Download or read book Numerical Investigation of Multi compartment Fire Scenarios Using Large Eddy Simulation LES written by Duy Quang Le and published by . This book was released on 2016 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: The selected fire scenario corresponds to the Propagation d'un Incendie pour des Scenarios Multi-locaux Elementaires (PRISME) Integral Test 4, which is a multi-room configuration with a single pool fire burning Hydrogenated Tetra-Propylene (HTP) fuel and fully open doors. The objectives of the present study are to perform Large Eddy Simulation (LES) of a large scale fire propagating inside confined and ventilated compartments, and assess the capabilities of the present LES tool applied to a well specified fire scenario. A key part of this assessment is to determine whether FireFOAM can more accurately reproduce the flow variables in comparison to other commercially available fire solvers. FireFOAM utilizes the Eddy Dissipation Concept (EDC) for combustion, discrete ordinate method for radiation, and k equation model for the Sub Grid Scale (SGS) closure. The experimental conditions are reproduced as closely as possible in the simulation. The numerical predictions focus on transient and steady-state temperature, major species concentration, velocity, and pressure in the different rooms. Detailed comparison of the FireFOAM results are made with a Fire Dynamic Simulator (FDS) study and the available experimental data. In general, FireFOAM shows good agreement between the LES results and the experimental data for temperature, velocity, species concentration, and pressure for most compartments. However, in comparison to FDS, FireFOAM over-predicts the fuel consumption rate. The variation in the fuel consumption rate between FireFOAM and FDS is due to the differences in the formulation of the residence time in the EDC combustion model by the two numerical codes.
Download or read book Numerical Simulations of Small scale and Full scale Fire Experiments written by Daniel Pegg Wilson and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A fundamental part of fire safety engineering is dedicated to the application of numerical fire models. Accurate predictions of real-life fires are needed in scenarios related to fire growth, smoke propagation, occupant egress, and structural integrity. In the context of building safety, fire modelling tools can be used to predict the response of materials to fire situations, and are increasingly prevalent in performance based design. In the present work, heat transfer and fire simulations are created with the objective to predict the resultant fire effects of different experiments. The simulations range in complexity from algebraic finite difference models to computational fluid dynamics (CFD) calculations. For each set of simulations, numerical predictions are compared with experimental data, whenever available. FireFOAM, an open source computational fluid dynamics solver, is selected as the modelling tool of choice. In the present study, four sets of simulations are conducted based upon experimental work. Firstly, a small scale test apparatus, the cone calorimeter, is investigated. Predictions from both a finite difference model and a CFD model compare favourably to the experimental results, and it is confirmed that a 1D finite difference model is not appropriate for the experimental configuration. Secondly, a full-scale fire experiment is investigated. The CFD simulations are extended to include the effects of turbulence and combustion. Large Eddy Simulation (LES) is selected for the turbulence modelling with a one equation eddy-viscosity model. Infinitely fast chemistry is assumed, and the eddy dissipation concept (EDC) is employed where combustion is controlled by the rate of turbulent mixing. Thirdly, a two-step reaction mechanism is implemented to account for compartment fires with under-ventilated combustion and more complex fuels. Chemistry based upon Arrhenius rate constants is assumed, and the Partially Stirred Reactor (PaSR) approach is employed. Good agreement is found for species and temperature predictions, with over-prediction of carbon dioxide concentrations due to modelling the reaction rates too fast. Finally, a preliminary CFD study is carried out for a multi-compartment fire where a wall section separates two compartments. Heat transfer is found to be over-predicted through the non-degrading wall section. To enhance the capabilities of the simulations, pyrolysis is recommended to be implemented to enable modelling of representative wall sections and realistic fuel loads.
Download or read book Large Eddy Simulations of Premixed Turbulent Flame Dynamics written by Gaurav Kewlani and published by . This book was released on 2014 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: High efficiency, low emissions and stable operation over a wide range of conditions are some of the key requirements of modem-day combustors. To achieve these objectives, lean premixed flames are generally preferred as they achieve efficient and clean combustion. A drawback of lean premixed combustion, however, is that the flames are more prone to dynamics. The unsteady release of sensible heat and flow dilatation in combustion processes create pressure fluctuations which, particularly in premixed flames, can couple with the acoustics of the combustion system. This acoustic coupling creates a feedback loop with the heat release that can lead to severe thermoacoustic instabilities that can damage the combustor. Understanding these dynamics, predicting their onset and proposing passive and active control strategies are critical to large-scale implementation. For the numerical study of such systems, large eddy simulation (LES) techniques with appropriate combustion models and reaction mechanisms are highly appropriate. These approaches balance the computational complexity and predictive accuracy. This work, therefore, aims to explore the applicability of these methods to the study of premixed wake stabilized flames. Specifically, finite rate chemistry LES models that can effectively capture the interaction between different turbulent scales and the combustion fronts have been implemented, and applied for the analysis of premixed turbulent flame dynamics in laboratory-scale combustor configurations. Firstly, the artificial flame thickening approach, along with an appropriate reduced chemistry mechanism, is utilized for modeling turbulence-combustion interactions at small scales. A novel dynamic formulation is proposed that explicitly incorporates the influence of strain on flame wrinkling by solving a transport equation for the latter rather than using local-equilibrium-based algebraic models. Additionally, a multiple-step combustion chemistry mechanism is used for the simulations. Secondly, the presumed-PDF approach, coupled with the flamelet generated manifold (FGM) technique, is also implemented for modeling turbulence-combustion interactions. The proposed formulation explicitly incorporates the influence of strain via the scalar dissipation rate and can result in more accurate predictions especially for highly unsteady flame configurations. Specifically, the dissipation rate is incorporated as an additional coordinate to presume the PDF and strained flamelets are utilized to generate the chemistry databases. These LES solvers have been developed and applied for the analysis of reacting flows in several combustor configurations, i.e. triangular bluff body in a rectangular channel, backward facing step configuration, axi-symmetric bluff body in cylindrical chamber, and cylindrical sudden expansion with swirl, and their performance has been be validated against experimental observations. Subsequently, the impact of the equivalence ratio variation on flame-flow dynamics is studied for the swirl configuration using the experimental PIV data as well as the numerical LES code, following which dynamic mode decomposition of the flow field is performed. It is observed that increasing the equivalence ratio can appreciably influence the dominant flow features in the wake region, including the size and shape of the recirculation zone(s), as well as the flame dynamics. Specifically, varying the heat loading results in altering the dominant flame stabilization mechanism, thereby causing transitions across distinct- flame configurations, while also modifying the inner recirculation zone topology significantly. Additionally, the LES framework has also been applied to gain an insight into the combustion dynamics phenomena for the backward-facing step configuration. Apart from evaluating the influence of equivalence ratio on the combustion process for stable flames, the flame-flow interactions in acoustically forced scenarios are also analyzed using LES and dynamic mode decomposition (DMD). Specifically, numerical simulations are performed corresponding to a selfexcited combustion instability configuration as observed in the experiments, and it is observed that LES is able to suitably capture the flame dynamics. These insights highlight the effect of heat release variation on flame-flow interactions in wall-confined combustor configurations, which can significantly impact combustion stability in acoustically-coupled systems. The fidelity of the solvers in predicting the system response to variation in heat loading and to acoustic forcing suggests that the LES framework can be suitably applied for the analysis of flame dynamics as well as to understand the fundamental mechanisms responsible for combustion instability. KEY WORDS - large eddy simulation, LES, wake stabilized flame, turbulent premixed combustion, combustion modeling, artificially thickened flame model, triangular bluff body, backward facing step combustor, presumed-PDF model, flamelet generated manifold, axi-symmetric bluff body, cylindrical swirl combustor, particle image velocimetry, dynamic mode decomposition, combustion instability, forced response.
Download or read book International Journal of Offshore and Polar Engineering written by and published by . This book was released on 2003 with total page 680 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Solar Chimney Applications in Buildings written by Long Shi and published by Springer Nature. This book was released on with total page 209 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical and Physical Processes in Combustion written by Combustion Institute (U.S.). Eastern States Section. Fall Technical Meeting and published by . This book was released on 2001 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the International Conference on Nuclear Engineering written by and published by . This book was released on 2004 with total page 896 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Coefficients for Calculating Thermodynamic and Transport Properties of Individual Species written by Bonnie J. McBride and published by . This book was released on 1993 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulent Reacting Flows written by P.A. Libby and published by Springer. This book was released on 2014-03-12 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Principles of Combustion written by Allan T. Kirkpatrick and published by John Wiley & Sons. This book was released on 2024-11-27 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt: The new edition of a classic textbook on combustion principles and processes, covering the latest developments in fuels and applications in a student-friendly format Principles of Combustion provides clear and authoritative coverage of chemically reacting flow systems. Detailed and accessible chapters cover key combustion topics such as chemical kinetics, reaction mechanisms, laminar flames, droplet evaporation and burning, and turbulent reacting flows. Numerous figures, end-of-chapter problems, extensive reference materials, and examples of specific combustion applications are integrated throughout the text. Newly revised and expanded, Principles of Combustion makes it easier for students to absorb and master each concept covered by presenting content through smaller, bite-sized chapters. Two entirely new chapters on turbulent reacting flows and solid fuel combustion are accompanied by additional coverage of low carbon fuels such as hydrogen, natural gas, and renewable fuels. This new edition contains a wealth of new homework problems, new application examples, up-to-date references, and access to a new companion website with MATLAB files that students can use to run different combustion cases. Fully updated to meet the needs of today's students and instructors, Principles of Combustion Provides problem-solving techniques that draw from thermodynamics, fluid mechanics, and chemistry Addresses contemporary topics such as zero carbon combustion, turbulent combustion, and sustainable fuels Discusses the role of combustion emissions in climate change and the need for reducing reliance on carbon-based fossil fuels Covers a wide range of combustion application areas, including internal combustion engines, industrial heating, and materials processing Containing both introductory and advanced material on various combustion topics, Principles of Combustion, Third Edition, is an essential textbook for upper-level undergraduate and graduate courses on combustion, combustion theory, and combustion processes. It is also a valuable reference for combustion engineers and scientists wanting to better understand a particular combustion problem.
Download or read book Computational Fluid Dynamics in Fire Engineering written by Guan Heng Yeoh and published by Butterworth-Heinemann. This book was released on 2009-04-20 with total page 545 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fire and combustion presents a significant engineering challenge to mechanical, civil and dedicated fire engineers, as well as specialists in the process and chemical, safety, buildings and structural fields. We are reminded of the tragic outcomes of 'untenable' fire disasters such as at King's Cross underground station or Switzerland's St Gotthard tunnel. In these and many other cases, computational fluid dynamics (CFD) is at the forefront of active research into unravelling the probable causes of fires and helping to design structures and systems to ensure that they are less likely in the future. Computational fluid dynamics (CFD) is routinely used as an analysis tool in fire and combustion engineering as it possesses the ability to handle the complex geometries and characteristics of combustion and fire. This book shows engineering students and professionals how to understand and use this powerful tool in the study of combustion processes, and in the engineering of safer or more fire resistant (or conversely, more fire-efficient) structures.No other book is dedicated to computer-based fire dynamics tools and systems. It is supported by a rigorous pedagogy, including worked examples to illustrate the capabilities of different models, an introduction to the essential aspects of fire physics, examination and self-test exercises, fully worked solutions and a suite of accompanying software for use in industry standard modeling systems. - Computational Fluid Dynamics (CFD) is widely used in engineering analysis; this is the only book dedicated to CFD modeling analysis in fire and combustion engineering - Strong pedagogic features mean this book can be used as a text for graduate level mechanical, civil, structural and fire engineering courses, while its coverage of the latest techniques and industry standard software make it an important reference for researchers and professional engineers in the mechanical and structural sectors, and by fire engineers, safety consultants and regulators - Strong author team (CUHK is a recognized centre of excellence in fire eng) deliver an expert package for students and professionals, showing both theory and applications. Accompanied by CFD modeling code and ready to use simulations to run in industry-standard ANSYS-CFX and Fluent software
Download or read book Fires Explosions and Toxic Gas Dispersions written by Marc J. Assael and published by CRC Press. This book was released on 2010-02-23 with total page 351 pages. Available in PDF, EPUB and Kindle. Book excerpt: Today's risk analysis is a very challenging field, and a solid understanding of the calculations procedure associated with it is essential for anyone involved. Fires, Explosions, and Toxic Gas Dispersions: Effects Calculation and Risk Analysis provides an overview of the methods used to assess the risk of fires, explosions, and toxic gas dispersion
Download or read book A Gallery of Combustion and Fire written by Charles E. Baukal, Jr. and published by Cambridge University Press. This book was released on 2020-09-03 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Gallery of Combustion and Fire is the first book to provide a graphical perspective of the extremely visual phenomenon of combustion in full color. It is designed primarily to be used in parallel with, and supplement existing combustion textbooks that are usually in black and white, making it a challenge to visualize such a graphic phenomenon. Each image includes a description of how it was generated, which is detailed enough for the expert but simple enough for the novice. Processes range from small scale academic flames up to full scale industrial flames under a wide range of conditions such as low and normal gravity, atmospheric to high pressures, actual and simulated flames, and controlled and uncontrolled flames. Containing over 500 color images, with over 230 contributors from over 75 organizations, this volume is a valuable asset for experts and novices alike.
Download or read book Fire Modelling written by G. Cox and published by . This book was released on 2004 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Digest explains the methodologies being used for the computer simulation of fire. It focuses on models of the fire itself: the essentially gas phase phenomenon at the heart of any fire simulation. Numerical modelling has become increasingly attractive for those wishing to fully exploit the freedoms to achieve safe, cost effective design offered by performance based regulation. This new edition of Digest 367 supersedes the version published in 1991. It explains fire growth and spread, and the two basic types of computer simulation methodologies. These are the zonal models, and the more universal field models that use the specialist discipline of computational fluid dynamics. Two types of field model are described which employ alternative approaches using Reynolds Averaged and Large Eddy methodologies to capture the influences of turbulence. An example shows the BRE CRISP model applied to the problem of smoke spread through a two storey theatre and the evacuation of the occupants.
Download or read book Turbulent Shear Flows 8 written by Franz Durst and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 419 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains a selection of the papers presented at the Eighth Symposium on Turbulent Shear Flows held at the Technical University of Munich, 9-11 September 1991. The first of these biennial international symposia was held at the Pennsylvania State Uni versity, USA, in 1977; subsequent symposia have been held at Imperial College, London, England; the University of California, Davis, USA; the University of Karlsruhe, Ger many; Cornell University, Ithaca, USA; the Paul Sabatier University, Toulouse, France; and Stanford University, California, USA. The purpose of this series of symposia is to provide a forum for the presentation and discussion of new developments in the field of turbulence, especially as related to shear flows of importance in engineering and geo physics. From the 330 extended abstracts submitted for this symposium, 145 papers were presented orally and 60 as posters. Out of these, we have selected twenty-four papers for inclusion in this volume, each of which has been revised and extended in accordance with the editors' recommendations. The following four theme areas were selected after consideration of the quality of the contributions, the importance of the area, and the selection made in earlier volumes: - wall flows, - separated flows, - compressibility effects, - buoyancy, rotation, and curvature effects. As in the past, each section corresponding to the above areas begins with an introduction by an authority in the field that places the individual contributions in context with one another and with related research.
Download or read book Particle Image Velocimetry written by Markus Raffel and published by Springer Science & Business Media. This book was released on 2007-08-09 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: This immensely practical guide to PIV provides a condensed, yet exhaustive guide to most of the information needed for experiments employing the technique. This second edition has updated chapters on the principles and extra information on microscopic, high-speed and three component measurements as well as a description of advanced evaluation techniques. What’s more, the huge increase in the range of possible applications has been taken into account as the chapter describing these applications of the PIV technique has been expanded.
Download or read book Large Eddy Simulation for Compressible Flows written by Eric Garnier and published by Springer Science & Business Media. This book was released on 2009-08-11 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses both the fundamentals and the practical industrial applications of Large Eddy Simulation (LES) in order to bridge the gap between LES research and the growing need to use it in engineering modeling.
