Download or read book Scramjet Combustion Modeling Using Eddy Dissipation Model written by Jimmy-John O. E. Hoste and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Large eddy Simulations of Scramjet Engines written by Heeseok Koo and published by . This book was released on 2011 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main objective of this dissertation is to develop large-eddy simulation (LES) based computational tools for supersonic inlet and combustor design. In the recent past, LES methodology has emerged as a viable tool for modeling turbulent combustion. LES computes the large scale mixing process accurately, thereby providing a better starting point for small-scale models that describe the combustion process. In fact, combustion models developed in the context of Reynolds-averaged Navier Stokes (RANS) equations exhibit better predictive capability when used in the LES framework. The development of a predictive computational tool based on LES will provide a significant boost to the design of scramjet engines. Although LES has been used widely in the simulation of subsonic turbulent flows, its application to high-speed flows has been hampered by a variety of modeling and numerical issues. In this work, we develop a comprehensive LES methodology for supersonic flows, focusing on the simulation of scramjet engine components. This work is divided into three sections. First, a robust compressible flow solver for a generalized high-speed flow configuration is developed. By using carefully designed numerical schemes, dissipative errors associated with discretization methods for high-speed flows are minimized. Multiblock and immersed boundary method are used to handle scramjet-specific geometries. Second, a new combustion model for compressible reactive flows is developed. Subsonic combustion models are not directly applicable in high-speed flows due to the coupling between the energy and velocity fields. Here, a probability density function (PDF) approach is developed for high-speed combustion. This method requires solution to a high dimensional PDF transport equation, which is achieved through a novel direct quadrature method of moments (DQMOM). The combustion model is validated using experiments on supersonic reacting flows. Finally, the LES methodology is used to study the inlet-isolator component of a dual-mode scramjet. The isolator is a critical component that maintains the compression shock structures required for stable combustor operation in ramjet mode. We simulate unsteady dynamics inside an experimental isolator, including the propagation of an unstart event that leads to loss of compression. Using a suite of simulations, the sensitivity of the results to LES models and numerical implementation is studied.
Download or read book Scramjet Propulsion written by E. T. Curran and published by AIAA. This book was released on 2001 with total page 1354 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scramjet Combustion written by Gautam Choubey and published by Butterworth-Heinemann. This book was released on 2022-07-08 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scramjet Combustion explores the development of a high-speed scramjet engine operating in the supersonic/hypersonic range for various air and space transport applications. The book explains the basic structure, components, working cycle, and the relevant governing equations in a clear manner that speaks to both advanced and more novice audiences. Particular attention is paid to efficient air–fuel combustion, looking at both the underlying fundamentals of combustion as well strategies for obtaining optimum combustion efficiency. Methods for reaching the chemically correct air–fuel ratio, subsequent flame, and combustion stabilization as air enters at supersonic speed are also outlined. Further, it includes the continuous on-going efforts, innovations, and advances with respect to the design modification of scramjet combustors, as well as different strategies of fuel injections for obtaining augmented performance while highlighting the current and future challenges. - Outlines the fundamentals of scramjet engines including their basic structure and components, working cycle, governing equations, and combustion fundamentals affecting the combustion and mixing processes - Presents new design modifications of scramjet combustors and different fuel injection strategies including combined fuel injection approaches - Discusses core topics such as chemical kinetics in supersonic flow, fuel–air mixing methods, strategies for combating combustion difficulties, and subsequent flame and combustion stabilization that can be applied to scramjets - Describes the pedagogy for computational approaches in simulating supersonic flows
Download or read book Modeling and Simulation of Turbulent Combustion written by Santanu De and published by Springer. This book was released on 2017-12-12 with total page 663 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a comprehensive review of state-of-the-art models for turbulent combustion, with special emphasis on the theory, development and applications of combustion models in practical combustion systems. It simplifies the complex multi-scale and nonlinear interaction between chemistry and turbulence to allow a broader audience to understand the modeling and numerical simulations of turbulent combustion, which remains at the forefront of research due to its industrial relevance. Further, the book provides a holistic view by covering a diverse range of basic and advanced topics—from the fundamentals of turbulence–chemistry interactions, role of high-performance computing in combustion simulations, and optimization and reduction techniques for chemical kinetics, to state-of-the-art modeling strategies for turbulent premixed and nonpremixed combustion and their applications in engineering contexts.
Download or read book Turbulent Combustion Modeling written by Tarek Echekki and published by Springer Science & Business Media. This book was released on 2010-12-25 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent combustion sits at the interface of two important nonlinear, multiscale phenomena: chemistry and turbulence. Its study is extremely timely in view of the need to develop new combustion technologies in order to address challenges associated with climate change, energy source uncertainty, and air pollution. Despite the fact that modeling of turbulent combustion is a subject that has been researched for a number of years, its complexity implies that key issues are still eluding, and a theoretical description that is accurate enough to make turbulent combustion models rigorous and quantitative for industrial use is still lacking. In this book, prominent experts review most of the available approaches in modeling turbulent combustion, with particular focus on the exploding increase in computational resources that has allowed the simulation of increasingly detailed phenomena. The relevant algorithms are presented, the theoretical methods are explained, and various application examples are given. The book is intended for a relatively broad audience, including seasoned researchers and graduate students in engineering, applied mathematics and computational science, engine designers and computational fluid dynamics (CFD) practitioners, scientists at funding agencies, and anyone wishing to understand the state-of-the-art and the future directions of this scientifically challenging and practically important field.
Download or read book Turbulent Combustion written by Norbert Peters and published by Cambridge University Press. This book was released on 2000-08-15 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: The combustion of fossil fuels remains a key technology for the foreseeable future. It is therefore important that we understand the mechanisms of combustion and, in particular, the role of turbulence within this process. Combustion always takes place within a turbulent flow field for two reasons: turbulence increases the mixing process and enhances combustion, but at the same time combustion releases heat which generates flow instability through buoyancy, thus enhancing the transition to turbulence. The four chapters of this book present a thorough introduction to the field of turbulent combustion. After an overview of modeling approaches, the three remaining chapters consider the three distinct cases of premixed, non-premixed, and partially premixed combustion, respectively. This book will be of value to researchers and students of engineering and applied mathematics by demonstrating the current theories of turbulent combustion within a unified presentation of the field.
Download or read book Scramjet Combustor Simulations Using Reduced Chemical Kinetics for Practical Fuels written by and published by . This book was released on 2003 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report covers work performed to make hydrocarbon combustion modeling simulations for scramjet flow fields practical. Several approaches were combined and demonstrated to greatly improve the time required for simulating complex hydrocarbon combustion reactions in scramjet-type flows. A code that converts a large set of reactions to a FORTRAN subroutine that computes reaction rates for a reduced set of species was refined and applied. An efficient methodology for storing and reusing reaction rate computations via a multidimensional adaptive table was developed and applied. A methodology for limiting reaction rates based on fine scale molecular mixing was incorporated into the tabular methodology and applied. A code for evaluating the impact of subgrid scale nonuniformity in temperature and species on reaction rate was also developed.
Download or read book Scramjet Propulsion written by Dora Musielak and published by John Wiley & Sons. This book was released on 2023-01-10 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scramjet Propulsion Explore the cutting edge of HAP technologies with this comprehensive resource from an international leader in her field Scramjet Propulsion: A Practical Introduction delivers a comprehensive treatment of hypersonic air breathing propulsion and its applications. The book covers the most up-to-date hypersonic technologies, like endothermic fuels, fuel injection and flameholding systems, high temperature materials, and TPS, and offers technological overviews of hypersonic flight platforms like the X-43A, X-51A, and HiFIRE. It is organized around easy-to-understand explanations of technical challenges and provides extensive references for the information contained within. The highly accomplished author provides readers with a fulsome description of the theoretical underpinnings of hypersonic technologies, as well as critical design and technology issues affecting hypersonic air breathing propulsion technologies. The book’s combination of introductory theory and advanced instruction about individual hypersonic engine components is ideal for students and practitioners in fields as diverse as hypersonic vehicle and propulsion development for missile defense technologies, launch aerospaceplanes, and civilian transports. Over 250 illustrations and tables round out the material. Readers will also learn from: A thorough introduction to hypersonic flight, hypersonic vehicle concepts, and a review of fundamental principles in hypersonic air breathing propulsion Explorations of the aerothermodynamics of scramjet engines and the design of scramjet components, as well as hypersonic air breathing propulsion combustors and fuels Analyses of dual-mode combustion phenomena, materials structures, and thermal management in hypersonic vehicles, and combined cycle propulsion An examination of CFD analysis, ground and flight testing, and simulation Perfect for researchers and graduate students in aerospace engineering, Scramjet Propulsion: A Practical Introduction is also an indispensable addition to the libraries of engineers working on hypersonic vehicle development seeking a state-of-the-art resource in one of the most potentially disruptive areas of aerospace research today.
Download or read book Eddy Dissipation Model for Modeling of Turbulent Non premixed Combustion with Radiation Effect Using Openfoam written by Hassan Ibrahim Hassan Mohamed Kassem and published by . This book was released on 2011 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Parallel Modeling of Three Dimensional Scramjet Combustor and Comparisons with Experiment s Results written by and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper a parallel simulation of an experimental dual-mode scramjet combustor configuration is presented. Turbulence is modeled with the kappa-epsilon two-equation turbulence model and a 7-species 8-equation kinetics model is used to model hydrogen/air combustion. The conservation from of the Navier-Stokes equations with finite-rate chemistry reactions is solved using a diagonal implicit finite-volume method. Using about 3,12O,000 grid points the three-dimension flow-fields with equivalence ratio phi=0.0 and 0.35 have been respectively simulated on the parallel computer system obtaining more detailed flow properties than the experiment's results. Wall pressure comparisons between CFD and experiment show fair agreement. For phi=0.35 the fuel-penetrating height of the seven injectors are different because of the effects of the boundary layer and the shock wave in the combustor. According to numerical results, if adjusting the locations of the injectors the combustion efficiency could be improved.
Download or read book Subgrid Combustion Modeling for the Next Generation National Combustion Code written by and published by DIANE Publishing. This book was released on 2003 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ramjet Engines written by Mikhail Makarovich Bondari͡u︡k and published by . This book was released on 1969 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Large Eddy Simulation of Diesel Spray Combustion with Eddy Dissipation Model and CIP Methods by Use of KIVALES written by and published by . This book was released on 2007 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High fidelity Simulations and Modeling of Compressible Reacting Flows written by Amirreza Saghafian and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Scramjets are air-breathing propulsion devices and have long been recognized as suitable for hypersonic propulsion. Because of the high speed in scramjet combustors, the flow has a very short residence time before leaving the engine, during which air and fuel must mix on a molecular level and chemical reactions have to be completed. Although some ground and flight experiments have successfully demonstrated the feasibility of supersonic combustion, experimental testing requires a large investment and presents numerous difficulties. Computational tools are thus a key element toward the development of an efficient, high-performance scramjet engine, and because mixing and heat release are at the heart of a scramjet operation, the development and use of accurate combustion models for supersonic combustion are critical. The open questions in supersonic combustion span the spectrum from scientific pursuit, e.g., shock/flame interactions, to engineering applications like prediction of unstart phenomena in scramjets. In this study, direct numerical simulations (DNS) of a compressible reacting mixing layer with finite rate chemistry are performed. The DNS databases are used to explore the physics of supersonic combustion. An efficient combustion model based on the flamelet/progress variable is then introduced. In this approach, only two or three additional scalar transport equations need to be solved, independently of the complexity of the reaction mechanism. The proposed combustion model is validated using DNS databases. Finally, the compressible flamelet/progress variable model is applied to the case of an under-expanded hydrogen jet in a supersonic cross-flow and HIFiRE scramjet.
Download or read book Numerical Simulation of Scramjet Combustion in a Shock Tunnel written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Three-dimensional computational simulations of reactive flowfields within a hydrogen-fueled scramjet-like geometry experimentally tested in a free piston shock tunnel are presented. The experimental configuration (Odam and Paull, AIAA Paper 2003-5244) involves injection of hydrogen fuel into the scramjet inlet, followed by mixing, shock-induced ignition, and combustion. The predictions for both fuel-off and fuel-on conditions were observed to be sensitive to the choice of the wall temperature boundary conditions. The best comparison with experimental data were achieved through the implementation of an approach that involves a simplified conjugate heat transfer model that couples the heat conduction through the wall with the heat conduction of the fluid within the boundary layer. This approach is able to predict thermal loads on the walls of the scramjet model due to shock wave interactions and due to heat release. As such, it is able to more accurately represent the physical temperature response of the engine model. Also shown to produce very good agreement with the statistically-steady experimental data was the isothermal ghost-cell boundary condition, which is based on a simplification of the time-dependent conjugate heat transfer boundary condition. This simplified boundary condition assumes a linear temperature distribution within the wall based on the effective depth that an applied heat load would penetrate, thus, it also allows the actual wall temperature to vary in response to the applied heat load. Results for fuel-off simulations showed that the solution generated by a steady-state simulation implementing the isothermal ghost-cell wall boundary condition was very comparable with the statistically-steady solution obtained from a fully transient simulation with coupled heat conduction within the walls. When integrated in a fully time-accurate manner, the fuel-on simulations showed a striking sensitivity to the modeled rate of air ingestion into the engine. F.
Download or read book Combustion in High Speed Flows written by John Buckmaster and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 639 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the proceedings of the Workshop on Com bustion, sponsored by the Institute for Computer Applications in Science and Engineering (ICASE) and the NASA Langley Research Center (LaRC). It was held on October 12-14, 1992, and was the sec ond workshop in the series on the subject. The first was held in 1989, and its proceedings were published by Springer-Verlag under the title "Major Research Topics in Combustion," edited by M. Y. Hussaini, A. Kumar, and R. G. Voigt. The focus of the second workshop was directed towards the development, analysis, and application of basic models in high speed propulsion of particular interest to NASA. The exploration of a dual approach combining asymptotic and numerical methods for the analysis of the models was particularly encouraged. The objectives of this workshop were i) the genesis of models that would capture or reflect the basic pllysical phenomena in SCRAMJETs and/or oblique detonation-wave engines (ODWE), and ii) the stimulation of a greater interaction between NASA exper imental research community and the academic community. The lead paper by D. Bushnell on the status and issues of high speed propulsion relevant to both the SCRAMJET and the ODWE parallels his keynote address which set the stage of the workshop. Following the lead paper were five technical sessions with titles and chairs: Experiments (C. Rogers), Reacting Free Shear Layers (C. E. Grosch), Detonations (A. K. Kapila), Ignition and Struc ture (J. Buckmaster), and Unsteady Behaviour ('1'. L. Jackson).
