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Author: Ernest Don Dainty
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Author: Ernest Don Dainty
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Author: Tim C. Lieuwen
Publisher: Cambridge University Press
ISBN: 1139576836
Category : Technology & Engineering
Languages : en
Pages : 427
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Book Description
Developing clean, sustainable energy systems is a pre-eminent issue of our time. Most projections indicate that combustion-based energy conversion systems will continue to be the predominant approach for the majority of our energy usage. Unsteady combustor issues present the key challenge associated with the development of clean, high-efficiency combustion systems such as those used for power generation, heating or propulsion applications. This comprehensive study is unique, treating the subject in a systematic manner. Although this book focuses on unsteady combusting flows, it places particular emphasis on the system dynamics that occur at the intersection of the combustion, fluid mechanics and acoustic disciplines. Individuals with a background in fluid mechanics and combustion will find this book to be an incomparable study that synthesises these fields into a coherent understanding of the intrinsically unsteady processes in combustors.
Author: Woong-Sik Choi
Publisher:
ISBN:
Category : Afterburners
Languages : en
Pages :
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Book Description
In current afterburners combustion is stabilized by the high temperature, recirculating region behind bluff body flame holders, such as V-gutters. Blocking the high speed flow with bluff bodies causes a significant pressure drop, and heating the flame holder by the hot combustion product causes a thermal signature, which is a critical problem in a military jet. To reduce these problems, ignition methods using a high frequency (HF) spark discharge, or a radical jet generator (RJG) were developed. The HF discharge ignited and stabilized a flame successfully in a premixed methane-air flow. The electrical power consumption was very small compared to the combustion heat release, as long as the operating velocity was relatively low. However, a theoretical study showed that the ratio of the electrical power consumption to the heat generation by the stabilized flame increases rapidly with increasing flow velocity. For flame stabilization in a high velocity flow, the developed RJG showed much better performance than direct exposure to a plasma. The present study investigated the characteristics of a radical jet produced in a RJG and injected into a main combustor. The limits of flame stabilization by this jet was measured experimentally, and compared to those of bluff body flame holders. The flame holding performance of the radical jet was also experimentally compared to that of a thermal jet. The effect of radicals on flame stabilization was examined using CHEMKIN, and the limit of flame stabilization by the radical jet was estimated for a simple flow configuration using an approximate solution. The results suggest that the reduction of local spontaneous ignition delay time by active species in the radical jet and the longer length of a typical radical jet compared to the dimension of the recirculation zone behind a bluff body increases the maximum velocity at which a flame can be stabilized.
Author: Edgar L. Wong
Publisher:
ISBN:
Category :
Languages : en
Pages : 32
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Book Description
Author: Edgar L. Wong
Publisher:
ISBN:
Category : Flame stability
Languages : en
Pages : 30
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Book Description
Author: M. A. Hanna
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: Jean R. Hertzberg
Publisher:
ISBN:
Category :
Languages : en
Pages : 298
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Author: V. A. Mironenko
Publisher:
ISBN:
Category :
Languages : en
Pages : 13
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Book Description
In solving the problem of flame stabilization, it is necessary to consider equally both the flow structure behind the bluff bodies and the kinetics of the chemical reaction. The article demonstrates, however, that, with certain assumptions and simplifications, the blow-out characteristics of a flame holder in the form of a bluff body can be satisfactorily explained and calculated, by using the thermal theory of ignition and the theory of turbulent flow. In deriving quantitative correlations, the following assumptions were made: (1) Up to the ignition point, the velocity, temperature, and concentration distributions of the turbulent boundary layer behind the holder are in accordance with the theory of turbulent flows for nonisothermal counter flows; they are not changed by the heat release resulting from the chemical reaction, for, according to the thermal theory of ignition, during the period of ignition delay, the heat release and temperature rise are insignificant. (2) The static pressure in the boundary layer behind the holder is equal to the free-stream static pressure. An expression was derived to determine the effect on the blow-out characteristics of the combustion chamber of the physical flow parameters (pressure, flow velocity, temperature) and type of fuel. If the dependence of the length of the reverse-flow zone on the dimension and shape of flame holder are known, the effect of its geometric parameters may also be determined. (Author).
Author: F El-Mahallawy
Publisher: Elsevier
ISBN: 0080532187
Category : Science
Languages : en
Pages : 863
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Book Description
Fundamentals and Technology of Combustion contains brief descriptions of combustion fundamental processes, followed by an extensive survey of the combustion research technology. It also includes mathematical combustion modeling of the processes covering mainly premixed and diffusion flames, where many chemical and physical processes compete in complex ways, for both laminar and turbulent flows. The combustion chemistry models that validate experimental data for different fuels are sufficiently accurate to allow confident predictions of the flame characteristics. This illustrates a unique bridge between combustion fundamentals and combustion technology, which provides a valuable technical reference for many engineers and scientists. Moreover, the book gives the reader sufficient background of basic engineering sciences such as chemistry, thermodynamics, heat transfer and fluid mechanics. The combustion research and mathematical models fit between small-scale laboratory burner flames, and large-scale industrial boilers, furnaces and combustion chambers. The materials have been collected from previous relevant research and some selected papers of the authors and co-workers, which have been presented mainly in different refereed journals, international conferences and symposia, thus providing a comprehensive collection. Furthermore, the book includes some of the many recent general correlations for the characteristics of laminar, turbulent, premixed and diffusion flames in an easily usable form. The authors believe that further progress in optimizing combustion performance and reducing polluting emissions can only be treated through understanding of combustion chemistry.
Author: Prasanta Sahoo
Publisher: Springer
ISBN: 3319969684
Category : Technology & Engineering
Languages : en
Pages : 756
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Book Description
This book presents selected extended papers from The First International Conference on Mechanical Engineering (INCOM2018), realized at the Jadavpur University, Kolkata, India. The papers focus on diverse areas of mechanical engineering and some innovative trends in mechanical engineering design, industrial practices and mechanical engineering education. Original, significant and visionary papers were selected for this edition, specially on interdisciplinary and emerging areas. All papers were peer-reviewed.
