Detailed Modeling of Soot Formation and Turbulence-radiation Interactions in Turbulent Jet Flames
Author : Ranjan S. Mehta
Publisher :
Page : pages
File Size : 13,90 MB
Release : 2008
Category :
ISBN :
Modeling and Simulation of Turbulent Combustion
Author : Santanu De
Publisher : Springer
Page : 663 pages
File Size : 46,27 MB
Release : 2017-12-12
Category : Science
ISBN : 9811074100
Book Description
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.
Radiative Heat Transfer in Turbulent Combustion Systems
Author : Michael F. Modest
Publisher : Springer
Page : 167 pages
File Size : 11,28 MB
Release : 2016-01-06
Category : Science
ISBN : 3319272918
Book Description
This introduction reviews why combustion and radiation are important, as well as the technical challenges posed by radiation. Emphasis is on interactions among turbulence, chemistry and radiation (turbulence-chemistry-radiation interactions – TCRI) in Reynolds-averaged and large-eddy simulations. Subsequent chapters cover: chemically reacting turbulent flows; radiation properties, Reynolds transport equation (RTE) solution methods, and TCRI; radiation effects in laminar flames; TCRI in turbulent flames; and high-pressure combustion systems. This Brief presents integrated approach that includes radiation at the outset, rather than as an afterthought. It stands as the most recent developments in physical modeling, numerical algorithms, and applications collected in one monograph.
Turbulent Combustion Modeling
Author : Tarek Echekki
Publisher : Springer Science & Business Media
Page : 496 pages
File Size : 34,16 MB
Release : 2010-12-25
Category : Technology & Engineering
ISBN : 9400704127
Book Description
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.
Understanding and Predicting Soot Generation in Turbulent Non-premixed Jet Flames
Author :
Publisher :
Page : 81 pages
File Size : 16,27 MB
Release : 2010
Category :
ISBN :
Book Description
This report documents the results of a project funded by DoD's Strategic Environmental Research and Development Program (SERDP) on the science behind development of predictive models for soot emission from gas turbine engines. Measurements of soot formation were performed in laminar flat premixed flames and turbulent non-premixed jet flames at 1 atm pressure and in turbulent liquid spray flames under representative conditions for takeoff in a gas turbine engine. The laminar flames and open jet flames used both ethylene and a prevaporized JP-8 surrogate fuel composed of n-dodecane and m-xylene. The pressurized turbulent jet flame measurements used the JP-8 surrogate fuel and compared its combustion and sooting characteristics to a world-average JP-8 fuel sample. The pressurized jet flame measurements demonstrated that the surrogate was representative of JP-8, with a somewhat higher tendency to soot formation. The premixed flame measurements revealed that flame temperature has a strong impact on the rate of soot nucleation and particle coagulation, but little sensitivity in the overall trends was found with different fuels. An extensive array of non-intrusive optical and laser-based measurements was performed in turbulent non-premixed jet flames established on specially designed piloted burners. Soot concentration data was collected throughout the flames, together with instantaneous images showing the relationship between soot and the OH radical and soot and PAH. A detailed chemical kinetic mechanism for ethylene combustion, including fuel-rich chemistry and benzene formation steps, was compiled, validated, and reduced. The reduced ethylene mechanism was incorporated into a high-fidelity LES code, together with a moment-based soot model and models for thermal radiation, to evaluate the ability of the chemistry and soot models to predict soot formation in the jet diffusion flame. The LES results highlight the importance of including an optically-thick radiation model to accurately predict gas temperatures and thus soot formation rates. When including such a radiation model, the LES model predicts mean soot concentrations within 30% in the ethylene jet flame.
Soot Production and Thermal Radiation from Turbulent Jet Diffusion Flames
Author :
Publisher :
Page : pages
File Size : 32,42 MB
Release : 1910
Category :
ISBN :
Book Description
The aim of this study is to advance the present capability for modelling soot production and thermal radiation from turbulent jet diffusion flames. Turbulent methane / air jet diffusion flames at atmospheric and elevated pressure are studied experimentally to provide data for subsequent model development and validation. Methane is only lightly sooting at atmospheric pressure whereas at elevated pressure the soot yield increases greatly. This allows the creation of an optically thick, highly radiating flame within a laboratory scale rig. Essential flame properties needed for model validation are measured at 1 and 3 atm. These are mean mixture fraction, mean temperature, mean soot volume fraction, and mean and instantaneous spectrally resolved radiation intensity. These two flames are modelled using the parabolic CFD code GENMIX. The combustion / turbulence interaction is modelled using the conserved scalar / laminar flamelet approach. The chemistry of methane combustion is modelled using a detailed chemistry laminar flame code. The combustion model accommodates the non-adiabatic nature of the flames through the use of multiple flamelets for each scalar. The flamelets are differentiated by the amount of radiative heat loss that is included. Flamelet selection is carried out through the solution of a balance equation for enthalpy, which includes a source term for the radiative heat loss. A new soot model has been developed and calibrated by application to a laminar flame calculation. Within the turbulent flame calculations the soot production is fully coupled to the radiative loss. This is achieved through the use of multiple flamelets for the soot source terms and the inclusion of the radiative loss from the soot (as well as the gases) in the enthalpy source. Spectral radiative emission from the flames has been modelled using the RADCAL code. Mean flame properties from the GENMIX calculations are used as an input to RADCAL.
Experiments and Numerical Simulations of Turbulent Combustion of Diluted Sprays
Author : Bart Merci
Publisher : Springer Science & Business Media
Page : 167 pages
File Size : 17,73 MB
Release : 2014-03-27
Category : Technology & Engineering
ISBN : 3319046780
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.
A Reaction Progress Variable Approach for LES of Strongly Radiating Sooty Flames
Author : Amit Kumar
Publisher :
Page : 51 pages
File Size : 48,25 MB
Release : 2007
Category :
ISBN : 9781109788556
Book Description
A reaction progress variable approach is developed for subgrid scale (SGS) modeling of non-premixed turbulent diffusion flames with soot. Two-phase state-relations are constructed using three reaction progress variables to account for the soot formulation processes and radiation heat loss. Source/sink terms for soot formulation are based on existing phenomenological models. An assumed beta PDF distribution is used for characterizing the variation of the SGS two-phase mixture fraction for Large Eddy Simulation (LES). The resulting formulation couples the combustion, soot and radiation models to provide a self-consistent methodology to close SGS turbulence-chemistry-radiation interactions. Simulations are conducted of a turbulent diffusion flame for the experimental conditions of Coppalle and Joyeux [1]. Comparisons are conducted of mean and RMS temperature, soot volume fraction to experimental data. A sensitivity study reveals the importance of turbulence-radiation interactions and the dependence of the results on modeling approximations.
Radiative Heat Transfer
Author : Michael F. Modest
Publisher : Academic Press
Page : 1018 pages
File Size : 46,4 MB
Release : 2021-10-16
Category : Science
ISBN : 032398407X
Book Description
Radiative Heat Transfer, Fourth Edition is a fully updated, revised and practical reference on the basic physics and computational tools scientists and researchers use to solve problems in the broad field of radiative heat transfer. This book is acknowledged as the core reference in the field, providing models, methodologies and calculations essential to solving research problems. It is applicable to a variety of industries, including nuclear, solar and combustion energy, aerospace, chemical and materials processing, as well as environmental, biomedical and nanotechnology fields. Contemporary examples and problems surrounding sustainable energy, materials and process engineering are an essential addition to this edition. Includes end-of-chapter problems and a solutions manual, providing a structured and coherent reference Presents many worked examples which have been brought fully up-to-date to reflect the latest research Details many computer codes, ranging from basic problem solving aids to sophisticated research tools
Radiation Turbulence Interactions in Pulverized Coal Flames
Author :
Publisher :
Page : 16 pages
File Size : 23,66 MB
Release : 1995
Category :
ISBN :
Book Description
In this paper, we introduce a methodology to characterize soot volume fraction fluctuations in turbulent diffusion flames via chaotic maps. The approach is based on the hypothesis that the fluctuations of properties in turbulent flames is deterministic in nature, rather than statistical. Out objective is to develop models to mimic these fluctuations. The models will be used eventually in comprehensive algorithms to study the true physics of turbulent flames and the interaction of turbulence with radiation. To this extent, we measured the time series of soot scattering coefficient in an ethylene diffusion flame from light scattering experiments. Following this, corresponding power spectra and delay maps were calculated. It was shown that if the data were averaged, the characteristics of the fluctuations were almost completely washed out. The psds from experiments were successfully modeled using a series of logistic maps.
