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Large Eddy Simulation Of Premixed Flame In Engine Based On The Multi Level Formulation And The Renormalization Group Theory
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Book Synopsis Large Eddy Simulation of Premixed-flame in Engine Based on the Multi-level Formulation and the Renormalization Group Theory by : Ken Naitoh
Download or read book Large Eddy Simulation of Premixed-flame in Engine Based on the Multi-level Formulation and the Renormalization Group Theory written by Ken Naitoh and published by . This book was released on 1992 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Computational Optimization of Internal Combustion Engines by : Yu Shi
Download or read book Computational Optimization of Internal Combustion Engines written by Yu Shi and published by Springer Science & Business Media. This book was released on 2011-06-22 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational Optimization of Internal Combustion Engines presents the state of the art of computational models and optimization methods for internal combustion engine development using multi-dimensional computational fluid dynamics (CFD) tools and genetic algorithms. Strategies to reduce computational cost and mesh dependency are discussed, as well as regression analysis methods. Several case studies are presented in a section devoted to applications, including assessments of: spark-ignition engines, dual-fuel engines, heavy duty and light duty diesel engines. Through regression analysis, optimization results are used to explain complex interactions between engine design parameters, such as nozzle design, injection timing, swirl, exhaust gas recirculation, bore size, and piston bowl shape. Computational Optimization of Internal Combustion Engines demonstrates that the current multi-dimensional CFD tools are mature enough for practical development of internal combustion engines. It is written for researchers and designers in mechanical engineering and the automotive industry.
Book Synopsis Modelling Diesel Combustion by : P. A. Lakshminarayanan
Download or read book Modelling Diesel Combustion written by P. A. Lakshminarayanan and published by Springer Nature. This book was released on 2022-01-21 with total page 419 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprehensively discusses diesel combustion phenomena like ignition delay, fuel-air mixing, rate of heat release, and emissions of smoke, particulate and nitric oxide. It enables quantitative evaluation of these important phenomena and parameters. Most importantly, it attempts to model them with constants that are independent of engine types and hence they could be applied by the engineers and researchers for a general engine. This book emphasizes the importance of the spray at the wall in precisely describing the heat release and emissions for most of the engines on and off-road. It gives models for heat release and emissions. Every model is thoroughly validated by detailed experiments using a broad range of engines. The book describes an elegant quasi-one-dimensional model for heat release in diesel engines with single as well as multiple injections. The book describes how the two aspects, namely, fuel injection rate and the diameter of the combustion bowl in the piston, have enabled meeting advanced emission, noise, and performance standards. The book also discusses the topics of computational fluid dynamics encompassing RANS and LES models of turbulence. Given the contents, this book will be useful for students, researchers and professionals working in the area of vehicle engineering and engine technology. This book will also be a good professional book for practising engineers in the field of combustion engines and automotive engineering.
Author :James H.W. Whitelaw Publisher :Springer Science & Business Media ISBN 13 :9783540426653 Total Pages :460 pages Book Rating :4.4/5 (266 download)
Book Synopsis Thermo-and Fluid-dynamic Processes in Diesel Engines by : James H.W. Whitelaw
Download or read book Thermo-and Fluid-dynamic Processes in Diesel Engines written by James H.W. Whitelaw and published by Springer Science & Business Media. This book was released on 2002-01-11 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume includes versions of papers selected from those presented at the THIESEL 2000 Conference on Thermofluidynamic Processes in Diesel Engines, held at the Universidad Politecnica de Valencia, during the period of September th th 13 to 15 , 2000. The papers are grouped into seven thematic areas: State of the Art and Prospective, Fuels for Diesel Engines, Injection System and Spray Formation, Combustion and Pollutant Formation, Modelling, Experimental Techniques, and Air Management. These areas cover most of the technologies and research strategies that may allow Light Duty and Heavy Duty Diesel engines to comply with current and forthcoming emission standards, while maintaining or improving fuel consumption. The main objectives of the conference were to bring together ideas and experience from Industry and Universities to facilitate interchange of information and to promote discussion of future research and development needs. The technical papers emphasised the use diagnostic and simulation techniques and their relationship to engineering practice and the advancement of the Diesel engine. We hope that this approach, which proved to be successful at the Conference, is reflected in this volume. We thank all those who contributed to the success of the Conference, and particularly the members of the Advisory Committee who assessed abstracts and chaired many of the technical sessions. Weare also grateful to participants who presented their work or contributed to the many discussions. Finally, the Conference benefitted from financial support from the organisations listed below and we are glad to have this opportunity to record our gratitude.
Book Synopsis 39th AIAA Aerospace Sciences Meeting and Exhibit by :
Download or read book 39th AIAA Aerospace Sciences Meeting and Exhibit written by and published by . This book was released on 2001 with total page 682 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Using Large Eddy Simulations to Study Diesel DI-HCCI Engine Flow Structure, Mixing and Combustion by : Rahul Jhavar
Download or read book Using Large Eddy Simulations to Study Diesel DI-HCCI Engine Flow Structure, Mixing and Combustion written by Rahul Jhavar and published by . This book was released on 2007 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :A. L. Kuhl Publisher :AIAA (American Institute of Aeronautics & Astronautics) ISBN 13 : Total Pages :478 pages Book Rating :4.3/5 (91 download)
Book Synopsis Dynamics of Heterogeneous Combustion and Reacting Systems by : A. L. Kuhl
Download or read book Dynamics of Heterogeneous Combustion and Reacting Systems written by A. L. Kuhl and published by AIAA (American Institute of Aeronautics & Astronautics). This book was released on 1993 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: The four companion volumes on Dynamic Aspects of Detonations and Explosion Phenomena and Dynamics of Gaseous and Heterogeneous Combustion and Reactive Systems present 111 of the 230 papers given at the Thirteenth International Colloquium on the Dynamics of Explosions and Reactive Systems held in Nagoya, Japan. These books embrace the topics of explosions, detonations, shock phenomena, and reactive flow, as well as the gasdynamic aspects of nonsteady flow in combustion systems, the fluid mechanics aspects of combustion, and diagnostic techniques. Two of the volumes, Dynamics of Gaseous Combustion (Vol. 151) and Dynamics of Heterogeneous Combustion and Reacting Systems (Vol. 152), focus on the processes of coupling the exothermic energy release with the fluid mechanics occurring in various combination processes. The other two volumes, Dynamic Aspects of Detonations (Vol. 153) and Dynamic Aspects of Explosion Phenomena (Vol. 154), address the rate processes of energy deposition in a compressible medium and the concurrent nonsteady flow as it typically occurs in explosion phenomena.
Book Synopsis A High-Order Finite-Volume Scheme for Large-Eddy Simulation of Premixed Flames on Multi-Block Cartesian Mesh by : Prabhakar Regmi
Download or read book A High-Order Finite-Volume Scheme for Large-Eddy Simulation of Premixed Flames on Multi-Block Cartesian Mesh written by Prabhakar Regmi and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Annual Index/abstracts of SAE Technical Papers by :
Download or read book Annual Index/abstracts of SAE Technical Papers written by and published by . This book was released on 1992 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Engineering Index Annual written by and published by . This book was released on 1993 with total page 2264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since its creation in 1884, Engineering Index has covered virtually every major engineering innovation from around the world. It serves as the historical record of virtually every major engineering innovation of the 20th century. Recent content is a vital resource for current awareness, new production information, technological forecasting and competitive intelligence. The world?s most comprehensive interdisciplinary engineering database, Engineering Index contains over 10.7 million records. Each year, over 500,000 new abstracts are added from over 5,000 scholarly journals, trade magazines, and conference proceedings. Coverage spans over 175 engineering disciplines from over 80 countries. Updated weekly.
Book Synopsis Large Eddy Simulations of Premixed Turbulent Flame Dynamics by : Gaurav Kewlani
Download or read book Large Eddy Simulations of Premixed Turbulent Flame Dynamics written by Gaurav Kewlani and published by . This book was released on 2014 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: High efficiency, low emissions and stable operation over a wide range of conditions are some of the key requirements of modem-day combustors. To achieve these objectives, lean premixed flames are generally preferred as they achieve efficient and clean combustion. A drawback of lean premixed combustion, however, is that the flames are more prone to dynamics. The unsteady release of sensible heat and flow dilatation in combustion processes create pressure fluctuations which, particularly in premixed flames, can couple with the acoustics of the combustion system. This acoustic coupling creates a feedback loop with the heat release that can lead to severe thermoacoustic instabilities that can damage the combustor. Understanding these dynamics, predicting their onset and proposing passive and active control strategies are critical to large-scale implementation. For the numerical study of such systems, large eddy simulation (LES) techniques with appropriate combustion models and reaction mechanisms are highly appropriate. These approaches balance the computational complexity and predictive accuracy. This work, therefore, aims to explore the applicability of these methods to the study of premixed wake stabilized flames. Specifically, finite rate chemistry LES models that can effectively capture the interaction between different turbulent scales and the combustion fronts have been implemented, and applied for the analysis of premixed turbulent flame dynamics in laboratory-scale combustor configurations. Firstly, the artificial flame thickening approach, along with an appropriate reduced chemistry mechanism, is utilized for modeling turbulence-combustion interactions at small scales. A novel dynamic formulation is proposed that explicitly incorporates the influence of strain on flame wrinkling by solving a transport equation for the latter rather than using local-equilibrium-based algebraic models. Additionally, a multiple-step combustion chemistry mechanism is used for the simulations. Secondly, the presumed-PDF approach, coupled with the flamelet generated manifold (FGM) technique, is also implemented for modeling turbulence-combustion interactions. The proposed formulation explicitly incorporates the influence of strain via the scalar dissipation rate and can result in more accurate predictions especially for highly unsteady flame configurations. Specifically, the dissipation rate is incorporated as an additional coordinate to presume the PDF and strained flamelets are utilized to generate the chemistry databases. These LES solvers have been developed and applied for the analysis of reacting flows in several combustor configurations, i.e. triangular bluff body in a rectangular channel, backward facing step configuration, axi-symmetric bluff body in cylindrical chamber, and cylindrical sudden expansion with swirl, and their performance has been be validated against experimental observations. Subsequently, the impact of the equivalence ratio variation on flame-flow dynamics is studied for the swirl configuration using the experimental PIV data as well as the numerical LES code, following which dynamic mode decomposition of the flow field is performed. It is observed that increasing the equivalence ratio can appreciably influence the dominant flow features in the wake region, including the size and shape of the recirculation zone(s), as well as the flame dynamics. Specifically, varying the heat loading results in altering the dominant flame stabilization mechanism, thereby causing transitions across distinct- flame configurations, while also modifying the inner recirculation zone topology significantly. Additionally, the LES framework has also been applied to gain an insight into the combustion dynamics phenomena for the backward-facing step configuration. Apart from evaluating the influence of equivalence ratio on the combustion process for stable flames, the flame-flow interactions in acoustically forced scenarios are also analyzed using LES and dynamic mode decomposition (DMD). Specifically, numerical simulations are performed corresponding to a selfexcited combustion instability configuration as observed in the experiments, and it is observed that LES is able to suitably capture the flame dynamics. These insights highlight the effect of heat release variation on flame-flow interactions in wall-confined combustor configurations, which can significantly impact combustion stability in acoustically-coupled systems. The fidelity of the solvers in predicting the system response to variation in heat loading and to acoustic forcing suggests that the LES framework can be suitably applied for the analysis of flame dynamics as well as to understand the fundamental mechanisms responsible for combustion instability. KEY WORDS - large eddy simulation, LES, wake stabilized flame, turbulent premixed combustion, combustion modeling, artificially thickened flame model, triangular bluff body, backward facing step combustor, presumed-PDF model, flamelet generated manifold, axi-symmetric bluff body, cylindrical swirl combustor, particle image velocimetry, dynamic mode decomposition, combustion instability, forced response.
Book Synopsis High-order Finite-volume CENO Scheme for Large-Eddy Simulation of Premixed Flames by : Luiz Tobaldini Tobaldini Neto
Download or read book High-order Finite-volume CENO Scheme for Large-Eddy Simulation of Premixed Flames written by Luiz Tobaldini Tobaldini Neto and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A novel, parallel, high-order, central essentially non-oscillatory (CENO), cell-centered, finite-volume scheme is developed and applied to large-eddy simulation (LES) of turbulent premixed flames. The high-order CENO finite-volume scheme is applied to the solution of the Favre-filtered Navier-Stokes equations governing turbulent flows of a fully compressible reactive mixture on a three-dimensional, multi-block, body-fitted, computational mesh consisting of hexahedral volume elements. The CENO method uses a hybrid reconstruction approach based on a fixed central stencil. The discretization of the inviscid fluxes combines an unlimited high-order least-squares reconstruction technique based on the optimal central stencil with a monotonicity preserving, limited, linear, reconstruction algorithm. Switching in the hybrid procedure is determined by a smoothness indicator such that the unlimited high-order reconstruction is retained for smooth solution content that is fully resolved and reverts to the limited lower-order scheme, enforcing solution monotonicity, for regions with abrupt variations (i.e., discontinuities and under-resolved regions). The high-order viscous fluxes are computed to the same order of accuracy as the hyperbolic fluxes based on a high-order accurate cell interface gradient derived from the unlimited, cell-centered, reconstruction. The proposed cell-centered finite-volume scheme is formulated for three-dimensional multi-block mesh consisting of generic hexahedral cells and applied to LES of premixed flames. For the reactive flows of interest here, a flamelet-based subfilter-scale (SFS) model is used to describe the unresolved influences of interaction between the turbulence and combustion. This SFS combustion model is based on a presumed conditional moment (PCM) approach in conjunction with flame prolongation of intrinsic low-dimensional manifold (FPI) tabulated chemistry. Numerical results are discussed for a laboratory-scale lean premixed methane-air Bunsen-type flame. The performance of the proposed high-order scheme for turbulent reactive flows is analysed by a systematic mesh refinement study using different spatial orders of accuracy.
Book Synopsis Explicit and Implicit Large Eddy Simulation of Turbulent Combustion with Multi-scale Forcing by : Song Zhao
Download or read book Explicit and Implicit Large Eddy Simulation of Turbulent Combustion with Multi-scale Forcing written by Song Zhao and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The context of this study is the optimization of premixed turbulent combustion of syngas for clean energy production. A Bunsen-type CH4/air turbulent premixed burner with a multi-scale grid generator is simulated with different Large Eddy Simulation (LES) strategies and compared to experimental results. A low-Mach formulation of a compressible Navier-Stokes solver based on different numerical methods, ranging from 4th order central finite difference to 5th order advanced WENO schemes, is developed and applied. Classical test cases (1D laminar premixed flame, decaying HIT), and 2D simulations of the turbulent premixed flame are performed to assess the numerical methodology. Implicit LES (ILES), i.e. LES without any explicit subgrid modeling, and explicit LES with the Thickened Flame model and subgrid scale flame wrinkling modelling (TFLES) are applied to simulate numerically the 3D experimental burner. Results show that TFLES with a high-order low dissipation scheme predicts quite well the experimental flame length and flame surface density. ILES with advanced WENO schemes produces a slightly shorter although realistic flame provided the grid spacing is of order of the laminar flame thickness. The representation of flame/turbulence interactions in TFLES and ILES are however quite different.
Book Synopsis Large Eddy Simulation of Premixed and Partially Premixed Combustion by : Ionuţ Porumbel
Download or read book Large Eddy Simulation of Premixed and Partially Premixed Combustion written by Ionuţ Porumbel and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Large Eddy Simulation (LES) of bluff body stabilized premixed and partially premixed combustion close to the flammability limit is carried out in this thesis. The LES algorithm has no ad-hoc adjustable model parameters and is able to respond automatically to variations in the inflow conditions. Algorithm validation is achieved by comparison with reactive and non-reactive experimental data. In the reactive flow, two scalar closure models, Eddy Break-Up (EBULES) and Linear Eddy Mixing (LEMLES), are used and compared. Over important regions, the flame lies in the Broken Reaction Zone regime. Here, the EBU model assumptions fail. The flame thickness predicted by LEMLES is smaller and the flame is faster to respond to turbulent fluctuations, resulting in a more significant wrinkling of the flame surface. As a result, LEMLES captures better the subtle effects of the flame-turbulence interaction. Three premixed (equivalence ratio = 0.6, 0.65, and 0.75) cases are simulated. For the leaner case, the flame temperature is lower, the heat release is reduced and vorticity is stronger. As a result, the flame in this case is found to be unstable. In the rich case, the flame temperature is higher, and the spreading rate of the wake is increased due to the higher amount of heat release Partially premixed combustion is simulated for cases where the transverse profile of the inflow equivalence ratio is variable. The simulations show that for mixtures leaner in the core the vortical pattern tends towards anti-symmetry and the heat release decreases, resulting also in instability of the flame. For mixtures richer in the core, the flame displays sinusoidal flapping resulting in larger wake spreading. More accurate predictions of flame stability will require the use of detailed chemistry, raising the computational cost of the simulation. To address this issue, a novel algorithm for training Artificial Neural Networks (ANN) for prediction of the chemical source terms has been implemented and tested. Compared to earlier methods, the main advantages of the ANN method are in CPU time and disk space and memory reduction.
Book Synopsis Towards Multi-cycle Simulation of In-cylinder Flow and Combustion by : Frank Freikamp
Download or read book Towards Multi-cycle Simulation of In-cylinder Flow and Combustion written by Frank Freikamp and published by Cuvillier Verlag. This book was released on 2008 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book JSME International Journal written by and published by . This book was released on 1993 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Turbulent Premixed Flames by : Nedunchezhian Swaminathan
Download or read book Turbulent Premixed Flames written by Nedunchezhian Swaminathan and published by Cambridge University Press. This book was released on 2011-04-25 with total page 447 pages. Available in PDF, EPUB and Kindle. Book excerpt: A work on turbulent premixed combustion is important because of increased concern about the environmental impact of combustion and the search for new combustion concepts and technologies. An improved understanding of lean fuel turbulent premixed flames must play a central role in the fundamental science of these new concepts. Lean premixed flames have the potential to offer ultra-low emission levels, but they are notoriously susceptible to combustion oscillations. Thus, sophisticated control measures are inevitably required. The editors' intent is to set out the modeling aspects in the field of turbulent premixed combustion. Good progress has been made on this topic, and this cohesive volume contains contributions from international experts on various subtopics of the lean premixed flame problem.
