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Author: Srivatsava Venkataranga Puranam Publisher: ISBN: 9781124149783 Category : Languages : en Pages : 176
Book Description
Thermodynamic analyses of gas turbine engine cycles have shown that adding energy in the turbine stage improves performance for both aero and stationary gas turbine systems. A curving and contracting test section with a cavity for flame holding was designed to mimic a turbine stator passage. A cavity was used for flame holding because it provided a low speed zone for mixing the fuel and air and allowed for the injection of liquid fuel into the test section. Combustion with a deep cavity (length/depth = 1) showed that for fixed fuel flow rates, as the air flow rate is increased, the combustion goes through three regimes. For very low flow rates, the combustion was confined to the shear layer and for high air flow rates, combustion was distributed through out the cavity and the shear layer and for intermediate flow rates, combustion was intermittent. A simple predictive model showed that the ratio of cavity velocity and the main flow velocity scaled as the square root of Reynolds number based on the momentum thickness. This result was corroborated by experiments. Combustion in a shallow cavity (length/depth = 2) showed that the interaction between the main low and cavity was enhanced compared to deep cavities. This enhancement was seen as a increases in the shear layer spreading rate and the fluctuation of the shear layer and as an improvement in the temperature pattern factor at the exit compared to deep cavities. Configuration changes such as injection location and direction, and cavity location had very little effect on the combustion inside the cavity. Liquid fuel combustion was qualitatively similar to the gaseous fuel case. This suggested that the controlling factor in both cases was the mixing of the fuel and air. A simple time-scale analysis which compared the mixing in the cavity and the mixing in the shear layer showed that the ratio of these time scales varies significantly for the three regimes. A novel image processing technique based on the scale invariant features in images was used to determine velocities in reacting flows where flow seeding was not possible.
Author: Srivatsava Venkataranga Puranam Publisher: ISBN: 9781124149783 Category : Languages : en Pages : 176
Book Description
Thermodynamic analyses of gas turbine engine cycles have shown that adding energy in the turbine stage improves performance for both aero and stationary gas turbine systems. A curving and contracting test section with a cavity for flame holding was designed to mimic a turbine stator passage. A cavity was used for flame holding because it provided a low speed zone for mixing the fuel and air and allowed for the injection of liquid fuel into the test section. Combustion with a deep cavity (length/depth = 1) showed that for fixed fuel flow rates, as the air flow rate is increased, the combustion goes through three regimes. For very low flow rates, the combustion was confined to the shear layer and for high air flow rates, combustion was distributed through out the cavity and the shear layer and for intermediate flow rates, combustion was intermittent. A simple predictive model showed that the ratio of cavity velocity and the main flow velocity scaled as the square root of Reynolds number based on the momentum thickness. This result was corroborated by experiments. Combustion in a shallow cavity (length/depth = 2) showed that the interaction between the main low and cavity was enhanced compared to deep cavities. This enhancement was seen as a increases in the shear layer spreading rate and the fluctuation of the shear layer and as an improvement in the temperature pattern factor at the exit compared to deep cavities. Configuration changes such as injection location and direction, and cavity location had very little effect on the combustion inside the cavity. Liquid fuel combustion was qualitatively similar to the gaseous fuel case. This suggested that the controlling factor in both cases was the mixing of the fuel and air. A simple time-scale analysis which compared the mixing in the cavity and the mixing in the shear layer showed that the ratio of these time scales varies significantly for the three regimes. A novel image processing technique based on the scale invariant features in images was used to determine velocities in reacting flows where flow seeding was not possible.
Author: Ben James Colcord Publisher: ISBN: 9781267132109 Category : Languages : en Pages : 175
Book Description
Deliberate continuation of the combustion in the turbine passages of a gas turbine engine has the potential to increase the efficiency and the specific thrust or power of current gas-turbine engines. This concept, known as a turbine-burner, must overcome many challenges before becoming a viable product. One major challenge is the injection, mixing, ignition, and burning of fuel within a short residence time in a turbine passage characterized by large three-dimensional accelerations. One method of increasing the residence time is to inject the fuel into a cavity adjacent to the turbine passage, creating a low-speed zone for mixing and combustion. This situation is simulated numerically, with the turbine passage modeled as a turning, converging channel flow of high-temperature, vitiated air adjacent to a cavity. Both two- and three-dimensional, reacting and non-reacting calculations are performed, examining the effects of channel curvature and convergence, fuel and additional air injection configurations, and inlet conditions. Two-dimensional, non-reacting calculations show that higher aspect ratio cavities improve the fluid interaction between the channel flow and the cavity, and that the cavity dimensions are important for enhancing the mixing. Two-dimensional, reacting calculations show that converging channels improve the combustion efficiency. Channel curvature can be either beneficial or detrimental to combustion efficiency, depending on the location of the cavity and the fuel and air injection configuration. Three-dimensional, reacting calculations show that injecting fuel and air so as to disrupt the natural motion of the cavity stimulates three-dimensional instability and improves the combustion efficiency.
Author: Publisher: ISBN: Category : Languages : en Pages : 28
Book Description
This theoretical/computational and experimental study addressed the vital two-way coupling between combustion processes and fluid dynamic phenomena associated with schemes for burning liquid fuels in high-speed, accelerating, and turning transonic turbulent flows. A major motivation for this type of combustion configuration was the demonstrated potential for improvements in the performance of gas turbine engines via combustion in the turbine passages. This program addressed various fundamental issues concerning combustion in an axially and centrifugally accelerating flow. The major combustion challenge involved ignition and flame-holding of a flame in the high-acceleration flow and the associated optimization of the injection of the fuel and some secondary air into a protected recirculation zone provided by a cavity. The objectives were to advance our understanding of liquid-fuel combustion in accelerating flows and thereby to contribute to the development of turbine-burner technology.
Author: Petros Koumoutsakos Publisher: Springer ISBN: 3540360859 Category : Technology & Engineering Languages : en Pages : 239
Book Description
This monograph presents the state of the art of theory and applications in fluid flow control, assembling contributions by leading experts in the field. The book covers a wide range of recent topics including vortex based control algorithms, incompressible turbulent boundary layers, aerodynamic flow control, control of mixing and reactive flow processes or nonlinear modeling and control of combustion dynamics.
Author: Fenando F. Grinstein Publisher: Cambridge University Press ISBN: 1107137047 Category : Science Languages : en Pages : 481
Book Description
Reviews our current understanding of the subject. For graduate students and researchers in computational fluid dynamics and turbulence.
Author: Publisher: ISBN: Category : Languages : en Pages : 4
Book Description
The proposed theoretical/computational and experimental study addresses the vital two-way coupling between combustion processes and fluid dynamic phenomena associated with schemes for burning liquid fuels in high-speed, accelerating and turning transonic turbulent flows. A major motivation for this type of combustion configuration results from the demonstrated potential for immense improvements in the performance of gas turbine engines via combustion in the turbine passages. This program will address various fundamental issues concerning liquid-fuel combustion in an axially and centrifugally accelerating flow. The major combustion challenge involves ignition and flame-holding of the spray flame in the high-acceleration flow and associated optimization of the injection of the liquid fuel and some secondary air into a protected recirculation zone provided by a cavity.
Author: Gautam Choubey Publisher: Butterworth-Heinemann ISBN: 0323995667 Category : Technology & Engineering Languages : en Pages : 198
Book Description
Scramjet Combustion explores the development of a high-speed scramjet engine operating in the supersonic/hypersonic range for various air and space transport applications. The book explains the basic structure, components, working cycle, and the relevant governing equations in a clear manner that speaks to both advanced and more novice audiences. Particular attention is paid to efficient air–fuel combustion, looking at both the underlying fundamentals of combustion as well strategies for obtaining optimum combustion efficiency. Methods for reaching the chemically correct air–fuel ratio, subsequent flame, and combustion stabilization as air enters at supersonic speed are also outlined. Further, it includes the continuous on-going efforts, innovations, and advances with respect to the design modification of scramjet combustors, as well as different strategies of fuel injections for obtaining augmented performance while highlighting the current and future challenges. Outlines the fundamentals of scramjet engines including their basic structure and components, working cycle, governing equations, and combustion fundamentals affecting the combustion and mixing processes Presents new design modifications of scramjet combustors and different fuel injection strategies including combined fuel injection approaches Discusses core topics such as chemical kinetics in supersonic flow, fuel–air mixing methods, strategies for combating combustion difficulties, and subsequent flame and combustion stabilization that can be applied to scramjets Describes the pedagogy for computational approaches in simulating supersonic flows
Author: Kenneth Kuan-yun Kuo Publisher: John Wiley & Sons ISBN: 111809929X Category : Science Languages : en Pages : 914
Book Description
Detailed coverage of advanced combustion topics from the author of Principles of combustion, Second Edition Turbulence, turbulent combustion, and multiphase reacting flows have become major research topics in recent decades due to their application across diverse fields, including energy, environment, propulsion, transportation, industrial safety, and nanotechnology. Most of the knowledge accumulated from this research has never been published in book form—until now. Fundamentals of Turbulent and Multiphase Combustion presents up-to-date, integrated coverage of the fundamentals of turbulence, combustion, and multiphase phenomena along with useful experimental techniques, including non-intrusive, laser-based measurement techniques, providing a firm background in both contemporary and classical approaches. Beginning with two full chapters on laminar premixed and non-premixed flames, this book takes a multiphase approach, beginning with more common topics and moving on to higher-level applications. In addition, Fundamentals of Turbulent and Multiphase Combustion: Addresses seven basic topical areas in combustion and multiphase flows, including laminar premixed and non-premixed flames, theory of turbulence, turbulent premixed and non-premixed flames, and multiphase flows Covers spray atomization and combustion, solid-propellant combustion, homogeneous propellants, nitramines, reacting boundary-layer flows, single energetic particle combustion, and granular bed combustion Provides experimental setups and results whenever appropriate Supported with a large number of examples and problems as well as a solutions manual, Fundamentals of Turbulent and Multiphase Combustion is an important resource for professional engineers and researchers as well as graduate students in mechanical, chemical, and aerospace engineering.
Author: Srivatsava Venkataranga Puranam
Author: Srivatsava Venkataranga Puranam
Author: Ben James Colcord
Author: 
Author: Petros Koumoutsakos
Author: Fenando F. Grinstein
Author: 
Author: Gautam Choubey
Author: Ralph D. Cooper
Author: Kenneth Kuan-yun Kuo
Author: J. L. Dussourd