Download or read book Improved Modeling of Drop Vaporization and Combustion in Sprays written by and published by . This book was released on 2001 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, multicomponent and single component droplet vaporization characteristics are investigated by employing computational models. It is shown that simplified droplet vaporization models that do not solve temperature gradients or flow within the droplet and do not solve gradients in temperature or species in the immediate surrounding of the droplet are able to reproduce droplet vaporization rates and droplet lifetime with about 15% accuracy compared to detailed models for typical Diesel operating conditions. Under high temperature (> 1200 K) conditions the differences begin to increase. However, it is also shown that under such conditions as well as at even lower temperatures (> 900 K) the vaporization process is mixing limited i.e., the droplet lifetime is not controlling but rather the characteristic time for mixing of ambient air with the vapor phase the liquid, vapor and air are in phase equilibrium. It is shown that droplets are not likely to react the critical state under typical engine conditions. With application to multidimensional spray models as focus, a new model for predicting the outcome of drop collisions has been developed. Such models are important because they predict the drop sizes in the spray following atomization.
Download or read book Improved Modeling of Drop Vaporization and Combustion in Diesel Sprays written by and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This program focuses on modeling the vaporization liquid drops and the penetration of the liquid phase in Diesel sprays under cold-start conditions. This work is carried out within the framework of multidimensional modeling of the physical processes in Diesel engines. In the prior reporting period, it was shown that though vaporization of the drops under warm operating conditions may be mixing controlled whereby the drop vaporization characteristic time is much shorter than the mixing time, the vaporization rate under cold-start conditions may not be assumed to be mixing controlled. Hence, drop size effects have to be considered under cold-start conditions. In this work, a drop vaporization model under high pressure conditions is included within the context of a locally homogeneous flow assumption.
Download or read book Modeling Engine Spray and Combustion Processes written by Gunnar Stiesch and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: The utilization of mathematical models to numerically describe the performance of internal combustion engines is of great significance in the development of new and improved engines. Today, such simulation models can already be viewed as standard tools, and their importance is likely to increase further as available com puter power is expected to increase and the predictive quality of the models is constantly enhanced. This book describes and discusses the most widely used mathematical models for in-cylinder spray and combustion processes, which are the most important subprocesses affecting engine fuel consumption and pollutant emissions. The relevant thermodynamic, fluid dynamic and chemical principles are summarized, and then the application of these principles to the in-cylinder processes is ex plained. Different modeling approaches for the each subprocesses are compared and discussed with respect to the governing model assumptions and simplifica tions. Conclusions are drawn as to which model approach is appropriate for a specific type of problem in the development process of an engine. Hence, this book may serve both as a graduate level textbook for combustion engineering stu dents and as a reference for professionals employed in the field of combustion en gine modeling. The research necessary for this book was carried out during my employment as a postdoctoral scientist at the Institute of Technical Combustion (ITV) at the Uni versity of Hannover, Germany and at the Engine Research Center (ERC) at the University of Wisconsin-Madison, USA.
Download or read book Atomization and Sprays written by Arthur Lefebvre and published by CRC Press. This book was released on 1988-12-01 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atomization and Sprays examines the atomization of liquids and characteristics of sprays. It explains the physical processes of atomization as well as guidelines for designing atomizers. In addition, it demonstrates how the importance of the size and velocity of a particle contributes to improved spray characterization. Coverage includes general co
Download or read book Characteristics of Vaporizing Cryogenic Sprays for Rocket Combustion Modeling written by and published by . This book was released on 1994 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Army Research Office and Air Force Office of Scientific Research 2002 Contractors Meeting in Chemical Propulsion written by David M. Mann and published by . This book was released on 2002 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstracts are given for 6.1 basic research in chemical propulsion sponsored by the Army Research Office and the Air Force Office of Scientific Research.
Download or read book An Integrated Approach to Spray Combustion Model Development written by W. A. Sirignano and published by . This book was released on 1986 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Coarse Grained Simulation and Turbulent Mixing written by Fenando F. Grinstein and published by Cambridge University Press. This book was released on 2016-06-30 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reviews our current understanding of the subject. For graduate students and researchers in computational fluid dynamics and turbulence.
Download or read book Atomization and Sprays written by Arthur H. Lefebvre and published by CRC Press. This book was released on 2017-03-27 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second edition of this long-time bestseller provides a framework for designing and understanding sprays for a wide array of engineering applications. The text contains correlations and design tools that can be easily understood and used in relating the design of atomizers to the resulting spray behavior. Written to be accessible to readers with a modest technical background, the emphasis is on application rather than in-depth theory. Numerous examples are provided to serve as starting points for using the information in the book. Overall, this is a thoroughly updated edition that still retains the practical focus and readability of the original work by Arthur Lefebvre.
Download or read book Simulation and Optimization of Internal Combustion Engines written by Zhiyu Han and published by SAE International. This book was released on 2021-12-28 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: Simulation and Optimization of Internal Combustion Engines provides the fundamentals and up-to-date progress in multidimensional simulation and optimization of internal combustion engines. While it is impossible to include all the models in a single book, this book intends to introduce the pioneer and/or the often-used models and the physics behind them providing readers with ready-to-use knowledge. Key issues, useful modeling methodology and techniques, as well as instructive results, are discussed through examples. Readers will understand the fundamentals of these examples and be inspired to explore new ideas and means for better solutions in their studies and work. Topics include combustion basis of IC engines, mathematical descriptions of reactive flow with sprays, engine in-cylinder turbulence, fuel sprays, combustions and pollutant emissions, optimization of direct-injection gasoline engines, and optimization of diesel and alternative fuel engines.
Download or read book Combustion Theory written by Forman A. Williams and published by CRC Press. This book was released on 2018-03-05 with total page 549 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion Theory delves deeper into the science of combustion than most other texts and gives insight into combustions from a molecular and a continuum point of view. The book presents derivations of the basic equations of combustion theory and contains appendices on the background of subjects of thermodynamics, chemical kinetics, fluid dynamics, and transport processes. Diffusion flames, reactions in flows with negligible transport and the theory of pre-mixed flames are treated, as are detonation phenomena, the combustion of solid propellents, and ignition, extinction, and flamibility pehnomena.
Download or read book Experiments and Numerical Simulations of Diluted Spray Turbulent Combustion written by Bart Merci and published by Springer Science & Business Media. This book was released on 2011-06-20 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reflects the outcome of the 1st International Workshop on Turbulent Spray Combustion held in 2009 in Corsica (France). The focus is on reporting the progress of experimental and numerical techniques in two-phase flows, with emphasis on spray combustion. The motivation for studies in this area is that knowledge of the dominant phenomena and their interactions in such flow systems is essential for the development of predictive models and their use in combustor and gas turbine design. This necessitates the development of accurate experimental methods and numerical modelling techniques. The workshop aimed at providing an opportunity for experts and young researchers to present the state-of-the-art, discuss new developments or techniques and exchange ideas in the areas of experimentations, modelling and simulation of reactive multiphase flows. The first two papers reflect the contents of the invited lectures, given by experts in the field of turbulent spray combustion. The first concerns computational issues, while the second deals with experiments. These lectures initiated very interesting and interactive discussions among the researchers, further pursued in contributed poster presentations. Contributions 3 and 4 focus on some aspects of the impact of the interaction between fuel evaporation and combustion on spray combustion in the context of gas turbines, while the final article deals with the interaction between evaporation and turbulence.
Download or read book Handbook of Atomization and Sprays written by Nasser Ashgriz and published by Springer Science & Business Media. This book was released on 2011-02-18 with total page 922 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atomization and sprays are used in a wide range of industries: mechanical, chemical, aerospace, and civil engineering; material science and metallurgy; food; pharmaceutical, forestry, environmental protection; medicine; agriculture; meteorology and others. Some specific applications are spray combustion in furnaces, gas turbines and rockets, spray drying and cooling, air conditioning, powdered metallurgy, spray painting and coating, inhalation therapy, and many others. The Handbook of Atomization and Sprays will bring together the fundamental and applied material from all fields into one comprehensive source. Subject areas included in the reference are droplets, theoretical models and numerical simulations, phase Doppler particle analysis, applications, devices and more.
Download or read book Combustion of Liquid Fuel Sprays written by Alan Williams and published by Butterworth-Heinemann. This book was released on 2013-10-22 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion of Liquid Fuel Sprays outlines the fundamentals of the combustion of sprays in a unified way which may be applied to any technological application. The book begins with a discussion of the general nature of spray combustion, the sources of liquid fuels used in spray combustion, biomass sources of liquid fuels, and the nature and properties of fuel oils. Subsequent chapters focus on the properties of sprays, the atomization of liquid fuels, and the theoretical modeling of the behavior of a spray flame in a combustion chamber. The nature and control of pollutants from spray combustion, the formation of deposits in oil-fired systems, and the combustion of sprays in furnaces and engines are elucidated as well. The text is intended for students undertaking courses or research in fuel, combustion, and energy studies.
Download or read book Mechanisms of Smoke Reduction in the High Pressure Combustion of Emulsified Fuels Volume 3 Experimental Measurements and Computer Modeling of Evaporating Emulsified and Neat Fuel Sprays written by L. G. Dode and published by . This book was released on 1984 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of drop-size distributions and vaporized fuel concentrations have been combined with a spray model in the comparative study of the evaporation of sprays of emulsified and non-emulsified and non-emulsified (neat) fuels at elevated temperatures and pressures. The fuel spray was generated by a pressure jet atomizer and was polydisperse; the air stream was approximately one-dimensional turbulent flow in a constant area duct. Diagnostic techniques have been adapted or developed which allow rapid measurements of overall drop-size distributions in the presence of evaporation in high-temperature high-pressure air, and also the fuel vapor concentration distribution within sprays. It was concluded that even in conditions of turbulence and high Reynolds number for drop motion relative to the air, some emulsified fuel drops apparently undergo microexplosions. Further, it was determined that the initial atomization quality depends on te air conditions, with better atomization at higher air densities. This implies that spray drop-size measurements performed at atmospheric conditions need to be corrected for air density and temperature effects to predict atomization quality for altitude relight or high-pressure combustion. A spray model has been developed which represents the spray being studied and provides data in a form comparable to the experimental diagnostics.
Download or read book Drop Heating and Evaporation Analytical Solutions in Curvilinear Coordinate Systems written by Gianpietro Elvio Cossali and published by Springer Nature. This book was released on 2020-06-30 with total page 403 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes analytical methods for modelling drop evaporation, providing the mathematical tools needed in order to generalise transport and constitutive equations and to find analytical solutions in curvilinear coordinate systems. Transport phenomena in gas mixtures are treated in considerable detail, and the basics of differential geometry are introduced in order to describe interface-related transport phenomena. One chapter is solely devoted to the description of sixteen different orthogonal curvilinear coordinate systems, reporting explicitly on the forms of their differential operators (gradient, divergent, curl, Laplacian) and transformation matrices. The book is intended to guide the reader from mathematics, to physical descriptions, and ultimately to engineering applications, in order to demonstrate the effectiveness of applied mathematics when properly adapted to the real world. Though the book primarily addresses the needs of engineering researchers, it will also benefit graduate students.
Download or read book Recent Advances in Spray Combustion written by Kenneth K. Kuo and published by . This book was released on 1996 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:
