Chemical Kinetic Modeling of Combustion of Automotive Fuels


Book Description

The objectives of this report are to: (1) Develop detailed chemical kinetic reaction models for components of fuels, including olefins and cycloalkanes used in diesel, spark-ignition and HCCI engines; (2) Develop surrogate mixtures of hydrocarbon components to represent real fuels and lead to efficient reduced combustion models; and (3) Characterize the role of fuel composition on production of emissions from practical automotive engines.







Chemical Kinetics of the Gas Phase Combustion of Fuels


Book Description

Work supported by the Office of Standard Reference Data, National Bureau of Standards, Naval Sea Systems Command, Department of the Navy, and Division of Conservation, Research and Technology, Energy Research and Development Administration.




Fundamental and Semi-global Kinetic Mechanisms of Hydrocarbon Combustion. Annual Report, October 1, 1977--September 30, 1978


Book Description

Aimed at understanding practical combustion environments, present modeling efforts have been hampered by difficulties related to coupling combustion chemistry to the complex fluid mechanics present. In an attempt to circumvent such difficulties the present research program is aimed at the development of simplified chemical kinetic models (usually termed global models) to represent the combustion chemistry. Initially aimed at simple hydrocarbon fuels the program is progressing to studies of more complex aliphatics as well as important alternative fuels. The objective of this research is multifold: (a) to determine mechanistic oxidation routes of hydrocarbons derived from crudes and alternate sources, so that efficient and environmentally clean power plants based on internal and external combustion processes can be designed; (b) to develop and validate actual simplified (global) reaction rates for these hydrocarbons so that these power plants can be modelled; and (c) to develop an understanding of particulate (soot) formation to permit the rapid and successful introduction of the inexpensive, heavy, highly aromatic fuels. Studies of paraffin, olefin and alcohol hydrocarbons are reviewed. Appropriate global models are presented and compared with experimental data. The results clearly demonstrate that the turbulent flow reactor facility can be used to develop accurate global models for a variety of important fuels.




Fundamentals and Technology of Combustion


Book Description

Fundamentals and Technology of Combustion contains brief descriptions of combustion fundamental processes, followed by an extensive survey of the combustion research technology. It also includes mathematical combustion modeling of the processes covering mainly premixed and diffusion flames, where many chemical and physical processes compete in complex ways, for both laminar and turbulent flows. The combustion chemistry models that validate experimental data for different fuels are sufficiently accurate to allow confident predictions of the flame characteristics. This illustrates a unique bridge between combustion fundamentals and combustion technology, which provides a valuable technical reference for many engineers and scientists. Moreover, the book gives the reader sufficient background of basic engineering sciences such as chemistry, thermodynamics, heat transfer and fluid mechanics. The combustion research and mathematical models fit between small-scale laboratory burner flames, and large-scale industrial boilers, furnaces and combustion chambers. The materials have been collected from previous relevant research and some selected papers of the authors and co-workers, which have been presented mainly in different refereed journals, international conferences and symposia, thus providing a comprehensive collection. Furthermore, the book includes some of the many recent general correlations for the characteristics of laminar, turbulent, premixed and diffusion flames in an easily usable form. The authors believe that further progress in optimizing combustion performance and reducing polluting emissions can only be treated through understanding of combustion chemistry.




Advanced Combustion Science


Book Description

Non-uniform combustion, as encountered in diesel and gas turbine engines, furnaces, and boilers, is responsible for the conversion of fossil fuel to energy and also for the corresponding formation of pollutants. In spite of great research efforts in the past, the mechanism of non-uniform combustion has remained less explored than that of other combustion types, since it consists of many, mostly transient processes which influence each other. In view of this background, a group research project, "Exploration of Combustion Mechanism", was established to explore the mechanism of combustion, especially that of diffusive combustion, and also to find efficient ways to control the combustion process for better utilization of fuel and the reduction of pollutant emission. The group research was started, after preparatory activity of 2 years, in April 1988, for a period of 3 years, as a project with a Grant-in-Aid for Scientific Research of Priority Area subsidized by the Ministry of Education, Science and Culture of Japan. The entire group of 43 members was set up as an organizing committee of 13 members, and five research groups, consisting of 36 members. The research groups were: (1) Steady combustion, (2) Unsteady spray combustion, (3) Control of combustion, (4) Chemistry of combustion, and (5) Effects of fuels. At the beginning of the project it was agreed that we should pursue the mechanism of combustion from a scientific viewpoint, namely, the target of the project was to obtain the fundamentals, or "know why", rather than "know how" of combustion.










Chemical Kinetics of Hydrocarbon Ignition in Practical Combustion Systems


Book Description

Chemical kinetic factors of hydrocarbon oxidation are examined in a variety of ignition problems. Ignition is related to the presence of a dominant chain branching reaction mechanism that can drive a chemical system to completion in a very short period of time. Ignition in laboratory environments is studied for problems including shock tubes and rapid compression machines. Modeling of the laboratory systems are used to develop kinetic models that can be used to analyze ignition in practical systems. Two major chain branching regimes are identified, one consisting of high temperature ignition with a chain branching reaction mechanism based on the reaction between atomic hydrogen with molecular oxygen, and the second based on an intermediate temperature thermal decomposition of hydrogen peroxide. Kinetic models are then used to describe ignition in practical combustion environments, including detonations and pulse combustors for high temperature ignition, and engine knock and diesel ignition for intermediate temperature ignition. The final example of ignition in a practical environment is homogeneous charge, compression ignition (HCCI) which is shown to be a problem dominated by the kinetics intermediate temperature hydrocarbon ignition. Model results show why high hydrocarbon and CO emissions are inevitable in HCCI combustion. The conclusion of this study is that the kinetics of hydrocarbon ignition are actually quite simple, since only one or two elementary reactions are dominant. However, there are many combustion factors that can influence these two major reactions, and these are the features that vary from one practical system to another.