Download or read book Transient Spray Combustion Computations written by William A. Sirignano and published by . This book was released on 1986 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many practical combustion devices involves direct injection of liquid fuel into the combustion chamber, e.g., gas turbine engines, diesel engines, rockets and ramjet engines, and furnaces. Typically, the fuel is of sufficiently low volatility that vaporization is an important or controlling factor in the rate of combustion. It is desirable, therefore, to analyze the trajectories, heating, and vaporization of the large number of droplets in a fuel spray and to account for the exchange of mass, momentum, and energy between the liquid and gas phases in order to predict combustor performance, stability, and pollutant emission. A review is made of one-dimensional, unsteady and axisymmetric, unsteady spray combustion calculations. Proper formulation of the governing two-phase equations are discussed. Problems of ignition and flame propagation are examined. Since droplet lifetime is of the same order to magnitude as time for heat transport through the droplet, transient heating of the droplets is considered together with effects of internal droplet circulation due to shear forces on the droplet surface. Keywords: Sprays, Combustion, Ignition, Fuels, Droplets, Vaporization, Drag.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thirteenth Workshop for Computational Fluid Dynamic Applications in Rocket Propulsion and Launch Vehicle Technology written by and published by . This book was released on 1996 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Numerical Simulations of Stationary and Transient Spray Combustion for Aircraft Gas Turbine Applications written by Athanase Alain Fossi and published by . This book was released on 2017 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of current and future aero gas turbine engines is mainly focused on the safety, the performance, the energy consumption, and increasingly on the reduction of pollutants and noise level. To this end, the engine's design phases are subjected to improving processes continuously through experimental and numerical investigations. The present thesis is concerned with the simulation of transient and steady combustion regimes in an aircraft gas turbine operating under various combustion modes. Particular attention is paid to the accuracy of the results, the computational cost, and the ease of handling the numerical tool from an industrial standpoint. Thus, a commercial Computational Fluid Dynamics (CFD) code widely used in industry is selected as the numerical tool. A CFD methodology consisting of its advanced turbulence and combustion models, coupled with a subgrid spark-based ignition model, is formulated with the final goal of predicting the whole ignition sequence under cold start and altitude relight conditions, and the main flame trends in the steady combustion regime. At first, attention is focused on the steady combustion regime. Various CFD methodologies are formulated using three turbulence models, namely, the Unsteady Reynolds-Averaged Navier-Stokes (URANS), the Scale-Adaptive Simulation (SAS), and the Large Eddy Simulation (LES) models. To appraise the relevance of incorporating a realistic chemistry model and chemical non-equilibrium effects, two different assumptions are considered, namely, the infinitely-fast chemistry through the partial equilibrium model, and the finite-rate chemistry through the diffusion flamelet model. For each of the two assumptions, both one-component and two-component fuels are considered as surrogates for kerosene (Jet A-1). The resulting CFD models are applied to a swirl-stabilized combustion chamber to assess their ability to retrieve the spray flow and combustion properties in the steady combustion regime. Subsequently, the ratios between the accuracy of the results and the computational cost of the three CFD methodologies are explicitly compared. The second intermediate study is devoted to the ignition sequence preceding the steady combustion regime. A bluff-body stabilized burner based on gaseous fuel, and employing a spark-based igniter, is considered to calibrate the CFD model formulated. This burner of relatively simple geometry can provide greater understanding of complex reactive flow features, especially with regard to ignitability and stability. The most robust of the CFD methodologies formulated in the previous configuration is reconsidered. As this burner involves a partially-premixed combustion mode, a combustion model based on the mixture fraction-progress variable formulation is adopted with the assumptions of infinitely-fast chemistry and finite-rate chemistry through the Bray-Moss-Libby (BML) and Flamelet Generated Manifold (FGM) models, respectively. The ignition model is first customized by implementing the properties of the flame considered. Thereafter, the customized ignition model is coupled to the LES solver and combustion models based on the two above-listed assumptions. To assess the predictive capabilities of the resulting CFD methodologies, the latter are used to predict ignition events resulting from the spark deposition at various locations of the burner, and the results are quantitatively and qualitatively validated by comparing the latter to their experimental counterparts. Finally, the CFD methodology validated in the gaseous configuration is extended to spray combustion by first coupling the latter to the spray module, and by implementing the flame properties of kerosene in the ignition model. The resulting CFD model is first applied to the swirl-stabilized combustor investigated previously, with the aim of predicting the whole ignition sequence and improving the previous predictions of the combustion properties in the resulting steady regime. Subsequently, the CFD methodology is applied to a scaled can combustor with the aim of predicting ignition events under cold start and altitude relight operating conditions. The ability of the CFD methodology to predict ignition events under the two operating conditions is assessed by contrasting the numerical predictions to the corresponding experimental ignition envelopes. A qualitative validation of the ignition sequence is also done by comparing the numerical ignition sequence to the high-speed camera images of the corresponding ignition event.
Download or read book Technical Reports Awareness Circular TRAC written by and published by . This book was released on 1987-08 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fluid Dynamics and Transport of Droplets and Sprays written by W. A. Sirignano and published by Cambridge University Press. This book was released on 1999-07-28 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: An authoritative review of the science and technology of droplets and sprays.
Download or read book A Transient Spray Mixing Model for Diesel Combustion written by W. S. Chiu and published by . This book was released on 1976 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1990 with total page 980 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advanced Combustion Science written by Tsuneo Someya and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Research in Progress written by and published by . This book was released on 1983 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1996 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Research in Progress written by United States. Army Research Office and published by . This book was released on 1984 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. for 1977- consist of two parts: Chemistry, biological sciences, engineering sciences, metallurgy and materials science (issued in the spring); and Physics, electronics, mathematics, geosciences (issued in the fall).
Download or read book Spray Combustion Processes in Steady and Non steady Flow Systems written by Robert Dewey Sutton and published by . This book was released on 1971 with total page 856 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dust Explosion Dynamics written by Russell A. Ogle and published by Butterworth-Heinemann. This book was released on 2016-09-10 with total page 687 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dust Explosion Dynamics focuses on the combustion science that governs the behavior of the three primary hazards of combustible dust: dust explosions, flash fires, and smoldering. It explores the use of fundamental principles to evaluate the magnitude of combustible dust hazards in a variety of settings. Models are developed to describe dust combustion phenomena using the principles of thermodynamics, transport phenomena, and chemical kinetics. Simple, tractable models are described first and compared with experimental data, followed by more sophisticated models to help with future challenges. Dr. Ogle introduces the reader to just enough combustion science so that they may read, interpret, and use the scientific literature published on combustible dusts. This introductory text is intended to be a practical guide to the application of combustible dust models, suitable for both students and experienced engineers. It will help you to describe the dynamics of explosions and fires involving dust and evaluate their consequences which in turn will help you prevent damage to property, injury and loss of life from combustible dust accidents. - Demonstrates how the fundamental principles of combustion science can be applied to understand the ignition, propagation, and extinction of dust explosions - Explores fundamental concepts through model-building and comparisons with empirical data - Provides detailed examples to give a thorough insight into the hazards of combustible dust as well as an introduction to relevant scientific literature
Download or read book Tenth Workshop for Computational Fluid Dynamic Applications in Rocket Propulsion written by and published by . This book was released on 1992 with total page 742 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computational Fluid Dynamics written by T. J. Chung and published by Cambridge University Press. This book was released on 2010-09-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The second edition of Computational Fluid Dynamics represents a significant improvement from the first edition. However, the original idea of including all computational fluid dynamics methods (FDM, FEM, FVM); all mesh generation schemes; and physical applications to turbulence, combustion, acoustics, radiative heat transfer, multiphase flow, electromagnetic flow, and general relativity is still maintained. The second edition includes a new section on preconditioning for EBE-GMRES and a complete revision of the section on flowfield-dependent variation methods, which demonstrates more detailed computational processes and includes additional example problems. For those instructors desiring a textbook that contains homework assignments, a variety of problems for FDM, FEM and FVM are included in an appendix. To facilitate students and practitioners intending to develop a large-scale computer code, an example of FORTRAN code capable of solving compressible, incompressible, viscous, inviscid, 1D, 2D and 3D for all speed regimes using the flowfield-dependent variation method is made available.
