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Author : Chao He
Publisher :
ISBN 13 : 9783843931311
Total Pages : pages
Book Rating : 4.9/5 (313 download)
Download or read book Large Eddy Simulation of a Spark-ignition Engine Using Tabulated Chemistry Approach written by Chao He and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Esra Yildar
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (1 download)
Download or read book Large Eddy Simulation Of A Controlled Auto-Ignition Engine Using A Multi-dimensional Tabulated Chemistry Approach written by Esra Yildar and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Peter Janas
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (1 download)
Download or read book Large Eddy Simulation of In-cylinder Phenomena in Spark Ignition Engines written by Peter Janas and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Heinz Pitsch
Publisher :
ISBN 13 :
Total Pages : 32 pages
Book Rating : 4.3/5 (91 download)
Download or read book Large Eddy Simulation of Turbulent Combustion written by Heinz Pitsch and published by . This book was released on 2006 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the first part of this work, new models for describing sub-grid quantities in reactive LES settings were developed. These models included a new model for the sub-filter variance of a conserved scalar, a new method of filtering the G-equation, a resolution-sensitive description of the turbulent burning velocity, and a flamelet formulation valid near premixed fronts. The models were shown to offer improved predictive capability through application to experimental flames. In the second part, a new method to automatically generate skeletal kinetic mechanisms for surrogate fuels, using the directed relation graph method with error propagation, was developed. These mechanisms are guaranteed to match results obtained using detailed chemistry within a user-defined accuracy for any specified target. They can be combined together to produce adequate chemical models for surrogate fuels. A library containing skeletal mechanisms of various accuracies and domains of applicability was assembled.
Author : Samuel Kazmouz
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (119 download)
Download or read book Large-Eddy Simulations of Motored Flow and Combustion in a Stratified-Charge Direct-Injection Spark-Ignition Engine written by Samuel Kazmouz and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Stratified-charge, spray-guided, spark-ignition, direct-injection operation offers efficiency improvements to conventional engines used in light-duty vehicles. However, cycle-to-cycle variability (CCV) impedes extracting the full efficiency potential of such advanced engine operation modes. In this dissertation, multi-cycle motored and fired large-eddy simulation (LES) results of an optically-accessible single-cylinder four-valve direct-injection spark- ignition engine, called G4VDI, are presented and compared to experimental results. The main objective is to investigate the root causes of CCV in stratified-charge engines. For motored operation, four sets of 60 consecutive LES cycles, with different operating conditions, are compared with experiments. LES is able to capture the wave dynamics of the ports and the in-cylinder pressure with a difference of 0.12%-2.5%, compared to experimental results. The LES velocity fields are compared with particle-image velocimetry measurements at six cutting planes. Based on the local and volume-averaged structure and magnitude indexes, it is found that LES is able to reproduce key flow events and capture large-scale in-cylinder flow structures, especially in high tumble/swirl conditions. Using proper orthogonal decomposition, LES shows that high tumble/swirl conditions produce low CCV flow fields. CCV of in-cylinder pressure ranged between 0.13% and 0.23%. For fired operation, and using the thickened flame model (TFM), 20 consecutive LES cycles of a homogeneous-charge engine operation mode are presented followed by spray-characterization in four different ambient conditions. These results lay the foundation for two stratified-charge engine operation modes, in which 20 and 35 consecutive LES cycles are compared with experiments, respectively. TFM-LES is extended for partially premixed flames and is able to reproduce experimental in-cylinder pressure (0.5%-10%), cyclic variability (20.5%-22.7%) in global and local quantities, local fuel vapor distributions, and heat release curves for homogeneous and stratified burn. Tuning TFM to reduce the burn rate increases the tendency to produce misfires, as well as the levels of CCV. Correlation analysis done on the stratified-charge LES results suggests that the influence of the early burn on the subsequent flame development is more subtle for stratified combustion compared to homogeneous combustion, that is the local conditions at the spark plug when the flame starts propagating are more influential than the conditions at spark timing, and that the injection event creates velocity conditions which might be favorable or unfavorable for the combustion event. The main contributions of this dissertation are extending TFM to highly stratified spray combustion, showing that LES can reproduce experimentally measured flow and combustion behavior in a realistic engine, including CCV, and analyzing LES to provide new insight into CCV and misfires of stratified-charge engines.
Author : P. A. Lakshminarayanan
Publisher : Springer Nature
ISBN 13 : 9819706297
Total Pages : 678 pages
Book Rating : 4.8/5 (197 download)
Download or read book Modelling Spark Ignition Combustion written by P. A. Lakshminarayanan and published by Springer Nature. This book was released on with total page 678 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Yajuvendra Shekhawat
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (992 download)
Download or read book Large-Eddy Simulations of Motored Flow and Combustion in a Homogeneous-Charge Spark-Ignition Engine written by Yajuvendra Shekhawat and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Cycle-to-cycle variations (CCV) of flow and combustion in internal combustion engines (ICE) limit their fuel efficiency and emissions potential. Large-eddy simulation (LES) is the most practical simulation tool to understand the nature of these CCV. In this research, multi-cycle LES of a two-valve, four-stroke, spark-ignition optical engine has been performed for motored and fired operations. The LES mesh quality is assessed using a length scale resolution parameter and a energy resolution parameter. For the motored operation, two 50-consecutive-cycle LES with different turbulence models (Smagorinsky model and dynamic structure model) are compared with the experiment. The pressure comparison shows that the LES is able to capture the wave-dynamics in the intake and exhaust ports. The LES velocity fields are compared with particle-image velocimetry (PIV) measurements at three cutting planes. Based on the structure and magnitude indices, the dynamic structure model is somewhat better than the Smagorinsky model as far asthe ensemble-averaged velocity fields are concerned. The CCV in the velocity fields is assessed by proper-orthogonal decomposition (POD). The POD analysis shows that LES is able to capture the level of CCV seen in the experiment. For the fired operation, two 60-cycle LES with different combustion models (thickened flame model and coherent flame model) are compared with experiment. The in-cylinderpressure and the apparent heat release rate comparison shows higher CCV for LES compared to the experiment, with the thickened flame model showing higher CCV than the coherent flame model. The correlation analysis for the LES using thickened flame model shows that the CCV in combustion/pressure is correlated with: the tumble at the intake valve closing, the resolved and subfilter-scale kinetic energy just before spark time, and the second POD mode (shear flow near spark gap) of the velocity fields just before spark time.
Author : Antonios Triantafyllidis
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (89 download)
Download or read book Large Eddy Simulations of Spark Ignition Processes with the CMC Method written by Antonios Triantafyllidis and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Guido Künne
Publisher :
ISBN 13 : 9783863760144
Total Pages : 282 pages
Book Rating : 4.7/5 (61 download)
Download or read book Large Eddy Simulation of Premixed Combustion Using Artificial Flame Thickening Coupled with Tabulated Chemistry written by Guido Künne and published by . This book was released on 2012 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Santanu De
Publisher : Springer
ISBN 13 : 9811074100
Total Pages : 663 pages
Book Rating : 4.8/5 (11 download)
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.
Author :
Publisher :
ISBN 13 :
Total Pages : 396 pages
Book Rating : 4.:/5 (941 download)
Download or read book Large-eddy Simulations of Direct-injection Spark-ignition Engine Spray and Flow Variability written by and published by . This book was released on 2015 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cycle-to-cycle variations (CCVs) in engines limit the ability of engine designers to reach the theoretical limits of engine efficiency. This study investigates CCVs in Direct-injection Spark-ignition (DISI) engines through Large-eddy Simulations (LES). Multi-cycle simulations of motored engine flow and spray simulations with variable boundary conditions were performed. The Dynamic Structure turbulence model, which is an advanced 1-equation non-viscosity turbulence model, was used to enable coarser, engineering type meshes and reasonable computational requirements. Multi-cycle motored engine simulations were run for an optical engine at several different engine operating conditions. Comparisons included both pressure and velocity measurements using Particle Image Velocimetry (PIV). Simulations were run using computational domains that either did or did not include intake and exhaust mixing plenums. Results from runners-only and full-domain simulations were overall similar, but there were differences in specific flow structures at certain times. Changes to engine speed or manifold pressure increased flow magnitudes, even after adjusting for different mean piston speeds, but had relatively minor effects on the flow structure. A spray model adapted from diesel spray simulations is presented. The adapted models were unable to match experimental trends with changing ambient density in both liquid and vapor phases simultaneously. Two spray break-up model parameters were changed to vary as functions of ambient density, which greatly improved the vapor predictions but worsened liquid predictions. Two methods from Uncertainty Quantification (UQ) were used to test the response of the spray models to prescribed uncertainty in spray boundary conditions. The effects of having uncertainty in two numerical model parameters and two physical boundary conditions was examined. Overall simulation uncertainty was much larger than the experimental uncertainty. Further tests showed the uncertainty in the simulation response variables was due primarily to uncertainty in the numerical modeling parameters. When examining the effects of uncertainty in the physical boundary conditions alone, the resulting variability in the response variables was approximately equal to the variability in the spray measurements.
Author : Rahul Jhavar
Publisher :
ISBN 13 :
Total Pages : 154 pages
Book Rating : 4.:/5 (891 download)
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 : Colin Russell Heye
Publisher :
ISBN 13 :
Total Pages : 352 pages
Book Rating : 4.:/5 (94 download)
Download or read book Adaptive and Convergent Methods for Large Eddy Simulation of Turbulent Combustion written by Colin Russell Heye and published by . This book was released on 2014 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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. Significant effort has been made over past decades to improve accuracy and applicability of the LES approach to a wide range of flows, though the current conventions often lack consistency to the problems at hand. To this end, the two main objectives of this dissertation are to develop a dynamic transport equation-based combustion model for large- eddy simulation (LES) of turbulent spray combustion and to investigate grid- independent LES modeling for scalar mixing. Long-standing combustion modeling approaches have shown to be suc- cessful for a wide range of gas-phase flames, however, the assumptions required to derive these formulations are invalidated in the presence of liquid fuels and non-negligible evaporation rates. In the first part of this work, a novel ap- proach is developed to account for these evaporation effects and the resulting multi-regime combustion process. First, the mathematical formulation is de- rived and the numerical implementation in a low-Mach number computational solver is verified against one-dimensional and lab scale, both non-reacting and reacting spray-laden flows. In order to clarify the modeling requirements in LES for spray combustion applications, results from a suite of fully-resolved direct numerical simulations (DNS) of a spray laden planar jet flame are fil- tered at a range of length scales. LES results are then validated against two sets of experimental jet flames, one having a pilot and allowing for reduced chemistry modeling and the second requiring the use of detail chemistry with in situ tabulation to reduce the computational cost of the direct integration of a chemical mechanism. The conventional LES governing equations are derived from a low-pass filtering of the Navier-Stokes equations. In practice, the filter used to derive the LES governing equations is not formally defined and instead, it is assumed that the discretization of LES equations will implicitly act as a low-pass filter. The second part of this study investigates an alternative derivation of the LES governing equations that requires the formal definition of the filtering operator, known as explicitly filtered LES. It has been shown that decoupling the filter- ing operation from the underlying grid allows for the isolation of subfilter-scale modeling errors from numerical discretization errors. Specific to combustion modeling are the aggregate errors associated with modeling sub-filter distribu- tions of scalars that are transported by numerical impacted turbulent fields. Quantities of interest to commonly-used combustion models, including sub- filter scalar variance and filtered scalar dissipation rate, are investigated for both homogeneous and shear-driven turbulent mixing.
Author : V. Ganesan
Publisher : Universities Press
ISBN 13 : 9788173710155
Total Pages : 252 pages
Book Rating : 4.7/5 (11 download)
Download or read book Computer Simulation Of Spark-Ignition Engine Processes written by V. Ganesan and published by Universities Press. This book was released on 1996 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the theory and computer programs for the simulation of spark ignition (SI) engine processes. It starts with the fundamental concepts and goes on to the advanced level and can thus be used by undergraduates, postgraduates and Ph. D. scholars.
Author : Stavros Kassinos
Publisher : Springer Science & Business Media
ISBN 13 : 3540342346
Total Pages : 440 pages
Book Rating : 4.5/5 (43 download)
Download or read book Complex Effects in Large Eddy Simulations written by Stavros Kassinos and published by Springer Science & Business Media. This book was released on 2007-07-16 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of Large Eddy Simulations is reaching a level of maturity that brings this approach to the mainstream of engineering computations, while it opens opportunities and challenges. The main objective of this volume is to bring together leading experts in presenting the state-of-the-art and emerging approaches for treating complex effects in LES. A common theme throughout is the role of LES in the context of multiscale modeling and simulation.
Author : Fabrizio Bisetti
Publisher :
ISBN 13 :
Total Pages : 430 pages
Book Rating : 4.:/5 (34 download)
Download or read book Large-eddy Simulation and Filtered Mass Density Function Approach to Non-equilibrium Turbulent Combustion Modeling written by Fabrizio Bisetti and published by . This book was released on 2007 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Alejandro Medina
Publisher : Springer Science & Business Media
ISBN 13 : 1447152891
Total Pages : 201 pages
Book Rating : 4.4/5 (471 download)
Download or read book Quasi-Dimensional Simulation of Spark Ignition Engines written by Alejandro Medina and published by Springer Science & Business Media. This book was released on 2013-08-20 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on the simulations developed in research groups over the past years, Introduction to Quasi-dimensional Simulation of Spark Ignition Engines provides a compilation of the main ingredients necessary to build up a quasi-dimensional computer simulation scheme. Quasi-dimensional computer simulation of spark ignition engines is a powerful but affordable tool which obtains realistic estimations of a wide variety of variables for a simulated engine keeping insight the basic physical and chemical processes involved in the real evolution of an automotive engine. With low computational costs, it can optimize the design and operation of spark ignition engines as well as it allows to analyze cycle-to-cycle fluctuations. Including details about the structure of a complete simulation scheme, information about what kind of information can be obtained, and comparisons of the simulation results with experiments, Introduction to Quasi-dimensional Simulation of Spark Ignition Engines offers a thorough guide of this technique. Advanced undergraduates and postgraduates as well as researchers in government and industry in all areas related to applied physics and mechanical and automotive engineering can apply these tools to simulate cyclic variability, potentially leading to new design and control alternatives for lowering emissions and expanding the actual operation limits of spark ignition engines
