the full mechanism but is 7.5 times faster. Because of lack of concrete thermophysical property data for GAP, the modeling results are preliminary but indicate what type of experimental data is necessary before GAP can be modeled with more certainty.
2
Shaheen, Zeiwar Hussein [Verfasser], Bernd [Akademischer Betreuer] Rogg, and Viktor [Akademischer Betreuer] Scherer. "Development of detailed and reduced bio-diesel kinetic chemical mechanisms / Zeiwar Hussein Shaheen. Gutachter: Bernd Rogg ; Viktor Scherer." Bochum : Ruhr-Universität Bochum, 2016. http://d-nb.info/1082425818/34.
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Dmitriev, Artëm. "Kinetic study of ester biofuels in flames." Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0238.
Анотація:
Le progrès partout dans le monde nécessite une variété de sources d'énergie propre. Les biocarburants liquides de type ester semblent être très efficaces dans ce contexte, car ils sont faciles à utiliser dans les véhicules modernes, ils peuvent être produits à partir de diverses ressources renouvelables et ils offrent des caractéristiques de combustion respectueuses de l'environnement. À cet égard, les esters éthyliques d'acides gras (EEAG) sont considérés comme une classe prometteuse de biocarburants. L'objectif principal de cette thèse était de développer un mécanisme cinétique chimique actualisé de la combustion des EEAG légers jusqu'au pentanoate d'éthyle et de le valider par rapport aux nouvelles données expérimentales sur la structure de flammes laminaires prémélangées à basse pression et pression atmosphérique. Les flammes alimentées par trois EEAG, l'acétate d'éthyle, le butanoate d'éthyle et le pentanoate d'éthyle, ont été étudiées au moyen de la spectrométrie de masse avec faisceau moléculaire et de la chromatographie en phase gazeuse. Plus de 40 espèces stables et intermédiaires comprenant des radicaux ont été détectées et quantifiées dans les flammes. Une analyse complète du mécanisme développé a été réalisée. La thèse se compose de 3 chapitres. Le premier chapitre présente une revue bibliographique. Les études expérimentales et théoriques les plus importantes sur la combustion des EEAG sont discutées. Le deuxième chapitre présente un aperçu des méthodes expérimentales et de simulation utilisées dans la thèse. Des détails sur le développement du mécanisme sont également fournis dans cette partie. Le dernier chapitre présente des résultats expérimentaux et de modélisation sur les esters étudiés en comparaison avec les mécanismes cinétiques de la littératureGlobal progress all over the world requires a variety of clean energy sources. Liquid ester-based biofuels seem to be very effective in this context since they are easy to use in modern vehicles, they can be produced from a variety of renewable resources, and they provide environmentally friendly combustion characteristics. In this regard, fatty acid ethyl esters (FAEEs) are considered as a promising class of biofuels. The main goal of this thesis was to develop an updated chemical kinetic mechanism of combustion of light FAEEs up to ethyl pentanoate and validate it against the new experimental data on chemical speciation in low and atmospheric pressure premixed laminar flames. The flames fueled by three FAEEs, ethyl acetate, ethyl butanoate and ethyl pentanoate, were investigated by means of molecular-beam mass-spectrometry and gas-chromatography. More than 40 stable and intermediate species including radicals were detected and quantified in the flames. A comprehensive analysis of the developed mechanism was performed. The thesis consists of 3 chapters. In the first chapter a review of literature is presented. The most important experimental and theoretic studies on FAEEs are discussed. The second chapter presents an overview of experimental and simulation methods used in the work. Details on the mechanism development are also provided in this part. The last chapter present experimental and modeling results on the esters studied in comparison with the literature kinetic mechanisms
4
Maurice, Lourdes Quintana. "Detailed chemical kinetic models for aviation fuels." Thesis, Imperial College London, 1996. http://hdl.handle.net/10044/1/8153.
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Potter, Mark Lee. "Detailed chemical kinetic modelling of propulsion fuels." Thesis, Imperial College London, 2004. http://hdl.handle.net/10044/1/7995.
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Rizos, Konstantinos-Athanassios. "Detailed chemical kinetic modelling of homogeneous systems." Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.407143.
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Park, Sung-Woo. "Detailed chemical kinetic model for oxygenated fuels." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/9599.
Анотація:
A detailed chemical kinetic model is developed and tested for the combustion of C2 and C3 oxygenated fuels such as ethanol, DME (dimethyl ether), acetone and n-propanol. It is validated by comparing predictions with experimental data on the structure of low pressure burner stabilised premixed flames and laminar burning velocities over a wide range of equivalence ratios. Data from shock tube and stirred reactor studies has also been considered. The elementary reactions of ethanol and DME oxidation have been studied extensively and were used as a starting point for extension to C3 oxygenated fuels. The chemistry of acetylene which is one of major intermediate species in higher hydrocarbon flames was also updated to improve the reliability of the present mechanism and acetylene laminar burning velocities and low-pressure premixed lean and rich flames were also computed. The detailed mechanism features more than 1500 reaction steps and 269 species. The structure of laminar premixed flames are predicted by using measured temperature profiles and conditions cover fuel-lean and fuel-rich mixtures at low pressure. The profiles of reactants, products and major intermediate species are compared to experimental data from mass spectrometry and the overall agreement between the kinetic model and experimental data is satisfactory. An analytic study of fuel consumption pathways is carried out to understand the detailed consumption pathways. The present mechanism is also tested against laminar flame speeds by calculating freely propagating premixed flames to extend the understanding of the combustion characteristics of oxygenated fuels. A sensitivity analysis is also performed.
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Pacheco, Augusto Finger. "Analysis and reduction of detailed chemical kinetics mechanisms for combustion of ethanol and air." reponame:Repositório Institucional da UFSC, 2016. https://repositorio.ufsc.br/xmlui/handle/123456789/172793.
Анотація:
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2016.Made available in DSpace on 2017-01-31T03:11:16Z (GMT). No. of bitstreams: 1 343953.pdf: 3011153 bytes, checksum: 751769c238df128576bd611ed9f3178b (MD5) Previous issue date: 2016
Neste trabalho, três mecanismos detalhados de cinética química para o etanol, disponíveis na literatura, foram submetidos a diferentes métodos de redução, utilizando condições encontradas na operação normal de motores de combustão interna como parâmetros de redução. O primeiro mecanismo selecionado foi desenvolvido por Leplat e colaboradores (2011), no ICARE, em Orleans, França, contendo 252 reações químicas reversíveis, compreendendo 38 espécies, obtido principalmente para reproduzir medidas de concentrações de espécies em reatores perfeitamente misturados. O segundo por Mittal e colaboradores (2014), no C3-NUI, na Irlanda, envolvendo 710 reações químicas reversíveis, englobando 111 espécies, desenvolvido para prever os atrasos de ignição medidos em máquinas de compressão rápida. O terceiro mecanismo selecionado foi produzido por Cancino e colaboradores (2010), do IVG, Alemanha, e da UFSC, Brasil, contendo 1349 reações químicas reversíveis, compreendendo 35 espécies, feito principalmente para prever atrasos de ignição à alta pressão em tubos de choque. Os métodos de redução selecionados foram: Sensitivity Analysis (SA), Rate of Production (ROP), Direct Relation Graph (DRG), Direct Relation Graph with Error Propagation (DRGEP) e Path Flux Analysis (PFA). Sendo o mecanismo do Leplat o mais compacto, este foi utilizado para avaliar a redução final e a razão de convergência de cada método estudado. Ambos, atrasos de ignição (Ignition Delay Times, IDT) e velocidade de chama laminar, compreendidos em um grande intervalo de condições de temperatura, pressão e razão de equivalência foram selecionados como parâmetros de redução. Da análise inicial, os métodos DRG e DRGEP apresentaram as maiores eficiências, tanto em termos de tamanho final do mecanismo reduzido como nos termos de taxa de remoção de espécies. Assim, ambos os métodos foram sistematicamente aplicados nos outros mecanismos e as diferenças entre as espécies removidas foram avaliadas. O mecanismo final obtido via DRGEP para o mecanismo do Leplat apresentou, respectivamente, 84% e 72% das espécies e reações do mecanismo detalhado. Para o mecanismo do Cancino, o DRGEP apresentou uma maior redução, com 58% e 61% respectivamente das espécies e reações sem remover o mecanismo de oxidação do nitrogênio e ainda representando o IDT à altas pressões com uma diferença menor de 5% do mecanismo detalhado. Finalmente, para o mecanismo do Mittal, o método DRG apresentou a maior redução, atingindo 37% das espécies e 34% das reações do mecanismo detalhado. A análise de sensibilidade dos mecanismos reduzidos revelaram o mesmo grupo de reações como as mais sensíveis para a chama laminar e IDT dos apresentados pelos mecanismos detalhados, indicando que a redução não modifica a razão de importância das reações dentro de um caminho de reação para um dado mecanismo. Entretanto, ao comparar os mecanismos reduzidos entre si, muitas diferenças se tornam visíveis, como a modelagem dos fenômenos inicias ou finais da combustão. Estas observações podem auxiliar e dirigir o desenvolvimento de mecanismos cinéticos mais abrangentes para a modelagem da combustão de etanol.
Abstract : In this work, three detailed kinetic mechanisms available in the literature were subjected to different methods of reduction, using the conditions found on internal combustion engines normal operation as reduction targets. The mechanisms selected were those of Leplat and co-workers (2011), from ICARE, Orleans, France, containing 252 reversible chemical reactions among 38 chemical species, developed mainly to reproduce measurements of species concentration in perfectly-stirred reactors; of Mittal and co-workers (2014), from C3-NUI, Ireland, involving 710 reversible chemical reactions among 111 chemical species, developed mainly to predict ignition delay time measured in rapid compression machine; and that of Cancino and co-workers (2010), from IVG, Germany, and UFSC, Brazil, involving 1349 reversible chemical reactions among 135 chemical species, mainly developed to predict high-pressure ignition delay time measured in shock tubes. The reduction methods selected were the Sensitivity Analysis (SA), Rate of Production (ROP), Directed Relation Graph (DRG) and Directed Relation Graph with Error Propagation (DRGEP) and Path Flux Analysis (PFA). Since Leplat's mechanism is the most compact, it was selected for the assessment of the final reduction and convergence ratio involved in each reduction method studied. Both ignition delay time and laminar flame speed, evaluated over a large range of temperature, pressure and equivalence ratios, were selected as reduction targets. The maximum difference allowed between the predictions of the full detailed and the reduced mechanisms was 5 % over the entire target range. From the initial analysis, the DRG and DRGEP methods appeared as the most effective, both in terms of the size of the final reduced mechanism, as well as in terms of the rate of removal of species. The DRG and DRGEP methods were then systematically applied to the other mechanisms and the differences observed in the reduced species were noted and analyzed. The final reduced mechanism obtained via DRGEP from Leplat´s mechanism presented, respectively, 84 % and 72 % of the species and reactions of the detailed mechanism. For the Cancino mechanism, the DRGEP produced a larger reduction with 58 % and 61 % of species and reactions respectively of the detailed mechanism, without removing the nitrogen oxidation mechanism and still representing the high-pressure IDT with a 5% difference from the detailed mechanism. Finally, for the Mittal mechanism, the DRG method presented the largest reduction, reaching 37% of species and 34% of reactions of the detailed mechanism. The sensitivity analysis of the reduced mechanisms revealed the same group of most sensitive reactions in respect to the laminar flame and ignition delay time as the detailed mechanism, indicating that the reduction does not change the relative importance of the reactions within a reaction path for a given mechanism. However, when the reduced mechanisms are compared among them, several basic differences arise, mainly in the level of detail, expressed as the number of intermediates and reactions, placed in modeling early or late kinetics phenomena. These observations may lead to the development of more comprehensive mechanisms for the modeling of ethanol combustion.
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Porter, Richard Thomas James. "Kinetic mechanism reduction for chemical process hazard application." Thesis, University of Leeds, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.441227.
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Cho, Yong Kweon. "Kinetic and Chemical Mechanism of Pyrophosphate-Dependent Phosphofructokinase." Thesis, University of North Texas, 1988. https://digital.library.unt.edu/ark:/67531/metadc332128/.
Анотація:
Data obtained from isotope exchange at equilibrium, exchange of inorganic phosphate against forward reaction flux, and positional isotope exchange of 18O from the (βγ-bridge position of pyrophosphate to a (β-nonbridge position all indicate that the pyrophosphate-dependent phosphofructokinase from Propionibacterium freudenreichii has a rapid equilibrium random kinetic mechanism. All exchange reactions are strongly inhibited at high concentrations of the fructose 6-phosphate/Pi and MgPPi/Pi substrate-product pairs and weakly inhibited at high concentrations of the MgPPi/fructose 1,6-bisphosphate pair suggesting three dead-end complexes, E:F6P:Pi, E:MgPPi:Pi, and E:FBP:MgPPi. Neither back-exchange by [32p] nor positional isotope exchange of 18O-bridge-labeled pyrophosphate was observed under any conditions, suggesting that either the chemical interconversion step or a step prior to it limits the overall rate of the reaction. Reduction of the pyridoxal 5'-phosphate-inactivated enzyme with NaB[3H]4 indicates that about 7 lysines are modified in free enzyme and fructose 1,6-bisphosphate protects 2 of these from modification. The pH dependence of the enzyme-reactant dissociation constants suggests that the phosphates of fructose 6-phosphate, fructose 1,6-bisphosphate, inorganic phosphate, and Mg-pyrophosphate must be completely ionized and that lysines are present in the vicinity of the 1- and 6-phosphates of the sugar phosphate and bisphosphates probably directly coordinated to these phosphates. The pH dependence of kinetic parameters suggests that the enzyme catalyzes its reaction via general acid-base catalysis with the use of a proton shuttle. The base is required unprotonated in both reaction directions. In the direction of fructose 6-phosphate phosphorylation the base accepts a proton from the hydroxyl at C-l of F6P and then donates it to protonate the leaving phosphate. The maximum velocity of the reaction is pH independent in both reaction directions while V/K profiles exhibit pKs for binding groups (including enzyme and reactant functional groups) as well as pKs for enzyme catalytic groups. These data suggest that reactants bind only when correctly protonated and only to the correctly protonated form of the enzyme.
Книги з теми "Detailed chemical kinetic mechanism":
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Whitten, G. Z. Development of a chemical kinetic mechanism for the U.S. EPA regional oxidant model. Research Triangle Park, NC: U.S. Environmental Protection Agency, Atmospheric Sciences Research Laboratory, 1985.
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Battin-Leclerc, Frédérique, John M. Simmie, and Edward Blurock. Cleaner Combustion: Developing Detailed Chemical Kinetic Models. Springer, 2016.
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Battin-Leclerc, Frédérique, John M. Simmie, and Edward Blurock. Cleaner Combustion: Developing Detailed Chemical Kinetic Models. Springer, 2013.
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Simmie, John M., Edward Blurock, and édérique Battin-Leclerc. Cleaner Combustion: Developing Detailed Chemical Kinetic Models. Springer London, Limited, 2013.
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McManus-Muñoz, Silvia. Kinetic mechanism of metallo- -lactamase L1 from Stenotrophomonas maltophilia. 1999.
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McManus-Muñoz, Silvia. Kinetic mechanism of metallo- -lactamase L1 from Stenotrophomonas maltophilia. 1999.
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L, Schramm Vern, and Purich Daniel L, eds. Enzyme kinetics and mechanism. 1999.
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Gochfeld, Michael, and Robert Laumbach. Chemical Hazards. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190662677.003.0011.
Анотація:
Building on the principles of toxicology, this chapter describes chemicals by structure, source, use, mechanism of action, environmental properties, and target organ. Major advances in toxic effects include more detailed understanding of the mechanisms by which toxic chemicals damage receptors at the subcellular, cellular, and organ level. The chapter describes properties of various types of inorganic and organic chemicals and their adverse health effects. It discusses asphyxiants, such as carbon monoxide and hydrogen sulfide; heavy metals, such as lead, mercury, and cadmium; organic solvents, such as benzene and trichlorethylene; pesticides, including chlorinated hydrocarbons and organophosphates; and a variety of other toxic chemicals to which people are exposed in the home, community, or workplace environment. Several cases are presented to illustrate various concepts concerning chemical hazards in occupational and environmental health.
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Bernstein, Elliot R., ed. Chemical Reactions in Clusters. Oxford University Press, 1996. http://dx.doi.org/10.1093/oso/9780195090048.001.0001.
Анотація:
This book covers important new developments of the last five years in the area of cluster chemistry, presenting an excellent view of the successes and shortcomings of both current state-of-the-art theory and experiment. Each chapter, contributed by a leading expert, places heavy emphasis on theory without which the detailed analysis of the spectroscopic and kinetic results would be compromised. The cluster reactions reviewed in this work include electron and proton transfer reactions, hot atom reactions, vibrational predissociation, radical reactions, and ionic reactions. Some of the theories applied throughout the text are product state distribution determinations, state-to-state dynamical information, and access to the transition stage of the reaction. The discussions serve as a benchmark of how far the field has come since the mid 1980's and will be a good update for students and researchers interested in this area of physical chemistry.
Частини книг з теми "Detailed chemical kinetic mechanism":
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Patel, Jay, Prathamesh Phadke, Rohit Sehrawat, Arvind Kumar, Arindrajit Chowdhury, and Neeraj Kumbhakarna. "Detailed Chemical Kinetics Mechanism for Condensed Phase Decomposition of Ammonium Perchlorate." In Fluid Mechanics and Fluid Power, Volume 4, 133–43. Singapore: Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-99-7177-0_12.
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Lopato, Alexander I. "Some Aspects on Pulsating Detonation Wave Numerical Simulation Using Detailed Chemical Kinetics Mechanism." In Applied Mathematics and Computational Mechanics for Smart Applications, 103–14. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-33-4826-4_8.
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Lopato, Alexander I. "Numerical Simulation of Shock-To-Detonation Transition Using One-Stage and Detailed Chemical Kinetics Mechanism." In Smart Modelling for Engineering Systems, 79–88. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-33-4619-2_7.
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Liberman, Michael A. "Unsteady Combustion Processes Controlled by Detailed Chemical Kinetics." In Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 317–41. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-11967-0_20.
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Frenklach, Michael, and Hai Wang. "Detailed Mechanism and Modeling of Soot Particle Formation." In Springer Series in Chemical Physics, 165–92. Berlin, Heidelberg: Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/978-3-642-85167-4_10.
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Varfolomeev, Sergey, Viktor Bykov, and Svetlana Tsybenova. "Kinetic modelling of processes in the cholinergic synapse. Mechanisms of functioning and control methods." In ORGANOPHOSPHORUS NEUROTOXINS, 127–39. ru: Publishing Center RIOR, 2020. http://dx.doi.org/10.29039/22_127-139.
Анотація:
The kinetic model describing the dynamics of synaptic “discharge” taking into account the kinetics of the injection of the neurotransmitter into the synaptic cleft, the pH-dependence of catalytic activity of the enzyme and diffusion withdrawal of protons is proposed and studied. In the framework of the kinetic model, the functioning of the cholinergic synapse is considered. The results of mathematical modeling of changes in the level of acetylcholine, induced pH impulse, the influence of the frequency of impulse transfer and inhibition of acetylcholinesterase are presented. Physico-chemical explanation for a number of important physiological phenomena, such as neuromuscular paralysis, the molecular mechanism of neurological memory, actions of nerve poisons and toxins and Alzheimer’s disease is given.
7
Varfolomeev, Sergey, Viktor Bykov, and Svetlana Tsybenova. "Kinetic modelling of processes in the cholinergic synapse. Mechanisms of functioning and control methods." In Organophosphorous Neurotoxins, 121–33. ru: Publishing Center RIOR, 2020. http://dx.doi.org/10.29039/chapter_5e4132b600e1c6.27895580.
Анотація:
The kinetic model describing the dynamics of synaptic “discharge” taking into account the kinetics of the injection of the neurotransmitter into the synaptic cleft, the pH-dependence of catalytic activity of the enzyme and diffusion withdrawal of protons is proposed and studied. In the framework of the kinetic model, the functioning of the cholinergic synapse is considered. The results of mathematical modeling of changes in the level of acetylcholine, induced pH impulse, the influence of the frequency of impulse transfer and inhibition of acetylcholinesterase are presented. Physico-chemical explanation for a number of important physiological phenomena, such as neuromuscular paralysis, the molecular mechanism of neurological memory, actions of nerve poisons and toxins and Alzheimer’s disease is given.
8
Law, D. W., C. Gunasekara, and S. Setunge. "Use of Brown Coal Ash as a Replacement of Cement in Concrete Masonry Bricks." In Lecture Notes in Civil Engineering, 23–25. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-3330-3_4.
Анотація:
AbstractPortland cement production is not regarded as environmentally friendly, because of its associated high carbon emissions, which are responsible for 5% of global emissions. An alternative is to substitute fly ash for Portland cement. Australia has an abundance of brown coal fly ash, as it is the main source of primary energy in the State of Victoria. Currently, the majority of this material is stored in landfills and currently there is no commercial use for it in the cement industry because brown coal fly ash cannot be used as a direct replacement material for Portland cement due to the high sulfur and calcium content and low aluminosilicate content. However, the potential exists to use brown coal fly ash as a geopolymeric material, but there remains a significant amount of research needed to be conducted. One possible application is the production of geopolymer concrete bricks. A research project was undertaken to investigate the use of brown coal fly ash from Latrobe Valley power stations in the manufacture of geopolymer masonry bricks. The research developed a detailed understanding of the fundamental chemistry behind the activation of the brown coal fly ash and the reaction mechanisms involved to enable the development of brown coal fly ash geopolymer concrete bricks. The research identified suitable manufacturing techniques to investigate relationships between compressive strength and processing parameters and to understand the reaction kinetics and microstructural developments. The first phase of the research determined the physical, chemical, and mineralogical properties of the Loy Yang and Yallourn fly ash samples to produce a 100% fly ash-based geopolymer mortar. Optimization of the Loy Yang and Yallourn geopolymer mortars was conducted to identify the chemical properties that were influential in the production of satisfactory geopolymer strength. The Loy Yang mortars were able to produce characteristic compressive strengths acceptable in load-bearing bricks (15 MPa), whereas the Yallourn mortars produced characteristic compressive strengths only acceptable as non-load-bearing bricks (5 MPa). The second phase of the research transposed the optimal geopolymer mortar mix designs into optimal geopolymer concrete mix designs while merging the mix design with the optimal Adbri Masonry (commercial partner) concrete brick mix design. The reference mix designs allowed for optimization of both the Loy Yang and Yallourn geopolymer concrete mix designs, with the Loy Yang mix requiring increased water content because the original mix design was deemed to be too dry. The key factors that influenced the compressive strength of the geopolymer mortars and concrete were identified. The amorphous content was considered a vital aspect during the initial reaction process of the fly ash geopolymers. The amount of unburnt carbon content contained in the fly ash can hinder the reactive process, and ultimately, the compressive strength because unburnt carbon can absorb the activating solution, thus reducing the particle to liquid interaction ratio in conjunction with lowering workability. Also, fly ash with a higher surface area showed lower flowability than fly ash with a smaller surface area. It was identified that higher quantity of fly ash particles <45 microns increased reactivity whereas primarily angular-shaped fly ash suffered from reduced workability. The optimal range of workability lay between the 110–150 mm slump, which corresponded with higher strength displayed for each respective precursor fly ash. Higher quantities of aluminum incorporated into the silicate matrix during the reaction process led to improved compressive strengths, illustrated by the formation of reactive aluminosilicate bonds in the range of 800–1000 cm–1 after geopolymerization, which is evidence of a high degree of reaction. In addition, a more negative fly ash zeta potential of the ash was identified as improving the initial deprotonation and overall reactivity of the geopolymer, whereas a less negative zeta potential of the mortar led to increased agglomeration and improved gel development. Following geopolymerization, increases in the quantity of quartz and decreases in moganite correlated with improved compressive strength of the geopolymers. Overall, Loy Yang geopolymers performed better, primarily due to the higher aluminosilicate content than its Yallourn counterpart. The final step was to transition the optimal geopolymer concrete mix designs to producing commercially acceptable bricks. The results showed that the structural integrity of the specimens was reduced in larger batches, indicating that reactivity was reduced, as was compressive strength. It was identified that there was a relationship between heat transfer, curing regimen and structural integrity in a large-volume geopolymer brick application. Geopolymer bricks were successfully produced from the Loy Yang fly ash, which achieved 15 MPa, suitable for application as a structural brick. Further research is required to understand the relationship between the properties of the fly ash, mixing parameters, curing procedures and the overall process of brown coal geopolymer concrete brick application. In particular, optimizing the production process with regard to reducing the curing temperature to ≤80 °C from the current 120 °C and the use of a one-part solid activator to replace the current liquid activator combination of sodium hydroxide and sodium silicate.
9
Williams, Neil. "Light-Element Stable Isotope Studies of the Clastic-Dominated Lead–Zinc Mineral Systems of Northern Australia and the North American Cordillera: Implications for Ore Genesis and Exploration." In Isotopes in Economic Geology, Metallogenesis and Exploration, 329–72. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-27897-6_11.
Анотація:
AbstractClastic-dominated lead–zinc (CD Pb–Zn) deposits are an important source of the world’s Pb and Zn supply. Their genesis is contentious due to uncertainties regarding the time of ore formation relative to the deposition of the fine-grained carbonaceous strata that host CD Pb–Zn mineralization. Sulfur-isotopic studies are playing an important role in determining if ore minerals precipitated when hydrothermal fluids exhaled into the water column from which the host strata were being deposited, or when hydrothermal fluids entered the host strata during diagenesis or even later after lithification. Older conventional S-isotopic studies, based on analyses of bulk mineral-separate samples obtained by either physical or chemical separation methods, provided data that has been widely used to support a syngenetic-exhalative origin for CD Pb–Zn mineralization. However, with the advent in the late 1980’s of in situ S-isotopic studies using micro-analytical methods, it soon became apparent that detailed S-isotopic variations of genetic importance are blurred in conventional analytical data sets because of averaging during sample preparation. Clastic-dominated Pb–Zn mineralization in the North Australian Proterozoic metallogenic province and the North American Paleozoic Cordilleran province has been the subject of many stable isotope studies based on both bulk and in situ analytical methods. Together with detailed mineral texture observations, the studies have revealed a similar sulfide mineral paragenesis in both provinces. The earliest sulfide phase in the paragenesis is fine-grained pyrite that sometimes has a framboidal texture. This pyrite typically has a wide range of δ34S values that are more than 15‰ lower than the value of coeval seawater sulfate. These features are typical of, and very strong evidence for, pyrite formation by bacterial sulfate reduction (BSR) either syngenetically in an anoxic water column or during early diagenesis in anoxic muds. The formation of this early pyrite is followed by one or more later generations of pyrite that often occur as overgrowths around the early pyrite generation. The later pyrite generations have δ34S values that are much higher than the early pyrite, often approaching the value of coeval seawater sulfate. Later pyrite formation has been variously attributed to BSR in a more restricted diagenetic environment, to sulfate driven-anaerobic oxidation of methane (SD-AOM) and to abiotic thermal sulfate reduction (TSR), with all three mechanisms again involving coeval seawater sulfate. The main sulfide ore minerals, galena and sphalerite, either overlap with or postdate later pyrite generations and are most often attributed to TSR of seawater sulfate. However, in comparison with pyrite, there is a dearth of in situ δ34S data for galena and sphalerite that needs to be rectified to better understand ore forming processes. Importantly, the available data do not support a simple sedimentary-exhalative model for the formation of all but part of one of the Northern American and Australian deposits. The exception is the giant Red Dog deposit group in Alaska where various lines of evidence, including stable isotopic data, indicate that ore formation was protracted, ranging from early syn-sedimentary to early diagenetic sulfide formation through to late sulfide deposition in veins and breccias. The Red Dog deposits are the only example with early sphalerite with extremely low negative δ34S values typical of a BSR-driven precipitation mechanism. By contrast, later stages of pyrite, sphalerite and galena have higher positive δ34S values indicative of a TSR-driven precipitation mechanism. In CD Pb–Zn deposits in carbonate-bearing strata, carbon and oxygen isotope studies of the carbonates provide evidence that the dominant carbonate species in the ore-forming hydrothermal fluids was H2CO3, and that the fluids were initially warm (≥ 150 °C) and neutral to acid. The δ18O values of the hydrothermal fluids are ≥ 6‰, suggesting these fluids were basinal fluids that evolved through exchange with the basinal sedimentary rocks. Known CD Pb–Zn deposits all occur at or near current land surfaces and their discovery involved traditional prospecting, geophysical and geochemical exploration techniques. Light stable isotopes are unlikely to play a significant role in the future search for new CD Pb–Zn deposits deep beneath current land surfaces, but are likely to prove useful in identifying ore-forming hydrothermal fluid pathways in buried CD Pb–Zn systems and be a vector to new mineralization.
10
Arshad, Muzammil. "Numerical Simulations and Validation of Engine Performance Parameters Using Chemical Kinetics." In Numerical Simulation [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.106536.
Анотація:
Use of detailed chemistry augments the combustion model of a three-dimensional unsteady compressible turbulent Navier–Stokes solver with liquid spray injection when coupled with fluid mechanics solution with detailed kinetic reactions. Reduced chemical reaction mechanisms help in the reducing the simulations time to study of the engine performance parameters, such as, in-cylinder pressure in spark ignition engines. Sensitivity analysis must be performed to reduce the reaction mechanism for the compression and power strokes utilizing computational singular perturbation (CSP) method. To study a suitable well-established surrogate fuel, an interface between fluid dynamics and chemical kinetics codes must be used. A mesh independent study must be followed to validate results obtained from numerical simulations against the experimental data. To obtain comprehensive results, a detailed study should be performed for all ranges of equivalence ratios as well as stoichiometric condition. This gives rise to the development of a reduced mechanism that has the capability to validate engine performance parameters from stoichiometric to rich mixtures in a spark ignition engine. The above-mentioned detailed methodology was developed and implemented in the present study for premixed and direct injection spark ignition engines which resulted in a single reduced reaction mechanism that validated the engine performance parameters for both engine configurations.
Тези доповідей конференцій з теми "Detailed chemical kinetic mechanism":
1
Mawid, M. A., T. W. Park, B. Sekar, and C. Arana. "Detailed Chemical Kinetic Modeling of JP-8/Jet-A Ignition and Combustion." In ASME Turbo Expo 2005: Power for Land, Sea, and Air. ASMEDC, 2005. http://dx.doi.org/10.1115/gt2005-68829.
Анотація:
Significant progress towards development and validation of a detailed chemical kinetic mechanism for the US Air Force JP-8 fuel is presented in this article. Three detailed chemical kinetic mechanisms for three JP-8 surrogate fuels, as given in Table I, were developed and reported in this study. The main objective is to investigate the performance of the developed three mechanisms for three different surrogate fuel blends and determine the suitability of each mechanism to chemically model the US Air Force petroleum-derived JP-fuel. The detailed JP-8 chemical kinetic reaction mechanism, we have been developing [1–3] for a 12-component surrogate fuel blend, has been used as a basis for the development of two additional detailed reaction mechanisms for the other two surrogate fuel mixtures. Submechanisms for the monosubstituted aromatics such as toluene, m-xylene, butylbenzene, and for the bicyclic aromatics such as 1-methylnaphthalene were all assembled and integrated with the detailed JP-8 reaction mechanism [1–3]. Pressure-dependent rate parameters up to 10 atmospheres for 41 reactions were also included. The three mechanisms were evaluated by predicting the ignition and combustion characteristics of a JP-8 fuel-air mixture in Plug Flow Reactor (PFR) and a Perfectly-Stirred Reactor (PSR) over a temperature range of 933–1020 K and pressure of 1 atm. The results indicated that overall the mechanism for the 6-component JP-8 surrogate 3 (Table I) can predict similar ignition-delay periods as those predicted by the 12-component JP-8 surrogate fuel 1 for atmospheric pressure condition. However, the PSR calculations pointed out to the existence of differences in lighter hydrocarbon species concentration profiles such as CH4, C2H4, C3H6, and C4H8 and important emission species such as CO and CO2 as predicted by the mechanisms that exhibited comparable ignition delay times. The study suggests that, for the conditions considered here, that the developed mechanisms still require further evaluation under various combustion environments, including transport phenomena, to determine the suitability of the chemical kinetic mechanism for either surrogate fuel 1 or 3 to chemically simulate the actual US Air Force JP-8 fuel.
2
Park, Tae, Mohammed Mawid, Balu Sekar, Carlos Arana, and S. Aithal. "Development of a Detailed Chemical Kinetic Mechanism for Combustion of JP-7 Fuel." In 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2003. http://dx.doi.org/10.2514/6.2003-4939.
3
Cantore, Giuseppe, Luca Montorsi, Fabian Mauss, Per Amne´us, Olof Erlandsson, Bengt Johansson, and Thomas Morel. "Analysis of a 6 Cylinder Turbocharged HCCI Engine Using a Detailed Kinetic Mechanism." In ASME 2002 Internal Combustion Engine Division Spring Technical Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/ices2002-457.
Анотація:
When analyzing HCCI combustion engine behavior, the integration of experimental tests and numerical simulations is crucial. Investigations of possible engine control strategies as a function of the different operating conditions have to take the behavior of the whole HCCI engine into account, including the effects both of the combustion process and of complex devices. Therefore the numerical simulation code must be able both to model accurately the gas-dynamic of the system and to evaluate the combustion chemical kinetics. This paper focuses on the coupling between the commercial one-dimensional fluid-dynamic GT-Power Code and our in-house detailed chemical kinetic Ignition Code. An interface has been developed in order to exchange information between the two codes: the Ignition Code considers as boundary conditions the GT-Power Code values provided for the gas composition at IVC and the pressure and temperature at every time step and passes back to GT-Power the burnt fuel fraction and stores in an external file the in cylinder gas composition. Thus the whole engine cycle can be accurately simulated, estimating the interactions between the gas-dynamics phenomena along the intake and exhaust pipes and through the valves, and the chemical processes occurring during the closed valves period. This tool makes it possible to analyze the engine behavior under duty cycle operating conditions, and therefore it represents a useful support to the experimental measurements, reducing the number of tests required to assess the proper engine control strategies.
4
Mawid, M. A., and B. Sekar. "Development of a Detailed JP-8/Jet-A Chemical Kinetic Mechanism for High Pressure Conditions in Gas Turbine Combustors." In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-90478.
Анотація:
Pressure conditions under which chemical reactions proceed in gas turbine combustors impact the behavior of the combustion process by either increasing or decreasing the reaction rates depending on whether these reactions are unimolecular/recombination or chemically activated bimolecular reactions. Some reactions are pressure independent such as H-abstraction reactions, while others are conditionally pressure independent if they are not at their either low or high limits. The recombination and decomposition of kinetic reactions rate constants change relative to their limiting values as the pressure and/or temperature conditions vary and as a result the reactants concentrations and reactions pathways are also influenced. In this study, pressure-dependent kinetic rate parameters for 39 elementary reactions have been added to our detailed JP-8/Jet-A kinetic reaction mechanism, we have developed [1–3, 23, 58], to model ignition of JP-8 and Jet-A fuels behind a reflected shock wave. The main objective is to develop a detailed chemical kinetic reaction mechanism for low and high pressure combustion conditions, using a 6-component surrogate fuel blend considered to represent the actual (petroleum-derived) JP-8 and Jet-A fuels. The pressure-dependent kinetic rate parameters for 39 reactions have been incorporated into our low pressure detailed JP-8 chemical kinetic reaction mechanism to generate the fall-off curves for the Arrehnius rate parameters required for low and high pressure ignition analysis. The new JP-8 detailed mechanism has been evaluated, using a stoichiometric JP-8/02/N2 and Jet-A/air mixtures, over a temperature range of 968–1639 K and a pressure range of 10 to 34 atmosphere by predicting auto-ignition delay times and comparing them to the shock tube ignition data of Minsk, Sarikovskii, and Hanson [56]. The results indicated that the developed JP-8/Jet-A reaction mechanism is capable of reproducing the qualitative ignition trends of the measured ignition data behind a reflected shock wave. However, the detailed kinetic reaction mechanism overestimated the measured ignition delay times. The results also suggested that additional more reactions are high pressure-dependent under the conditions considered in this study and as such a need still exists for experimentally measured kinetic rate coefficients for high pressure ignition and combustion conditions. This study, therefore, warrants further experiments and detailed kinetic analysis.
5
Bolin, Christopher D., and Abraham Engeda. "Modeling Static Instabilities of Biogas Flames in a Stirred-Reactor Using Detailed Chemical Kinetics Simulations." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-95095.
Анотація:
Kinetic modeling of lean static stability limits of the combustion of biogas type fuels in a model of an ideal primary zone of a gas turbine combustor is presented here. In this study, CH4 is diluted with CO2 to simulate a range of gases representative of the products of anaerobic digestion of organic materials from different sources (e.g., landfill and animal waste digester). Fuels of this type are of interest for use in small gas turbines used in distributed generation applications. Predictions made by two detailed mechanisms (GRI-Mech 3.0 and San Diego) and one reduced mechanism (GRI-Mech 1.2, reduced) are employed to investigate the underlying kinetics near lean extinction. Approximate correlations to lean extinction are extracted from these results and compared to those of other fuels.
6
Som, S., Z. Wang, W. Liu, and D. E. Longman. "Comparison of Different Chemical Kinetic Models for Biodiesel Combustion." In ASME 2013 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/icef2013-19094.
Анотація:
The current study compares the predictions by four different published mechanisms in literature which have been used for 3 dimensional compression ignition engine simulations. These four mechanisms use two different sets of surrogates: (a) methyl decanoate, methyl 9-decenoate, and n-heptane, (b) methyl butanoate and n-heptane. The mechanisms include: (1) 115 species and 460 reactions [1] using surrogate mixture (a); (2) 77 species and 209 reactions [2] using surrogate mixture (a); (3) 145 species and 869 reactions [3] using surrogate mixture (b); (4) 41 species and 150 reactions [4] using surrogate mixture (b). The different reduction techniques implemented to obtain the reduced mechanisms from the detailed mechanisms are briefly described. The surrogate mixture compositions are then modified to match the cetane number of the real biodiesel fuels. The experimental data for comparison include jet-stirred reactor data for species concentrations for biodiesel derived from rapeseed oil and 3 dimensional constant volume combustion data (for ignition, combustion, and emission characteristics), engine data (for pressure, heat release rate, and emission characteristics) for soy-derived biodiesel. 0-D and 3-D constant volume simulations with all the mechanisms can capture the general experimental trends quite well. Large surrogate models and mechanisms tend to provide better predictions at the expense of increased computational costs. The 115 species and 460 reaction mechanism was observed to perform the best among the mechanisms in predicting the jet-stirred reactor and 3-D constant volume data. It was observed that all the mechanisms are able to qualitatively capture the engine performance and emission characteristics.
7
Braun-Unkhoff, Marina, Nadezhda Slavinskaya, and Manfred Aigner. "A Detailed and Reduced Reaction Mechanism of Biomass-Based Syngas Fuels." In ASME Turbo Expo 2009: Power for Land, Sea, and Air. ASMEDC, 2009. http://dx.doi.org/10.1115/gt2009-60214.
Анотація:
In the present work, the elaboration of a reduced kinetic reaction mechanism is described which predicts reliably fundamental characteristic combustion properties of two biogenic gas mixtures consisting mainly of hydrogen, methane, and carbon monoxide, with small amounts of higher hydrocarbons (ethane and propane), in different proportions. From the in-house detailed chemical kinetic reaction mechanism with about 55 species and 460 reactions, a reduced kinetic reaction mechanism was constructed consisting of 27 species and 130 reactions. Their predictive capability concerning laminar flame speed (measured at T0 = 323 K, 373 K and 453 K, at p = 1 bar, 3 bar, and 6 bar for equivalence ratios φ between 0.6 and 2.2) and auto ignition data (measured in a shock tube between 1035 and 1365 K at pressures around 16 bar for φ = 0.5 and 1.0) are discussed in detail. Good agreement was found between experimental and calculated values within the investigated parameter range.
8
Martinez-Morett, David, Luigi Tozzi, and Anthony J. Marchese. "A Reduced Chemical Kinetic Mechanism for CFD Simulations of High BMEP, Lean-Burn Natural Gas Engines." In ASME 2012 Internal Combustion Engine Division Spring Technical Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ices2012-81109.
Анотація:
Recent developments in numerical techniques and computational processing power now permit time-dependent, multi-dimensional computational fluid dynamic (CFD) calculations with reduced chemical kinetic mechanisms (approx. 20 species and 100 reactions). Such computations have the potential to be highly effective tools for designing lean-burn, high BMEP natural gas engines that achieve high fuel efficiency and low emissions. Specifically, these CFD simulations can provide the analytical tools required to design highly optimized natural gas engine components such as pistons, intake ports, precombustion chambers, fuel systems and ignition systems. To accurately model the transient, multi-dimensional chemically reacting flows present in these systems, chemical kinetic mechanisms are needed that accurately reproduce measured combustion data at high pressures and lean conditions, but are of sufficient size to enable reasonable computational times. Presently these CFD models cannot be used as accurate design tools for application in high BMEP lean-burn gas engines because existing detailed and reduced mechanisms fail to accurately reproduce experimental flame speed and ignition delay data for natural gas at high pressure (40 atm and higher) and lean (0.6 equivalence ratio (ϕ) and lower) conditions. Existing methane oxidation mechanisms have typically been validated with experimental conditions at atmospheric and intermediate pressures (1 to 20 atm) and relatively rich stoichiometry. These kinetic mechanisms are not adequate for CFD simulation of natural gas combustion in which elevated pressures and very lean conditions are typical. This paper provides an analysis, based on experimental data, of the laminar flame speed computed from numerous, detailed chemical kinetic mechanisms for methane combustion at pressures and equivalence ratios necessary for accurate high BMEP, lean-burn natural gas engine modeling. A reduced mechanism that was shown previously to best match data at moderately lean and high pressure conditions was updated for the conditions of interest by performing sensitivity analysis using CHEMKIN. The reaction rate constants from the most sensitive reactions were appropriately adjusted in order to obtain a better agreement at high pressure lean conditions. An evaluation of this adjusted mechanism, “MD19”, was performed using Converge CFD software. The results were compared to engine data and a remarkable improvement on combustion performance prediction was obtained with the MD19 mechanism.
9
Gokulakrishnan, P., M. S. Klassen, and R. J. Roby. "Development of Detailed Kinetic Mechanism to Study Low Temperature Ignition Phenomenon of Kerosene." In ASME Turbo Expo 2005: Power for Land, Sea, and Air. ASMEDC, 2005. http://dx.doi.org/10.1115/gt2005-68268.
Анотація:
The objective of this work is to develop a detailed kinetic mechanism for low temperature kerosene oxidation, which is essential to predict premature auto-ignition of liquid fuels in gas turbines and cool flame behavior in hydrocarbon reformers for fuel cells. Kerosene, a fractional distillate of petroleum known by its generic term, is comprised of a wide range of aviation fuel grades such as Jet A, Jet-4, JP-8 etc, with a chemical composition varying from higher order n-alkanes to complex aromatics. Thus, developing a detailed kinetic mechanism to represent actual kerosene is not only cumbersome but also computationally intensive to implement. Therefore, very often a surrogate mixture with known chemical composition is devised to study kerosene oxidation. In this work, a hierarchical structure of the kerosene mechanism with approximately 1400 reactions of 550 species is developed using a surrogate mixture of n-decane, n-propylcyclohexane and n-propylbenzene to represent major components of kerosene, namely n-alkanes, cyclo-alkanes and aromatics, respectively. Since a major portion of the kerosene consists of very reactive n-alkanes rather than the less reactive ring structures, the low temperature oxidation kinetics is predominantly dictated by n-alkanes. Thus, the modeling effort is mainly focused on developing a low temperature mechanism for n-decane. The low-temperature oxidation of the individual fuel of the surrogate mixture, especially n-decane, was fairly well-characterized experimentally in shock-tubes and flow-reactors, and hence, the mechanism is validated against the available experimental measurements. With the objective of achieving a more comprehensive mechanism, the model validation is extended to include target data for wide range of conditions including high pressure and high temperature experimental data available in the literature. The model predictions of the kerosene mechanism were compared to the available experimental data on ignition delay time as well as the reactivity species profiles of different aviation grade fuels obtained in flow reactors. The predictions of the kerosene mechanism agree with the experimental data fairly well especially at low to intermediate temperature regimes. A sensitivity analysis was performed to identify the rate-limiting steps at low, intermediate and high temperatures. It was observed that reactions involving ketohydroperoxides and hydrogen-peroxides are the most important reactions at low and intermediate temperatures, respectively.
10
Gokulakrishnan, P., S. Kwon, A. J. Hamer, M. S. Klassen, and R. J. Roby. "Reduced Kinetic Mechanism for Reactive Flow Simulation of Syngas/Methane Combustion at Gas Turbine Conditions." In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-90573.
Анотація:
The reduced kinetic mechanism for syngas/methane developed in the present work consists of a global reaction step for fuel decomposition in which the fuel molecule breaks down into CH2O and H2. A detailed CH2O/H2/O2 elementary reaction sub-set is included as the formation of intermediate combustion radicals such as OH, H, O, HO2, and H2O2 is essential for accurate predictions of non-equilibrium phenomena such as ignition and extinction. Since the chemical kinetics of H2 and CH2O are the fundamental building blocks of any hydrocarbon oxidation, the inclusion of detailed kinetic mechanisms for CH2O and H2 oxidation enables the reduced mechanism to predict over a wide range of operating conditions provided the reaction rate parameters of fuel-decomposition reaction is optimized over those conditions. Therefore, the rate coefficients for the fuel-decomposition step are estimated and optimized for the ignition delay time measurements of CH4, H2, CH4/H2, CH4/CO and CO/H2 mixtures available in the literature over a wide range of pressures, temperatures and equivalence ratios that are relevant to gas turbine operating conditions. The optimized reduced mechanism, consisting of 15 species and around 40 reactions, is able to predict the ignition delay time and laminar flame speed measurements of CH4, H2, CH4/H2, CH4/CO and CO/H2 mixtures fairly well over a wide range conditions. The model predictions are also compared with that of GRI3.0 mechanism. The reduced kinetic mechanism predicts the ignition delay time of CH4 and CH4/H2 mixtures far better than GRI mechanism at higher pressures. To demonstrate the predictive capability of the model in reactive flow systems, the reduced mechanism was implemented in Star-CD/KINetics commercial code using a RANS turbulence model to simulate CH4/air premixed combustion in a backward facing step. The CFD model predictions of the stable species in the exhaust gas agree well with the GRI mechanism predictions in a chemical reactor network modeling by approximating the backward facing step with a series of perfectly-stirred reactor and plug-flow reactor.
Звіти організацій з теми "Detailed chemical kinetic mechanism":
1
Marinov, N. Detailed chemical kinetic model for ethanol oxidation. Office of Scientific and Technical Information (OSTI), April 1997. http://dx.doi.org/10.2172/611758.
2
Banin, Amos, Joseph Stucki, and Joel Kostka. Redox Processes in Soils Irrigated with Reclaimed Sewage Effluents: Field Cycles and Basic Mechanism. United States Department of Agriculture, July 2004. http://dx.doi.org/10.32747/2004.7695870.bard.
Анотація:
The overall objectives of the project were: (a) To measure and study in situ the effect of irrigation with reclaimed sewage effluents on redox processes and related chemical dynamics in soil profiles of agricultural fields. (b) To study under controlled conditions the kinetics and equilibrium states of selected processes that affect redox conditions in field soils or that are effected by them. Specifically, these include the effects on heavy metals sorption and desorption, and the effect on pesticide degradation. On the basis of the initial results from the field study, increased effort was devoted to clarifying and quantifying the effects of plants and water regime on the soil's redox potential while the study of heavy metals sorption was limited. The use of reclaimed sewage effluents as agricultural irrigation water is increasing at a significant rate. The relatively high levels of suspended and, especially, dissolved organic matter and nitrogen in effluents may affect the redox regime in field soils irrigated with them. In turn, the changes in redox regime may affect, among other parameters, the organic matter and nitrogen dynamics of the root zone and trace organic decomposition processes. Detailed data of the redox potential regime in field plots is lacking, and the detailed mechanisms of its control are obscure and not quantified. The study established the feasibility of long-term, non-disturbing monitoring of redox potential regime in field soils. This may enable to manage soil redox under conditions of continued inputs of wastewater. The importance of controlling the degree of wastewater treatment, particularly of adding ultrafiltration steps and/or tertiary treatment, may be assessed based on these and similar results. Low redox potential was measured in a field site (Site A, KibutzGivat Brenner), that has been irrigated with effluents for 30 years and was used for 15 years for continuous commercial sod production. A permanently reduced horizon (Time weighted averaged pe= 0.33±3.0) was found in this site at the 15 cm depth throughout the measurement period of 10 months. A drastic cultivation intervention, involving prolonged drying and deep plowing operations may be required to reclaim such soils. Site B, characterized by a loamy texture, irrigated with tap water for about 20 years was oxidized (Time weighted average pe=8.1±1.0) throughout the measurement period. Iron in the solid phases of the Givat Brenner soils is chemically-reduced by irrigation. Reduced Fe in these soils causes a change in reactivity toward the pesticide oxamyl, which has been determined to be both cytotoxic and genotoxic to mammalian cells. Reaction of oxamyl with reduced-Fe clay minerals dramatically decreases its cytotoxicity and genotoxicity to mammalian cells. Some other pesticides are affected in the same manner, whereas others are affected in the opposite direction (become more cyto- and genotoxic). Iron-reducing bacteria (FeRB) are abundant in the Givat Brenner soils. FeRB are capable of coupling the oxidation of small molecular weight carbon compounds (fermentation products) to the respiration of iron under anoxic conditions, such as those that occur under flooded soil conditions. FeRB from these soils utilize a variety of Fe forms, including Fe-containing clay minerals, as the sole electron acceptor. Daily cycles of the soil redox potential were discovered and documented in controlled-conditions lysimeter experiments. In the oxic range (pe=12-8) soil redox potential cycling is attributed to the effect of the daily temperature cycle on the equilibrium constant of the oxygenation reaction of H⁺ to form H₂O, and is observed under both effluent and freshwater irrigation. The presence of plants affects considerably the redox potential regime of soils. Redox potential cycling coupled to the irrigation cycles is observed when the soil becomes anoxic and the redox potential is controlled by the Fe(III)/Fe(II) redox couple. This is particularly seen when plants are grown. Re-oxidation of the soil after soil drying at the end of an irrigation cycle is affected to some degree by the water quality. Surprisingly, the results suggest that under certain conditions recovery is less pronounced in the freshwater irrigated soils.
3
Flowers, Daniel L. Combustion in Homogeneous Charge Compression Ignition Engines: Experiments and Detailed Chemical Kinetic Simulations. Office of Scientific and Technical Information (OSTI), June 2002. http://dx.doi.org/10.2172/15006123.
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Sessa, Guido, and Gregory Martin. A functional genomics approach to dissect resistance of tomato to bacterial spot disease. United States Department of Agriculture, January 2004. http://dx.doi.org/10.32747/2004.7695876.bard.
Анотація:
The research problem. Bacterial spot disease in tomato is of great economic importance worldwide and it is particularly severe in warm and moist areas affecting yield and quality of tomato fruits. Causal agent of spot disease is the Gram-negative bacterium Xanthomonas campestris pv. vesicatoria (Xcv), which can be a contaminant on tomato seeds, or survive in plant debris and in association with certain weeds. Despite the economic significance of spot disease, plant protection against Xcvby cultural practices and chemical control have so far proven unsuccessful. In addition, breeding for resistance to bacterial spot in tomato has been undermined by the genetic complexity of the available sources of resistance and by the multiple races of the pathogen. Genetic resistance to specific Xcvraces have been identified in tomato lines that develop a hypersensitive response and additional defense responses upon bacterial challenge. Central goals of this research were: 1. To identify plant genes involved in signaling and defense responses that result in the onset of resistance. 2. To characterize molecular properties and mode of action of bacterial proteins, which function as avirulence or virulence factors during the interaction between Xcvand resistant or susceptible tomato plants, respectively. Our main achievements during this research program are in three major areas: 1. Identification of differentially expressed genes during the resistance response of tomato to Xcvrace T3. A combination of suppression subtractive hybridization and microarray analysis identified a large set of tomato genes that are induced or repressed during the response of resistant plants to avirulent XcvT3 bacteria. These genes were grouped in clusters based on coordinate expression kinetics, and classified into over 20 functional classes. Among them we identified genes that are directly modulated by expression of the type III effector protein AvrXv3 and genes that are induced also during the tomato resistance response to Pseudomonas syringae pv. tomato. 2. Characterization of molecular and biochemical properties of the tomato LeMPK3MAP kinase. A detailed molecular and biochemical analysis was performed for LeMPK3 MAP kinase, which was among the genes induced by XcvT3 in resistant tomato plants. LeMPK3 was induced at the mRNA level by different pathogens, elicitors, and wounding, but not by defense-related plant hormones. Moreover, an induction of LeMPK3 kinase activity was observed in resistant tomato plants upon Xcvinfection. LeMPK3 was biochemically defined as a dual-specificity MAP kinase, and extensively characterized in vitro in terms of kinase activity, sites and mechanism of autophosphorylation, divalent cation preference, Kₘand Vₘₐₓ values for ATP. 3. Characteriztion of molecular properties of the Xcveffector protein AvrRxv. The avirulence gene avrRxvis involved in the genetic interaction that determines tomato resistance to Xcvrace T1. We found that AvrRxv functions inside the plant cell, localizes to the cytoplasm, and is sufficient to confer avirulence to virulent Xcvstrains. In addition, we showed that the AvrRxv cysteine protease catalytic core is essential for host recognition. Finally, insights into cellular processes activated by AvrRxv expression in resistant plants were obtained by microarray analysis of 8,600 tomato genes. Scientific and agricultural significance: The findings of these activities depict a comprehensive and detailed picture of cellular processes taking place during the onset of tomato resistance to Xcv. In this research, a large pool of genes, which may be involved in the control and execution of plant defense responses, was identified and the stage is set for the dissection of signaling pathways specifically triggered by Xcv.
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Hedrick, Jacob, and Timothy Jacobs. PR-457-14201-R02 Variable NG Composition Effects in LB 2S Compressor Engines Phase I Engine Response. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), August 2015. http://dx.doi.org/10.55274/r0010997.
Анотація:
This is the final report summarizing work completed during the first phase of the PRCI study on large bore two stroke lean burn integral compressor engine response to variable natural gas compositions for the purposes of engine control development. Accomplished tasks include the completion of a detailed literature review covering the research topic, a parametric study of laminar flame speeds and ignition delays for binary methane and ethane mixtures up to 30%, and a GT-Power engine model of the Colorado State GMV-4 research engine with associated validation data from CSU�s variable ethane effects study. The chemistry of the combustion reaction is crucial to accurate modeling; laminar flame speeds and ignition delays as function of composition were determined from the solutions to published chemical kinetics mechanisms GRI-Mech3.0 and Saudi Aramco Mech1.3, respectively. The Wiebe coefficients correlated to variations in ethane composition and spark timing were regressed from the crank angle resolved heat release rates. The Wiebe coefficients are the most significant achievement of this phase of the project, since they quantify the heat release as a function of composition. At this time, the Wiebe parameters only reflect the relative changes in the model since certain aspect of the models geometry are pending resolution. Future phases of the project could use the developed GT-Power model and Wiebe coefficients for development of control schemes that maintain emissions, speed and torque limits, and maximize thermal efficiency during a variable fuel composition event.
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Linker, Taylor, and Timothy Jacobs. PR-457-18204-R01 Variable Fuel Effects on Legacy Compressor Engines Phase IV - Predictive NOx Modeling. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), May 2019. http://dx.doi.org/10.55274/r0011584.
Анотація:
The ultimate goal of this work is to improve the current control methods for large bore, lean burn natural gas engines in order to combat performance and emissions issues during variable fuel composition events. This will be achieved in the long term by simulating the effects of variable fuel composition on a large bore, natural gas engine and developing engine control strategies which work to mitigate adverse effects. The work of Phase IV adds onto previous work by enabling the prediction of NOxemissions in the validated, full-scale engine simulation of a Cooper-Bessemer GMWH-10C developed in Phase III. A sweep of fuel composition was also performed to assess the effect that variable fuel composition has on in-cylinder properties and NOxemissions. Engine-out NOxwas predicted via a chemical kinetic mechanism which was implemented into the existing engine simulation. The mechanism dictates the composition of combustion products in each cylinder, including NO and NO2(NOx). NOxlevels were measured at the simulation exhaust to compare with the experimental NOxdata acquired as part of the data collection carried out in Phase III of this project. The prediction was tuned in order to achieve the closest prediction to real measured NOxvalues. A preliminary sweep of fuel composition was completed by varying the mole fractions of ethane and propane within the natural gas compositions used in the simulation. Changes in in-cylinder pressure, location of peak pressure, in-cylinder temperature, and engine-out NOxwere evaluated based on their trend-wise behavior and compared qualitatively to expected results.