Download or read book Simulations of Injection Mixing and Combustion in Supersonic Flow Using a Hybrid RANS LES Approach written by David Michael Peterson and published by . This book was released on 2011 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Large Eddy Simulation of Supersonic Combustion with Application to Scramjet Engines written by Peter Cocks and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This work evaluates the capabilities of the RANS and LES techniques for the simulation of high speed reacting flows. These methods are used to gain further insight into the physics encountered and regimes present in supersonic combustion. The target application of this research is the scramjet engine, a propulsion system of great promise for efficient hypersonic flight. In order to conduct this work a new highly parallelised code, PULSAR, is developed. PULSAR is capable of simulating complex chemistry combustion in highly compressible flows, based on a second order upwind method to provide a monotonic solution in the presence of high gradient physics. Through the simulation of a non-reacting supersonic coaxial helium jet the RANS method is shown to be sensitive to constants involved in the modelling process. The LES technique is more computationally demanding but is shown to be much less sensitive to these model parameters. Nevertheless, LES results are shown to be sensitive to the nature of turbulence at the inflow; however this information can be experimentally obtained. The SCHOLAR test case is used to validate the reacting aspects of PULSAR. Comparing RANS results from laminar chemistry and assumed PDF combustion model simulations, the influence of turbulence-chemistry interactions in supersonic combustion is shown to be small. In the presence of reactions, the RANS results are sensitive to inflow turbulence, due to its influence on mixing. From complex chemistry simulations the combustion behaviour is evaluated to sit between the flamelet and distributed reaction regimes. LES results allow an evaluation of the physics involved, with a pair of coherent vortices identified as the dominant influence on mixing for the oblique wall fuel injection method. It is shown that inflow turbulence has a significant impact on the behaviour of these vortices and hence it is vital for turbulence intensities and length scales to be measured by experimentalists, in order for accurate simulations to be possible.
Download or read book 29th International Symposium on Shock Waves 2 written by Riccardo Bonazza and published by Springer. This book was released on 2015-07-10 with total page 822 pages. Available in PDF, EPUB and Kindle. Book excerpt: This proceedings present the results of the 29th International Symposium on Shock Waves (ISSW29) which was held in Madison, Wisconsin, U.S.A., from July 14 to July 19, 2013. It was organized by the Wisconsin Shock Tube Laboratory, which is part of the College of Engineering of the University of Wisconsin-Madison. The ISSW29 focused on the following areas: Blast Waves, Chemically Reactive Flows, Detonation and Combustion, Facilities, Flow Visualization, Hypersonic Flow, Ignition, Impact and Compaction, Industrial Applications, Magnetohydrodynamics, Medical and Biological Applications, Nozzle Flow, Numerical Methods, Plasmas, Propulsion, Richtmyer-Meshkov Instability, Shock-Boundary Layer Interaction, Shock Propagation and Reflection, Shock Vortex Interaction, Shock Waves in Condensed Matter, Shock Waves in Multiphase Flow, as well as Shock Waves in Rarefield Flow. The two Volumes contain the papers presented at the symposium and serve as a reference for the participants of the ISSW 29 and individuals interested in these fields.
Download or read book Towards a Numerical Simulation of Supersonic Mixing Combustion written by Mohammed Kamel and published by LAP Lambert Academic Publishing. This book was released on 2013 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: The design and off-design studies of the hypersonic air-breathing engines face many challenges, due to the complexity of their internal flows. The mixing and combustion processes in Supersonic-Combustion Ramjet (scramjet) engines involve complicated aerothermochemical features, such as: the interactions between shock-waves and boundary-layer, the shock induced-combustion and the recirculation zones. In this study, a numerical solver is developed and validated to be an efficient design tool capable of simulating these complicated flow features of the supersonic combustors. For the code validation, several test cases are considered to monitor the code ability to solve for the diffusive and turbulent fluxes, and the chemical source term. In addition, the code is validated by resolving the transverse sonic injection into supersonic air flow in the case of Helium injection from a flat plate, and in the case of Hydrogen injection in a single-strut scramjet engine. The effectiveness of this injection technique in mixing and flame-holding is demonstrated. The results show good agreement with the previous numerical and experimental investigations, and prove the simulator's accuracy.
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 Recent Trends in Thermal and Fluid Sciences written by Debi Prasad Mishra and published by Springer Nature. This book was released on 2022-11-04 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents select proceedings of the International Conference on Mechanical Engineering (INCOME 2021). It presents the topics related to thermal and fluid mechanics including various sources of energy. The topics covered include theoretical and practical aspects of thermal and fluid systems and thermal design of the related equipment. The book also includes latest topics such as solar energy, computational techniques, enhancement of energy storage capacity, fluid solid interaction, and hybrid energy systems. The book will be a valuable reference for beginners, researchers, and professionals interested in research, design and development in thermal and fluid sciences.
Download or read book Scramjets written by Mostafa Barzegar Gerdroodbary and published by Butterworth-Heinemann. This book was released on 2020-07-21 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scramjet engines are a type of jet engine and rely on the combustion of fuel and an oxidizer to produce thrust. While scramjets are conceptually simple, actual implementation is limited by extreme technical challenges. Hypersonic flight within the atmosphere generates immense drag, and temperatures found on the aircraft and within the engine can be much greater than that of the surrounding air. Maintaining combustion in the supersonic flow presents additional challenges, as the fuel must be injected, mixed, ignited, and burned within milliseconds. Fuel mixing, along with the configuration and positioning of the injectors and the boundary conditions, play a key role in combustion efficiency. Scramjets: Fuel Mixing and Injection Systems discusses how fuel mixing efficiency and the advantage of injection systems can enhance the performance of the scramjets. The book begins with the introduction of the supersonic combustion chamber and explains the main parameters on the mixing rate. The configuration of scramjets is then introduced with special emphasis on the main effective parameters on the mixing of fuel inside the scramjets. In addition, basic concepts and principles on the mixing rate and fuel distribution within scramjets are presented. Main effective parameters such as range of fuel concentration for the efficient combustion, pressure of fuel jet and various arrangement of jet injections are also explained. This book is for aeronautical and mechanical engineers as well as those working in supersonic combustion who need to know the effects of compressibility on combustion, of shocks on mixing and on chemical reactions, and vorticity on the flame anchoring. - Explains the main applicable approaches for enhancement of supersonic combustion engines and the new techniques of fuel injection - Shows how the interaction of main air stream with fuel injections can develop the mixing inside the scramjets - Presents results of numerical simulations and how they can be used for the development of the combustion engines
Download or read book Jet in Supersonic Crossflow written by Mingbo Sun and published by Springer. This book was released on 2019-02-18 with total page 291 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on research into jets in supersonic crossflow carried out by the authors’ team over the past 15 years, this book summarizes and presents many cutting-edge findings and analyses on this subject. It tackles the complicated mixing process of gas jets and atomization process of liquid jets in supersonic crossflow, and studies their physical mechanisms. Advanced experimental and numerical techniques are applied to further readers’ understanding of atomization, mixing, and combustion of fuel jets in supersonic crossflow, which can promote superior fuel injection design in scramjet engines. The book offers a valuable reference guide for all researchers and engineers working on the design of scramjet engines, and will also benefit graduate students majoring in aeronautical and aerospace engineering.
Download or read book Turbulent Reacting Flows and Supersonic Combustion written by C. T. Bowman and published by . This book was released on 1987 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental and computational investigation of supersonic combustion flows is in progress. The principal objective of the research is to gain a more fundamental understanding of mixing and chemical reaction in supersonic flows. The research effort comprises three inter-related elements: 1) an experimental study of mixing and combustion in a supersonic plane mixing layer; 2) development of laser-induced fluorescence techniques for time-resolved two-dimensional imaging of species concentration, temperature, velocity and pressure; and, 3) numerical simulations of compressible reacting flows. The design of the supersonic plane mixing layer was completed and the high-pressure gas storage system was installed. The pulsed lasers and camera systems, to be used for two-dimension flow field imaging, were installed and initial performance evaluations are in progress. This work has focussed on development of appropriate numerical methods for performing full-turbulence simulations of high-speed compressible flows and on the application of these methods to temporally and spatially developing compressible mixing layers. The effort to date has identified several promising numerical methods for compressible flow problems. In addition, a code was developed for compressible mixing layers, and initial simulation using this code shows interesting features, such as imbedded shock waves, in high-speed mixing layers. Keywords: Turbulent reacting flow, Laser diagnostics, Computational fluid dynamics.
Download or read book A Two Dimensional Numerical Simulation of a Supersonic Chemically Reacting Mixing Layer written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-17 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research has been undertaken to achieve an improved understanding of physical phenomena present when a supersonic flow undergoes chemical reaction. A detailed understanding of supersonic reacting flows is necessary to successfully develop advanced propulsion systems now planned for use late in this century and beyond. In order to explore such flows, a study was begun to create appropriate physical models for describing supersonic combustion, and to develop accurate and efficient numerical techniques for solving the governing equations that result from these models. From this work, two computer programs were written to study reacting flows. Both programs were constructed to consider the multicomponent diffusion and convection of important chemical species, the finite rate reaction of these species, and the resulting interaction of the fluid mechanics and the chemistry. The first program employed a finite difference scheme for integrating the governing equations, whereas the second used a hybrid Chebyshev pseudospectral technique for improved accuracy. Drummond, J. Philip Langley Research Center BOUNDARY LAYERS; CHEMICAL REACTIONS; FLUID MECHANICS; MIXING; MIXING LAYERS (FLUIDS); NUMERICAL ANALYSIS; SIMULATION; SUPERSONIC FLOW; CHEBYSHEV APPROXIMATION; COMPUTER PROGRAMS; FINITE DIFFERENCE THEORY; HYPERSONIC AIRCRAFT; SUPERSONIC COMBUSTION RAMJET ENGINES...
Download or read book Unsteady Supersonic Combustion written by Mingbo Sun and published by Springer Nature. This book was released on 2020-04-14 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the unsteady phenomena needed to understand supersonic combustion. Following an initial chapter that introduces readers to the basic concepts in and classical studies on unsteady supersonic combustion, the book highlights recent studies on unsteady phenomena, which offer insights on e.g. interactions between acoustic waves and flames, flow dominating instability, ignition instability, flame flashback, and near-blowout-limit combustion. In turn, the book discusses in detail the fundamental mechanisms of these phenomena, and puts forward practical suggestions for future scramjet design.
Download or read book Huldeblijk 1923 written by and published by . This book was released on 1923 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Study of Ing Properties of Gaseous Fuels Jets in a Premixer written by Amin Akbari and published by LAP Lambert Academic Publishing. This book was released on 2012-05 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the present work, mixing of hydrogen and methane into air is simulated using various CFD approaches. Fuel is injected either co-flowing to the air flow ( axial injection ) or perpendicular to the air flow ( radial injection ). The quality of the simulations is evaluated by comparing the numerical results with experimental measurements. Qualitative and quantitative comparisons are used to evaluate the relative accuracy of different CFD approaches to simulate the mixing characteristics. Reynolds Averaged Navier Stokes (RANS) turbulence models are utilized to model all the cases as steady turbulence models. Moreover, unsteady turbulence models, such as Unsteady RANS, and Large Eddy Simulation (LES) are used to provide information about unsteady features in selected cases. The sensitivities of numerical predictions to different RANS turbulence models as well as to different turbulent Schmidt numbers are explored.
Download or read book Annual Research Briefs written by Center for Turbulence Research (U.S.) and published by . This book was released on 2011 with total page 434 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 Journal of Propulsion and Power written by and published by . This book was released on 2008 with total page 822 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Fuel Injection on Mixing and Upstream Interactions in Supersonic Flow written by Qiuya Tu and published by . This book was released on 2013 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Simulation for shock wave/ boundary-layer interaction was conducted in Fluent for case of M=1.9 at 60% blockage by using k- RNG model with two different near wall treatments. In both cases, the shock ran out of isolator before the computation converged, this is different from experimental results. Proper actual wall friction force may have a very important effect on the computation, which needs to be evaluated.
