Download or read book Computational and Experimental Investigation of Flow and Combustion Physics in Porous Media written by Sadaf Sobhani and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As emission regulations become increasingly more stringent and policies evolve to combat global climate change impacts, reducing pollutant and greenhouse gas emissions emerge as one of the most important goals of combustion research. Techniques such as staged combustion, lean premixed combustion, catalytic combustion, and advanced mixing and fuel atomization are some of the methods examined to reduce emissions of pollutants such as nitrogen oxides (NOx), carbon monoxide (CO), and unburned hydrocarbons (UHCs). Porous media combustion represents an advanced combustion concept that is capable of achieving low emissions, enhanced flame stabilization, and improved fuel efficiency. Conventionally, Porous Media Burners (PMBs) utilize a two-zone ``step" burner design, which operates on the principal that the upstream high pore-density region serves as a flame arrestor and flame stability is observed at the interface between the two regions of high and low pore density. This dissertation contributes to the analysis of combustion in porous media, characterization of its performance in conventional PMBs, and the development and testing of a novel porous matrix design for enhanced combustion performance. First, a characterization of the combustion stability, pressure drop and pollutant emissions of conventional two-zone ``step" PMB is presented for a range of operating conditions and burner designs. Long-term material durability tests at steady-state and cycled on-off conditions were performed under operation with methane-fuel at atmospheric pressure. Thermocouple temperature measurements and pressure drop data are presented and compared to results obtained from 1D volume-averaged simulations. Additionally, the burner design with the maximum combustion stability regime was identified and tested in subsequent high-pressure experiments at 2, 8, and 20 bar with fully vaporized and preheated n-heptane and methane fuels, at fuel-lean equivalence ratios. Second, in an effort to expand the combustion stability regime beyond the capability of two-zone ``step" PMBs, a novel burner design having a spatially graded porous matrix is proposed, resulting from the theoretical analysis of the governing equations and constitutive relations. This analysis reveals the significance of the pore topology on interphase heat exchange and radiative heat transfer properties, quantified by the local Stanton number and optical depth, respectively. Gradation in topology (i.e. porosity, pore diameter, cell diameter, etc.) enables the flame to stabilize dynamically within the porous matrix and for a wider range of operating conditions. Computational stability maps, temperature profiles, and emissions data are presented for comparable two-zone ``step'' and ``graded" burner concepts, which predict significant performance enhancements in the latter. The theoretical and computational investigation of matrix gradation in PMBs as well as experiments reveal the potential for tailoring the internal heat transfer properties to optimize performance, and thus motivates the subsequent work in leveraging recent advancements in additive manufacturing to enable smoothly graded porous structures. The next part of this dissertation achieves the use of Lithography-based Ceramic Manufacturing for the fabrication of functionally graded matrix structures, designed using periodic surface equations. The manufactured samples were operated in a PMB over a range of operating conditions to test the feasibility and performance of additive manufactured materials in PMBs. Thermal and durability testing of the manufactured parts are characterized, along with combustion stability maps from the ``step" and ``graded" PMB experiment, which, consistent with the previous theoretical, computational, and experimental results, show significant performance improvements of the ``graded" burner.
Download or read book Lattice Boltzmann Modeling of Complex Flows for Engineering Applications written by Andrea Montessori and published by Morgan & Claypool Publishers. This book was released on 2018-02-20 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nature continuously presents a huge number of complex and multi-scale phenomena, which in many cases, involve the presence of one or more fluids flowing, merging and evolving around us. Since its appearance on the surface of Earth, Mankind has tried to exploit and tame fluids for their purposes, probably starting with Hero's machinery to open the doors of the Temple of Serapis in Alexandria to arrive to modern propulsion systems and actuators. Today we know that fluid mechanics lies at the basis of countless scientific and technical applications from the smallest physical scales (nanofluidics, bacterial motility, and diffusive flows in porous media), to the largest (from energy production in power plants to oceanography and meteorology). It is essential to deepen the understanding of fluid behaviour across scales for the progress of Mankind and for a more sustainable and efficient future. Since the very first years of the Third Millennium, the Lattice Boltzmann Method (LBM) has seen an exponential growth of applications, especially in the fields connected with the simulation of complex and soft matter flows. LBM, in fact, has shown a remarkable versatility in different fields of applications from nanoactive materials, free surface flows, and multiphase and reactive flows to the simulation of the processes inside engines and fluid machinery. LBM is based on an optimized formulation of Boltzmann's Kinetic Equation, which allows for the simulation of fluid particles, or rather quasi-particles, from a mesoscopic point of view thus allowing the inclusion of more fundamental physical interactions in respect to the standard schemes adopted with Navier-Stokes solvers, based on the continuum assumption. In this book, the authors present the most recent advances of the application of the LBM to complex flow phenomena of scientific and technical interest with particular focus on the multi-scale modeling of heterogeneous catalysis within nano-porous media and multiphase, multicomponent flows.
Download or read book Experimental Investigation of Two Phase Flow in Porous Media effects of Surfactants on Immiscible Displacement Processes at the Pore Network Scale written by Yanping Ren and published by . This book was released on 2004 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Numerical and CFD Investigation Into the Heat Transfer and Flow Characteristics in Porous Media Using a Thermal Non Equilibrium Model written by and published by . This book was released on 2005 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heat transfer and fluid flow through porous media was investigated using numerical simulations and experiment. For the numerical simulations, two models were created. The first consisted of a two-dimensional numerical model created in MathCAD and was solved using the finite difference approach. The MathCAD model's flow in the porous media was described by the Brinkman-Forchheimer-extended Darcy equation. The second model consisted of a computational fluid dynamics (CFD) porous media model using Fluent and was solved using the finite volume approach. Both models assumed constant fluid phase and properties. Pore diameters were held constant for each simulation; two different porosities were investigated. Boundary conditions were applied at the wall in which the temperatures of the fluid and the porous media were determined by coupled energy equations. The effects of the boundary condition, the Reynolds number, porosity, and heat input were examined.
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 Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Computational Evaluation of Flow Through Porous Media written by Dimpho Millicent Mothibi and published by LAP Lambert Academic Publishing. This book was released on 2011-08 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: The understanding and quantitative description of fluid flow through porous media, is a science which has been going on for many years and investigated in a variety of disciplines. Studies in this field have primarily been based on models, which can either be described as empirical or theoretical. Part of the current study is to understand fluid flow in porous media through studying three recent theoretical pore-scale models based on the concept of a Representative Unit Cell (RUC), to represent a porous medium. Amongst other assumptions, these models assumed plane Poiseuille flow throughout each pore section of a rectangular RUC. The main objective of this study is to numerically verify this assumption using Computational Fluid Dynamics (CFD) software, FLUENT version 6.2.16. Attention is also paid to comparison between these models with the experimental data, obtained during the model tests of airflow through a timber stack end, undertaken in a wind tunnel. The laminar and intermediate airflow through a timber stack end is simulated using the commercial software FLUENT, and the results are validated against the theoretical pore-scale models and experimental data.
Download or read book Handbook of Research on Aspects and Applications of Incompressible and Compressible Aerodynamics written by Kumar, Sathish K. and published by IGI Global. This book was released on 2022-06-24 with total page 429 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerodynamics is a science that improves the ability to understand theoretical basics and apply fundamental physics in real-life problems. The study of the motion of air, both externally over an airplane wing and internally over a scramjet engine intake, has acknowledged the significance of studying both incompressible and compressible flow aerodynamics. The Handbook of Research on Aspects and Applications of Incompressible and Compressible Aerodynamics discusses all aspects of aerodynamics from application to theory. It further presents the equations and mathematical models used to describe and characterize flow fields as well as their thermodynamic aspects and applications. Covering topics such as airplane configurations, hypersonic vehicles, and the parametric effect of roughness, this premier reference source is an essential resource for engineers, scientists, students and educators of higher education, military experts, libraries, government officials, researchers, and academicians.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1985 with total page 888 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Scientific and Technical Publications written by and published by . This book was released on 1993 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Porous Media written by Kambiz Vafai and published by CRC Press. This book was released on 2005-03-30 with total page 771 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last three decades, advances in modeling flow, heat, and mass transfer through a porous medium have dramatically transformed engineering applications. Comprehensive and cohesive, Handbook of Porous Media, Second Edition presents a compilation of research related to heat and mass transfer including the development of practical applications
Download or read book Experimentation Modeling and Computation in Flow Turbulence and Combustion written by Jean-Antoine Désidéri and published by . This book was released on 1996 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 2 of this significant work presents previously unpublished cutting-edge lectures from the Third French-Russian Workshop on Fluid Dynamics held in Tashkent in April 1995. Reflecting the Workshop?s main themes, this book particularly focuses on: expermental investigation of unsteady separated flow, 3D configurations, laminar and transitional flows, turbulent shock, shock interaction in hypersonic flow, pressure pulsation in separated flows and jets and high enthalpy flows using wind tunnels. modeling of free surface flows, natural gas combustion, vortical gas flows and acoustic processes in complex channels, non-equilibrium hypersonic viscous flows, wall law for fluids and compressible fluid jets with vortex zones. theoretical predictions of aerodynamic performances with analyses of supersonic combustion, detonation, and sumulation of reactive mixing layer. solution methods for quasilinear parabolic equations and other calculations including incompressible Navier Stokes equations and parabolic equations by Monte-Carlo methods. numerical algorithms for the simulation of atmospheric gas dynamics, kinetic schemes for viscous gas dynamic flows and evolutionary algorithms for complex optimization problems. This book will be of particular interest to all engineers and research scientists in Fluid Dynamics, Aeronautics, Aerospace and Mechanical or Applied Mathematics.
Download or read book NASA Scientific and Technical Publications A Catalog of Special Publications Reference Publications Conference Publications and Technical Papers 1991 1992 written by and published by . This book was released on 1993 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analytical and experimental study of combustion in porous inert media written by Pei-Feng Hsu and published by . This book was released on 1991 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Study of Boiling Flow Through Porous Media written by John Ralph McDonald and published by . This book was released on 1970 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Essentials of Heat and Fluid Flow in Porous Media written by Arunn Narasimhan and published by Springer. This book was released on 2022-07-09 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook provides a general overview of porous media flow, and introduces various theoretical tools to characterize and predict the flow. It has been written for graduate and advanced graduate students in various engineering disciplines. It includes the topics such as fluid flow, conduction, convection, and radiation in porous media as well as porous medium aspects of biological systems. The concepts are supported by numerous solved examples to aid self-learning in students. The textbook also contains illustrated diagrams for better understanding of the concepts. This textbook will be useful for the core course of "Flow through Porous media" for graduate and advanced graduate students in various engineering disciplines. This textbook will also serve as a refresher course for researchers who are engaged in research related to porous media flow.
Download or read book Sustaining University Program Research written by United States. National Aeronautics and Space Administration and published by . This book was released on 1969 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt:
