Download or read book Large Eddy Simulation of Pulverized Coal Combustion in the Context of Tabulated Chemistry written by Robert Knappstein and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Large Eddy Simulation of Pulverised Coal Combustion written by Gregor Olenik and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Laser based Investigation of Gas and Solid Fuel Combustion under Oxy Fuel Atmosphere written by Sebastian Bürkle and published by BoD – Books on Demand. This book was released on 2019-03-04 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: Oxy-fuel combustion has the potential to reduce the atmospheric CO2-emissions of fossil fuel power plants by burning gaseous or solid fuels under an atmosphere of carbon dioxide and oxygen. The combustion under oxy-fuel operating conditions, however, is accompanied by major changes in the combustion behavior. The underlying chemical and physical processes are complex and highly coupled, which impedes investigations and modeling. Since tactile and most of the optical measurement techniques fail under the sensitive and simultaneously harsh environments of oxy-fuel combustion, an optical in-situ measurement system based on tunable diode laser absorption spectroscopy is developed in this work. This system allows to investigate the thermochemical state of combustion gases with respect to the quantitative concentrations of multiple combustion-relevant gases and the gas temperature. In combination with a newly developed and applied measurement strategy, the system even allows for a measurement of the gas residence time distribution. To improve the measurement accuracy, multiple absorption line parameters are experimentally determined. The measurement system is applied to three oxy-fuel combustion systems. First, the thermochemical state of the laminar, non-premixed methane combustion under oxy-fuel atmosphere is studied. The turbulent, premixed combustion of the same fuel under air and two oxy-fuel atmospheres is studied in a 20 kWth swirled combustor. Measurements of the residence time distribution of fluids in the combustion chamber provide insights into mixing and transport properties of the flow. The thermochemical state reveals insights into the reaction progess and flow mixing. Co-firing of three different solid fuels in an assisting gas flame is investigated for a combined thermal power up to 40 kWth. Here, the char burnout of the particles is investigated. The thermochemical state of the combustion of pure torrefied biomass under air and oxy-fuel combustion atmosphere is investigated in a 60 kWth close-to-application facility and compared to equillibrium calculations.
Download or read book Large Eddy Simulation of Coal Combustion written by Fabrizio Cavallo Marincola and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book MILD Combustion Modelling Challenges Experimental Configurations and Diagnostic Tools written by Alessandro Parente and published by Frontiers Media SA. This book was released on 2021-11-26 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aerospace and Associated Technology written by Anup Ghosh and published by Taylor & Francis. This book was released on 2022-09-24 with total page 607 pages. Available in PDF, EPUB and Kindle. Book excerpt: The International Conference on Theoretical Applied Computational and Experimental Mechanics is organized every three years by the Department of Aerospace Engineering IIT Kharagpur. The conference is devoted to providing a platform for scientists and engineers to exchange their views on the latest developments in Mechanics since 1998. ICTACEM Conference is aimed at bringing together academics and researchers working in various disciplines of mechanics to exchange views as well as to share knowledge between people from different parts of the globe. The 8th ICTACEM was held from December 20-22, 2021, at the Indian Institute of Technology, Kharagpur.
Download or read book Combustion written by J. Warnatz and published by Springer Science & Business Media. This book was released on 2006-09-23 with total page 389 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a rigorous treatment of the coupling of chemical reactions and fluid flow. Combustion-specific topics of chemistry and fluid mechanics are considered and tools described for the simulation of combustion processes. This edition is completely restructured. Mathematical Formulae and derivations as well as the space-consuming reaction mechanisms have been replaced from the text to appendix. A new chapter discusses the impact of combustion processes on the atmosphere, the chapter on auto-ignition is extended to combustion in Otto- and Diesel-engines, and the chapters on heterogeneous combustion and on soot formation are heavily revised.
Download or read book Coal Combustion and Gasification written by L.Douglas Smoot and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of coal is required to help satisfy the world's energy needs. Yet coal is a difficult fossil fuel to consume efficiently and cleanly. We believe that its clean and efficient use can be increased through improved technology based on a thorough understanding of fundamental physical and chemical processes that occur during consumption. The principal objective of this book is to provide a current summary of this technology. The past technology for describing and analyzing coal furnaces and combus tors has relied largely on empirical inputs for the complex flow and chemical reactions that occur while more formally treating the heat-transfer effects. GrOWing concern over control of combustion-generated air pollutants revealed a lack of understanding of the relevant fundamental physical and chemical mechanisms. Recent technical advances in computer speed and storage capacity, and in numerical prediction of recirculating turbulent flows, two-phase flows, and flows with chemical reaction have opened new opportunities for describing and modeling such complex combustion systems in greater detail. We believe that most of the requisite component models to permit a more fundamental description of coal combustion processes are available. At the same time there is worldwide interest in the use of coal, and progress in modeling of coal reaction processes has been steady.
Download or read book Large Eddy Simulation of Premixed and Non premixed Combustion in a Stagnation Point Reverse Flow Combustor written by Satish Undapalli and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A new combustor, referred to as Stagnation Point Reverse Flow (SPRF) combustor has been developed at Georgia Tech to meet increasingly stringent emission regulations. The combustor incorporates a novel design to meet the conflicting requirements of low pollution and high efficiency in both premixed and non-premixed modes. The objective of this thesis is to perform Large Eddy Simulations (LES) on this lab-scale combustor and explain the underlying physics. To achieve this, numerical simulations are performed in both the premixed and non-premixed combustion modes. The velocity field, species field, entrainment characteristics, flame structure, emissions and mixing characteristics are then analyzed. Simulations have been carried out first for a non-reactive case and the flow features in the combustor are analyzed. Next, the simulations have been extended for the premixed reactive case by employing different sub-grid scale combustion chemistry closures - Eddy Break Up (EBU), Artificially Thickened Flame (TF) and Linear Eddy Mixing (LEM) models. Only LEMLES which is an advanced scalar approach is able to accurately predict both the velocity and species field in the combustor. The results from LEM with LES (LEMLES) using a reduced chemical mechanism have been analyzed in the premixed mode. The results showed that mass entrainment occurs along the shear layer in the combustor. The entrained mass carried products into the reactant stream and provided preheating. The product entrainment enhances the reaction rates and stabilizes the flame even at very lean conditions. These products are shown to enter into the flame through local extinction zones present on the flame surface. The flame structure is further analyzed and the combustion mode is found to be primarily in thin reaction zones. The emissions in the combustor are studied using simple global mechanisms for NOx. Computations show extremely low NOx values comparable to the measured emissions. These low emissions are shown to be primarily due to the low temperatures in the combustor. LEMLES computations are also performed with detailed chemistry to capture more accurately the flame structure. The flame in the detailed chemistry case is more sensitive to strain effects and show more extinction zones very near to the injector. LEMLES approach is also used to resolve the combustion mode in the non-premixed case. The studies indicate that mixing of fuel and air close to the injector controls the combustion process. The predictions in the near field are shown to be very sensitive to the inflow conditions. Analysis shows that fuel and air mixing occurs to lean proportions in the combustor before any burning takes place. The flame structure in the non-premixed mode is very similar to the premixed mode. Along with fuel-air mixing, the products also mix with the reactants and provide the preheating effects to stabilize the flame in the downstream region of the combustor.
Download or read book Numerical Simulation of Pulverized Coal Combustion written by Danny Messig and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Combustion written by J. Warnatz and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 309 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a rigorous treatment of the coupling of chemical reactions and fluid flow. Combustion-specific topics of chemistry and fluid mechanics are considered and tools described for the simulation of combustion processes. This edition is completely restructured. Mathematical Formulae and derivations as well as the space-consuming reaction mechanisms have been replaced from the text to appendix. A new chapter discusses the impact of combustion processes on the atmosphere, the chapter on auto-ignition is extended to combustion in Otto- and Diesel-engines, and the chapters on heterogeneous combustion and on soot formation are heavily revised.
Download or read book Probability Density Function Modeling of Turbulent Premixed Combustion and Pulverized Coal Combustion written by Michael K. Stöllinger and published by . This book was released on 2010 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of probability density function (PDF) methods for turbulent combustion simulations is very attractive because arbitrary finite-rate chemistry can be exactly taken into account. PDF methods are well developed for non-premixed turbulent combustion. However, many real flames involve a variety of mixing regimes (non-premixed, partially-premixed and premixed turbulent combustion), and the development of PDF methods for partially-premixed and premixed turbulent combustion has turned out to be a challenging task. This thesis demonstrates a promising way to overcome this problem by extending existing PDF methods to cover a variety of mixing regimes. This extension of PDF methods is done by a generalization of the standard scalar mixing time scale model to account for the fast chemical reactions that are present in premixed combustion. The suitability of the new mixing time scale model is shown by applications to several premixed turbulent Bunsen flames that cover various regimes ranging from flamelet to distributed combustion. Moreover, the combined performance of several mixing models and time scale models is investigated for a turbulent premixed flame. Motivated by the success of the PDF method in turbulent gaseous combustion, the method is extended to describe dilute dispersed turbulent gas-solid reacting flows. Such flows are found in pulverized coal combustion and entrained flow coal gasification. The solid particles are modeled by a stochastic Lagrangian method which is combined with a joint velocity-composition PDF method for the gas phase. Coal specific devolatilization and char reaction models are included in the Lagrangian particle method and models for the mass, momentum and heat exchange between the phases are proposed. To account for the radiative heat transfer, a computationally efficient radiation model is coupled to the gas and particle phase equations. The proposed approach is applied in simulations of pulverized coal combustion in a semi-industrial scale furnace and validated by comparison of simulation results with available measurements.
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:
Download or read book Air Pollution and Greenhouse Gases written by Zhongchao Tan and published by Springer. This book was released on 2014-11-03 with total page 499 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook discusses engineering principles relating to air pollution and greenhouse gases (GHGs); it focuses on engineering principles and designs of related devices and equipment for air emission control for a variety of industries such as energy, chemical, and transportation industries. The book aims primarily at senior undergraduate and graduate students in mechanical, chemical and/or environmental engineering departments; it can also be used as a reference book by technical staff and design engineers who are interested in and need to have technical knowledge in air pollution and GHGs. The book is motivated by recent rapid advances in air pollution and greenhouse gas emissions and their control technologies. In addition to classic topics related to air pollution, this book is also featured with emerging topics related to air pollution and GHGs. It covers recent advances in engineering approaches to the reduction of GHG emissions including, but are not limited to, green energy technologies and carbon sequestration and storage. It also introduces an emerging topic in air pollution, which is referred to as Nano Air Pollution. It is a growing concern in air pollution, but largely missing in similar books, likely because of recent rapid advances in nanotechnology has outpaced the advances in nano air pollution control.
Download or read book Combustion written by Irvin Glassman and published by Academic Press. This book was released on 2014-12-02 with total page 775 pages. Available in PDF, EPUB and Kindle. Book excerpt: Throughout its previous four editions, Combustion has made a very complex subject both enjoyable and understandable to its student readers and a pleasure for instructors to teach. With its clearly articulated physical and chemical processes of flame combustion and smooth, logical transitions to engineering applications, this new edition continues that tradition. Greatly expanded end-of-chapter problem sets and new areas of combustion engineering applications make it even easier for students to grasp the significance of combustion to a wide range of engineering practice, from transportation to energy generation to environmental impacts. Combustion engineering is the study of rapid energy and mass transfer usually through the common physical phenomena of flame oxidation. It covers the physics and chemistry of this process and the engineering applications—including power generation in internal combustion automobile engines and gas turbine engines. Renewed concerns about energy efficiency and fuel costs, along with continued concerns over toxic and particulate emissions, make this a crucial area of engineering. New chapter on new combustion concepts and technologies, including discussion on nanotechnology as related to combustion, as well as microgravity combustion, microcombustion, and catalytic combustion—all interrelated and discussed by considering scaling issues (e.g., length and time scales) New information on sensitivity analysis of reaction mechanisms and generation and application of reduced mechanisms Expanded coverage of turbulent reactive flows to better illustrate real-world applications Important new sections on stabilization of diffusion flames—for the first time, the concept of triple flames will be introduced and discussed in the context of diffusion flame stabilization
Download or read book Theoretical and Numerical Combustion written by Thierry Poinsot and published by R.T. Edwards, Inc.. This book was released on 2005 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introducing numerical techniques for combustion, this textbook describes both laminar and turbulent flames, addresses the problem of flame-wall interaction, and presents a series of theoretical tools used to study the coupling phenomena between combustion and acoustics. The second edition incorporates recent advances in unsteady simulation methods,
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.
