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Publisher:
ISBN:
Category :
Languages : en
Pages : 20

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Author: David Owen Lignell
Publisher:
ISBN:
Category : Combustion engineering
Languages : en
Pages : 470

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Author: Santanu De
Publisher: Springer
ISBN: 9811074100
Category : Science
Languages : en
Pages : 663

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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.

Author: Jochen Fröhlich
Publisher: Springer
ISBN: 3319144480
Category : Technology & Engineering
Languages : en
Pages : 656

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This volume reflects the state of the art of numerical simulation of transitional and turbulent flows and provides an active forum for discussion of recent developments in simulation techniques and understanding of flow physics. Following the tradition of earlier DLES workshops, these papers address numerous theoretical and physical aspects of transitional and turbulent flows. At an applied level it contributes to the solution of problems related to energy production, transportation, magneto-hydrodynamics and the environment. A special session is devoted to quality issues of LES. The ninth Workshop on 'Direct and Large-Eddy Simulation' (DLES-9) was held in Dresden, April 3-5, 2013, organized by the Institute of Fluid Mechanics at Technische Universität Dresden. This book is of interest to scientists and engineers, both at an early level in their career and at more senior levels.

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Category :
Languages : en
Pages : 20

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ISBN:
Category :
Languages : en
Pages : 9

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Author: Abhishek Jain
Publisher:
ISBN:
Category :
Languages : en
Pages :

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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.

Author: Henning Bockhorn
Publisher: Springer Science & Business Media
ISBN: 3642851673
Category : Science
Languages : en
Pages : 595

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Book Description
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:

Author:
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Category :
Languages : en
Pages :

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Author:
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Category :
Languages : en
Pages : 0

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Studies of soot formation in turbulent jet flames burning ethylene in air were studied for Reynolds numbers ranging from 4,000 to 23,000. Laser-based techniques were used to measure the soot volume fraction, particle size and number density as well as the temperature and relative concentration of hydroxyl radicals and polycyclic aromatic hydrocarbons. Measurements of the characteristics length scales for the soot and hydroxyl radical fields throughout the turbulent flames were obtained. The maximum soot eddy size was observed to be 7 mm or about three times the size of the diameter of the fuel jet (d= 2.18 mm). The soot eddy size increased linearly along the centerline of the turbulent flame until the mid-point, where it leveled off and finally decreased in the oxidation zone. In contrast, the hydroxyl radical eddy size always increased along the flame with a maximum eddy size of 12 mm for the higher Reynolds number flames. Analysis of the radial dependence of the eddy size was also determined. Relatively little radial dependence in the eddy size was observed for the soot particles indicating that the soot eddies moved off the axis very fast as compared to the mixing rate. However for the hydroxyl radicals, the eddy size was always larger off the axis of the flame except near the flame tip. With respect to the temperature field, temperature probability density functions indicated bimodality at all axially locations. With respect to soot formation, the highest soot formation location and the peak mean temperature were observed on the fuel-rich side of the stoichiometric flame location while the peak hydroxyl radical concentration was on the fuel-lean side.