Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
A Priori Analysis Of Conditional Moment Closure Modeling Of Turbulent Soot Formation Using Direct Numerical Simulation
Download A Priori Analysis Of Conditional Moment Closure Modeling Of Turbulent Soot Formation Using Direct Numerical Simulation full books in PDF, epub, and Kindle. Read online A Priori Analysis Of Conditional Moment Closure Modeling Of Turbulent Soot Formation Using Direct Numerical Simulation ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis A-priori Analysis of Conditional Moment Closure Modeling of Turbulent Soot Formation Using Direct Numerical Simulation by :
Download or read book A-priori Analysis of Conditional Moment Closure Modeling of Turbulent Soot Formation Using Direct Numerical Simulation written by and published by . This book was released on 2007 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Turbulent Combustion Modeling by : Tarek Echekki
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.
Book Synopsis Workshop on Engineering Turbulence Modeling by :
Download or read book Workshop on Engineering Turbulence Modeling written by and published by . This book was released on 1992 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Framework for Turbulent Non-premixed Combustion Modeling in OpenFoam by : Vasu Jaganath
Download or read book A Framework for Turbulent Non-premixed Combustion Modeling in OpenFoam written by Vasu Jaganath and published by . This book was released on 2020 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion remains a critical technology for electricity generation, heating, transportation and other industrial processes. Turbulent combustion lies at the heart of many of these processes. The accurate, robust and efficient computational modeling of turbulent combustion is necessary to design clean, efficient and safe combustion devices and processes. For practical combustion problems the direct numerical simulation (DNS) of the governing equations is computationally intractable. The Reynolds averaged Navier-Stokes simulation (RANS) and large eddy simulation (LES) techniques have emerged as powerful tools to simulate turbulent reacting flows. RANS and LES methodologies require closure of the unclosed terms arising from the averaging or filtering the governing equations. Even with adequate closure, RANS and LES remain computationally infeasible for simulating many combustion processes in engineering applications, further simplifications regarding flame thickness, flow and chemical reaction time scales are required. The high Damk\"{o}hler (Da) number flames can be modeled using a reduced chemistry model. A flamelet derived reduced chemistry model like Flamelet Generated Manifolds (FGM) accounts for finite rate chemistry while it greatly simplifies the simulation of turbulent combustion as it decouples the turbulent transport and flame structure. The interaction between the turbulence and the flame front in non-premixed combustion is described by the probability density function (PDF) of the composition variables. In this work, a framework for turbulent combustion modeling is presented for both RANS and, LES with FGM reduced chemistry model. This framework consists of implementation of presumed and transported PDF models and is developed within the open source CFD software OpenFOAM. The simulation of the well-known piloted methane-air jet flames (Sandia flames) is conducted in RANS context with both presumed and transported PDF models. An "A priori" analysis is conducted based on the RANS/TPDF simulation data. The analysis quantifies the extent of errors in PPDF models, specifically errors in choice of presumed PDF, statistical independence and the number moments and cross moments considered. A new PPDF model based on the Gaussian copula approach for correlation of the composition variables is developed and analyzed. The implementation of RANS/TPDF solver incorporates robust algorithms for particle tracking, position and number control. The LES/TFDF simulation of Sandia flame D is conducted to showcase the capability of the developed framework.
Book Synopsis Multi-Scale Investigations in Soot Formation and Chemical Vapor Deposition by : Abhishek Jain
Download or read book Multi-Scale Investigations in Soot Formation and Chemical Vapor Deposition written by Abhishek Jain and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Progress is made in this thesis in understanding the complex multi-scale chemical and physical processes governing the formation of condensed phase material from gaseous species. The formation of soot through combustion and the synthesis of functional nanomaterial through chemical vapor deposition (CVD) are examined. We first attempt to characterize the sooting tendencies of alternative fuels using different techniques. A new numerical model based on modified flamelet equations is used along with a modified chemical mechanism to predict the effect of fuel molecular structure on soot yield in gasoline surrogates. These simulations provide trends on sooting behavior and are one-dimensional calculations that neglect other phenomenon that govern soot yield and distribution. To determine how other factors influence sooting behavior in laminar flames we carry out experimental and numerical studies to understand how the addition of oxygen to the oxidizer changes soot yield and distribution. Finite-rate chemistry based Direct Numerical Simulations (DNS) are carried out for a series of methane/air flames with increasing Oxygen Index (OI) using an extensively validated, semi-detailed chemical kinetic mechanism, along with an aggregate-based soot model and the results are compared with experimental measurements. It is seen that the effect of variable OI is well captured for major flame characteristics including flame heights, soot yield, and distribution by the numerical simulations when compared to the experimental data. This study is however confined to a small fuel that may not represent behavior seen in real fuels or the constituents that make up these gasoline fuels or their surrogates. Thus, we examine the effects of premixing on soot processes in an iso-octane coflow laminar flame at atmospheric pressure. Iso-octane is chosen as a higher molecular weight fuel as it is an important component of gasoline and its surrogates. Flames at different levels of premixing are investigated ranging from jet equivalence ratios of 1 (non-premixed), 24, 12, and 6. Numerical simulations are compared against experimental measurements and good agreement is seen in soot yield and soot spatial distributions with increasing levels of premixing. While the above studies for soot were carried out for laminar flames combustion devices frequently operate at conditions that lead to turbulent flow. Therefore, to understand how soot is affected by turbulence we computationally study the effects large Polycyclic Atromatic Hydrocarbons species (PAH) have on soot yield and distribution in turbulent non-premixed sooting jet flames using ethylene and and jet fuel surrogate (JP-8). The effects of large PAH on soot are highlighted by comparing the PAH profiles, soot nucleation rate, and soot volume fraction distributions obtained from both simulations for each test flame. Comparisons are also made with experiments when available and further analysis is performed to determine the cause of the observed behavior. Finally, a new multi-scale model is proposed for the computational modeling of the synthesis of functional nanomaterials using CVD. The proposed model is applied to a W(CO)6/H2Se system that has been used by researchers at Penn State to perform WSe2 crystal growth. A force-field for W/C/O/H/Se is developed and favorable agreement is seen when compared to QM data. A reaction mechanism leading from W(CO)6 and H2Se to the crystal precursor is then developed and used in a reacting flow simulation of the custom CVD chamber at Penn State. The bulk reacting flow numerical predictions show promising results for the gas-phase and precursor species, while additional work is still being performed to make the method more robust.
Book Synopsis Modeling and Direct Numerical Simulation of Particle-laden Turbulent Flows by : Ying Xu
Download or read book Modeling and Direct Numerical Simulation of Particle-laden Turbulent Flows written by Ying Xu and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis AIAA Journal by : American Institute of Aeronautics and Astronautics
Download or read book AIAA Journal written by American Institute of Aeronautics and Astronautics and published by . This book was released on 2006 with total page 958 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Investigation of Conditional Source-term Estimation Approach for Turbulent Partially Premixed Combustion Modelling by : Daniele Dovizio
Download or read book Investigation of Conditional Source-term Estimation Approach for Turbulent Partially Premixed Combustion Modelling written by Daniele Dovizio and published by . This book was released on 2015 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conditional Source-term Estimation (CSE) is a closure technique for modelling turbulent combustion phenomena. CSE uses the Conditional Moment Closure (CMC) hypothesis for closing chemical source terms: conditionally averaged chemical source terms are closed by conditional averaged scalars, which are obtained by inverting an integral equation, instead of solving transport equations (as in CMC). Since CSE has been successfully applied to both premixed and non-premixed configurations, it represents an attractive method for dealing with the more general and complex case of partially premixed combustion. The objectives of the present study are to (i) consolidate the premixed formulation of CSE through numerical simulations of a turbulent bluff body premixed flame; (ii) formulate, implement and test the Doubly conditional CSE (DCSE) in the context of partially premixed combustion; (iii) compare the DCSE predictions with well documented turbulent partially premixed flames. The canonical example of partially premixed flames is represented by turbulent lifted flames. A series of lifted turbulent jet flames is investigated in RANS by using DCSE. The DCSE calculations are successful in predicting the lift-off heights at three different conditions and reproducing many aspects of the flame structure in agreement with the experimental observations. The current results show that important aspects of the stabilization mechanism can be reproduced by the DCSE combustion model. The applicability of DCSE is further evaluated by applying this approach to a series of turbulent V-shaped flames for which experimental data is available. Premixed and stratified conditions are investigated. Overall, the agreement between numerical results and experimental findings is good, demonstrating the capability of DCSE to deal with partially premixed combustion. Future work includes implementation of CSE in LES and investigation of different fuels such as propane and biofuels.
Book Synopsis Conditional Moment Closure Methods for Turbulent Combustion Modelling by : Ahmad El Sayed
Download or read book Conditional Moment Closure Methods for Turbulent Combustion Modelling written by Ahmad El Sayed and published by . This book was released on 2013 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes the application of the first-order Conditional Moment Closure (CMC) to the autoignition of high-pressure fuel jets, and to piloted and lifted turbulent jet flames using classical and advanced CMC submodels. A Doubly-Conditional Moment Closure (DCMC) formulation is further proposed.
Book Synopsis The Conditional Moment Closure Method for Modeling Lean Premixed Turbulent Combustion by : Scott Montgomery Martin
Download or read book The Conditional Moment Closure Method for Modeling Lean Premixed Turbulent Combustion written by Scott Montgomery Martin and published by . This book was released on 2003 with total page 584 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Use of Direct Numerical Simulation Data in Turbulence Modeling by : N. N. Mansour
Download or read book The Use of Direct Numerical Simulation Data in Turbulence Modeling written by N. N. Mansour and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Numerical Analysis of Turbulent Reacting Flows in Complex Combustion Systems by : Murat Yaldizli
Download or read book Numerical Analysis of Turbulent Reacting Flows in Complex Combustion Systems written by Murat Yaldizli and published by . This book was released on 2009 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Direct Numerical Simulation of Turbulence by : Jan Gerard Wissink
Download or read book Direct Numerical Simulation of Turbulence written by Jan Gerard Wissink and published by . This book was released on 1995 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Development and Application of a Turbulence Model for a Sootblower Jet Propagating Between Recovery Boiler Superheater Platens [microform] by : Danny Santoso Tandra
Download or read book Development and Application of a Turbulence Model for a Sootblower Jet Propagating Between Recovery Boiler Superheater Platens [microform] written by Danny Santoso Tandra and published by Library and Archives Canada = Bibliothèque et Archives Canada. This book was released on 2005 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: The flow of a sootblower jet as it exits the nozzle is supersonic and turbulent. Further downstream, as the jet mixes with its surroundings, the velocity decreases while the turbulence level increases. The jet can be described using the averaged Navier-Stokes equations, the perfect gas equation of state, and a turbulence model. Among these equations, it is only the turbulence model that has not reached a mature stage of development. The inability of current turbulence models to account for the turbulent effects of the jet has been the major source of errors in sootblower jet simulations. Understanding the dynamics and characteristics of a sootblower jet as it sweeps through boiler banks and interacts with deposits is an important step in the effort to improve sootblowing strategies. It is difficult and costly to study sootblower jet flow characteristics directly in an operating boiler due to its hostile environment. A much more convenient way to study the jet flow characteristics is through a numerical simulation and laboratory experiments. The second part of this thesis deals with the application of the new model to study the performance of low pressure sootblowing and the jet characteristic as it flows between two platens. The results of the numerical simulations suggest that the jet produced by the low pressure nozzle can exert a comparable amount of force on deposits of various thicknesses and distances from the nozzle exit as the jet produced by the high pressure nozzle. In the first part of this thesis, the governing equations and a literature review, which is aimed at gaining insight from the works of other researchers in an effort to model the turbulence of high-speed jets, are presented. Several challenges associated with modeling the turbulence of a sootblower jet are identified. These challenges together with the Direct Numerical Simulation (DNS) results of Sarkar (1995) and Sinha et al (2003) were used as a guide to develop a new K-epsilon based turbulence model. The model accuracy to predict free, confined, and impinging jets has been demonstrated by its good agreement with experimental measurements. The objective of this research is to develop a numerical model that can satisfactorily describe the fluid mechanics of sootblower jet interaction with tube banks and deposits, especially in the superheater sections of the boiler where massive deposit build-up generally occurs. In conjunction with laboratory experiments, the verified model will be used to study (i) the feasibility of utilizing less valuable low pressure steam for sootblowing and (ii) the characteristics of a sootblower jet propagating between superheater platens.
Book Synopsis Turbulent Combustion by : Norbert Peters
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.
Book Synopsis Modeling of Chemical Reactions and Soot Formation in Turbulent Flows by Means of Stochastic Particle Methods by : Dirk Großschmidt
Download or read book Modeling of Chemical Reactions and Soot Formation in Turbulent Flows by Means of Stochastic Particle Methods written by Dirk Großschmidt and published by . This book was released on 2007 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Soot Formation in Combustion by : Henning Bockhorn
Download or read book Soot Formation in Combustion written by Henning Bockhorn and published by Springer Science & Business Media. This book was released on 2013-03-08 with total page 595 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soot Formation in Combustion represents an up-to-date overview. The contributions trace back to the 1991 Heidelberg symposium entitled "Mechanism and Models of Soot Formation" and have all been reedited by Prof. Bockhorn in close contact with the original authors. The book gives an easy introduction to the field for newcomers, and provides detailed treatments for the specialists. The following list of contents illustrates the topics under review:
![Download Development and Application of a Turbulence Model for a Sootblower Jet Propagating Between Recovery Boiler Superheater Platens [microform] PDF Online Free](https://books.google.com/books/content/images/frontcover/JuN6tgAACAAJ?fife=w200-h370)
