Download or read book Direct Numerical Simulation of Lean Premixed Turbulent Flames at High Karlovitz Numbers Under Elevated Pressures written by Xujiang Wang and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Direct Numerical Simulations of Premixed Turbulent Flame with Variable Density written by Songwei Zhang and published by . This book was released on 1994 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aalborg Universitetsbibliotek written by and published by . This book was released on 1975 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Direct Numerical Simulation for Turbulent Reacting Flows written by Thierry Baritaud and published by Editions TECHNIP. This book was released on 1996 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
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 Direct Numerical Simulation of Turbulent Non premixed Methane air Flames written by and published by . This book was released on 1995 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent non-premixed stoichiometric methane-air flames have been studied using the direct numerical simulation approach. A global one- step mechanism is used to describe the chemical kinetics, and molecular transport is modeled with constant Lewis numbers for individual species. The effect of turbulence on the internal flame structure and extinction characteristics of methane-air flames is evaluated. The flame is wrinkled and in some regions extinguished by the turbulence, while the turbulence is weakened in the vicinity of the flame due to a combination of dilatation and a 25:1 increase in kinematic viscosity across the flame. Reignition followed by partially-premixed burning is observed in the present results. Local curvature effects are found to be important in determining the local stoichiometry of the flame, and hence, the location of the peak reaction rate relative to the stoichiometric surface. The results presented in this study demonstrate the feasibility of incorporating global-step kinetics for the oxidation of methane into direct numerical simulations of homogeneous turbulence to study the flame structure.
Download or read book Direct Numerical Simulations of Strained Laminar and Turbulent Nonpremixed Flames written by Chunsang Yoo and published by . This book was released on 2005 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Direct Numerical Simulation DNS of Premixed Turbulent V flames written by Luc Vervisch and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fundamentals of Premixed Turbulent Combustion written by Andrei Lipatnikov and published by CRC Press. This book was released on 2012-10-24 with total page 551 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lean burning of premixed gases is considered to be a promising combustion technology for future clean and highly efficient gas turbine combustors. Yet researchers face several challenges in dealing with premixed turbulent combustion, from its nonlinear multiscale nature and the impact of local phenomena to the multitude of competing models. Filling a gap in the literature, Fundamentals of Premixed Turbulent Combustion introduces the state of the art of premixed turbulent combustion in an accessible manner for newcomers and experienced researchers alike. To more deeply consider current research issues, the book focuses on the physical mechanisms and phenomenology of premixed flames, with a brief discussion of recent advances in partially premixed turbulent combustion. It begins with a summary of the relevant knowledge needed from disciplines such as thermodynamics, chemical kinetics, molecular transport processes, and fluid dynamics. The book then presents experimental data on the general appearance of premixed turbulent flames and details the physical mechanisms that could affect the flame behavior. It also examines the physical and numerical models for predicting the key features of premixed turbulent combustion. Emphasizing critical analysis, the book compares competing concepts and viewpoints with one another and with the available experimental data, outlining the advantages and disadvantages of each approach. In addition, it discusses recent advances and highlights unresolved issues. Written by a leading expert in the field, this book provides a valuable overview of the physics of premixed turbulent combustion. Combining simplicity and topicality, it helps researchers orient themselves in the contemporary literature and guides them in selecting the best research tools for their work.
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 Direct Numerical Simulation of Premixed Turbulent Combustion written by Theodoor Cornelis Treurniet and published by . This book was released on 2002 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High fidelity Computation and Modeling of Turbulent Premixed Combustion written by Yunde Su and published by . This book was released on 2020 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-fidelity simulation of turbulent premixed combustion is desirable for the design of advanced energy-efficient and environmentally-friendly combustion engines. An attractive high-fidelity simulation approach that is applicable to practical combustion problems is the large eddy simulation (LES), in which the large-scale dynamics of flame-turbulence interaction are resolved down to a filter scale while the sub-filter phenomena are modeled. Since the grid size in practical LES is typically comparable to or larger than the flame front thickness, the filtered flame front is not well resolved when the filter size is taken as the grid size. Under such a condition, the spurious propagation of the filtered flame front can occur. To overcome this challenge, the front propagation formulation (FPF) method that was originally proposed to simulate propagating reaction fronts on under-resolved grids is extended to LES of turbulent premixed combustion. The closure of the regularized Dirac delta function, which FPF uses to minimize the spurious propagation, is investigated using direct numerical simulation (DNS) data for statistically planar premixed flames propagating in homogeneous isotropic turbulence. As a key ingredient in the sub-filter flame speed model that is required for the FPF method and many other combustion models, the flame wrinkling in the DNS dataset is studied in the context of fractals. The results show that, for the flames investigated in the DNS, the fractal dimension increases with the Reynolds number and the inner cut-off scale is on the order of the flame thickness. The FPF-LES framework is validated for a non-piloted Bunsen flame in the corrugated flamelet regime and a piloted Bunsen flame in the thin reaction zone regime. In both cases, the predicted results compare reasonably well with experimental measurements, demonstrating the performance of the FPF-LES framework. In LES of the non-piloted Bunsen flame, it is found that neglecting the stretch effects can cause the flame length and radius to be clearly under-predicted, which suggests the necessity to include stretch effects in LES. It is also found that the strain rate in the stretch effect model needs to be evaluated on the unburned side of the filtered flame to avoid the artificial modification of the flame wrinkling. Finally, the FPF-LES framework is applied to an experimentally studied spark-ignition (SI) engine with the emphasis on the prediction of cycle-to-cycle variations (CCVs), which are known to limit engine performance. To capture the degree of CCVs observed in the experiments, a laminar-to-turbulent flame transition model that describes the non-equilibrium sub-filter flame speed evolution during an early stage of flame kernel growth is developed. The multi-cycle LES with the proposed flame transition model under the FPF framework is found to reproduce experimentally-observed CCVs satisfactorily. The simulation results indicate the importance of modeling the laminar-to-turbulent flame transition and the effect of turbulence on the transition process, when predicting CCVs, under certain engine conditions.
Download or read book Direct Numerical Simulations of Turbulent Lean Premixed Combustion written by and published by . This book was released on 2006 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Direct Numerical Simulation of Reversible and Irreversible Chemical Reactions in Turbulent Non premixed Flames written by N. Swaminathan and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Direct Numerical Simulation and Modelling Study of the Structures and Propagation of Partially Premixed Turbulent Flames written by and published by . This book was released on 2015 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt:
