Author: N. SwaminathanPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Direct Numerical Simulation of Reversible and Irreversible Chemical Reactions in Turbulent Non-premixed Flames
Author: N. SwaminathanDirect Numerical Simulation for Turbulent Reacting Flows
Author: Thierry BaritaudPublisher: Editions TECHNIP
ISBN: 9782710806981
Category : Science
Languages : en
Pages : 328
Book Description
Contents: Description of accurate boundary conditions for the simulation of reactive flows. Parallel direct numerical simulation of turbulent reactive flow. Flame-wall interaction and heat flux modelling in turbulent channel flow. A numerical study of laminar flame wall interaction with detailed chemistry: wall temperature effects. Modeling and simulation of turbulent flame kernel evolution. Experimental and theoretical analysis of flame surface density modelling for premixed turbulent combustion. Gradient and counter-gradient transport in turbulent premixed flames. Direct numerical simulation of turbulent flames with complex chemical kinetics. Effects of curvature and unsteadiness in diffusion flames. Implications for turbulent diffusion combustion. Numerical simulations of autoignition in turbulent mixing flows. Stabilization processes of diffusion flames. References.
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Author: Direct Numerical Simulations of Strained Laminar and Turbulent Nonpremixed Flames
Author: Chunsang YooTurbulent Premixed Flames
Author: Nedunchezhian SwaminathanPublisher: Cambridge University Press
ISBN: 1139498584
Category : Technology & Engineering
Languages : en
Pages : 447
Book Description
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.
Turbulent Combustion
Author: Norbert PetersPublisher: Cambridge University Press
ISBN: 1139428063
Category : Science
Languages : en
Pages : 322
Book Description
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.
Direct Numerical Simulations of Premixed Turbulent Flame with Variable Density
Author: Songwei ZhangAdvanced Chemistry Solver Development and Computational Diagnostics and Dynamic Adaptive Modeling of Turbulent Combustion
Author: Chao XuPublisher:
ISBN:
Category : Combustion
Languages : en
Pages : 182
Book Description
Three approaches toward efficient and predictive turbulent combustion modeling are investigated in this dissertation. The first approach focuses on the development of locally reduced chemistry and advanced solvers for efficient time integration of stiff chemical kinetic systems. In particular, a numerical technique using dynamic adaptive chemistry (DAC) with splitting schemes is developed and demonstrated in one-dimensional (1-D) premixed flames. A sparse stiff chemistry solver based on dynamic adaptive hybrid integration (AHI) and sparse matrix techniques (AHI-S), and an iterative uncoupled quasi-steady-state (IU-QSS) method for improved stability of explicit solvers, are further developed and shown to be more computationally efficient than other chemistry solvers in various flame configurations. In the second approach, a computational diagnostic tool, namely the chemical explosive mode analysis (CEMA), is extended to account for the interactions between chemical reactions and transport processes. Different local combustion modes, including the auto-ignition, diffusion-assisted ignition, and extinction modes, are demarcated by projecting the chemical and transport source terms to the chemical explosive mode. A criterion based on the local combustion modes is proposed to distinguish between two premixed flame propagation modes, that is the auto-ignition and diffusion-controlled deflagration waves, respectively. The new criterion is validated in 1-D premixed flames and 2-D homogeneous charge compression ignition (HCCI) systems. CEMA-based diagnostics are then employed to investigate the local structures of strongly turbulent premixed n-dodecane flames, and to understand the propagation modes and stabilization mechanisms of a turbulent lifted dimethyl ether (DME) jet flame, based on direct numerical simulation (DNS) data. The third approach is to construct a dynamic adaptive combustion modeling framework for turbulent flames that involve both premixed and non-premixed features. CEMA is adopted as a flame segmentation tool, and appropriate sub-models are assigned on-the-fly to different flame zones. The proposed modeling framework is tested in a turbulent lifted n-dodecane spray flame using large eddy simulations (LES). The new model is found to predict the ignition delay and lift-off length more accurately compared with the low-cost flamelet models, while the overall computational cost can be substantially reduced compared with the high-cost regime-independent models that incorporate finite rate chemistry.
Direct Numerical Simulation of Lean Premixed Turbulent Flames at High Karlovitz Numbers Under Elevated Pressures
Author: Xujiang WangExperiments and Numerical Simulations of Turbulent Combustion of Diluted Sprays
Author: Bart MerciPublisher: Springer Science & Business Media
ISBN: 3319046780
Category : Technology & Engineering
Languages : en
Pages : 167
Book Description
This book reflects the results of the 2nd and 3rd International Workshops on Turbulent Spray Combustion. The focus is on progress in experiments and numerical simulations for two-phase flows, with emphasis on spray combustion. Knowledge of the dominant phenomena and their interactions allows development of predictive models and their use in combustor and gas turbine design. Experts and young researchers present the state-of-the-art results, report on the latest developments and exchange ideas in the areas of experiments, modelling and simulation of reactive multiphase flows. The first chapter reflects on flame structure, auto-ignition and atomization with reference to well-characterized burners, to be implemented by modellers with relative ease. The second chapter presents an overview of first simulation results on target test cases, developed at the occasion of the 1st International Workshop on Turbulent Spray Combustion. In the third chapter, evaporation rate modelling aspects are covered, while the fourth chapter deals with evaporation effects in the context of flamelet models. In chapter five, LES simulation results are discussed for variable fuel and mass loading. The final chapter discusses PDF modelling of turbulent spray combustion. In short, the contributions in this book are highly valuable for the research community in this field, providing in-depth insight into some of the many aspects of dilute turbulent spray combustion.