Experimental Investigation of the Dynamics and Structure of Lean-premixed Turbulent Combustion
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Published: 2003
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Published: 2003
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Author: Nedunchezhian Swaminathan
Publisher: Cambridge University Press
Published: 2011-04-25
Total Pages: 447
ISBN-13: 1139498584
DOWNLOAD EBOOKA work on turbulent premixed combustion is important because of increased concern about the environmental impact of combustion and the search for new combustion concepts and technologies. An improved understanding of lean fuel turbulent premixed flames must play a central role in the fundamental science of these new concepts. Lean premixed flames have the potential to offer ultra-low emission levels, but they are notoriously susceptible to combustion oscillations. Thus, sophisticated control measures are inevitably required. The editors' intent is to set out the modeling aspects in the field of turbulent premixed combustion. Good progress has been made on this topic, and this cohesive volume contains contributions from international experts on various subtopics of the lean premixed flame problem.
Author: Basant Singh Sikarwar
Publisher: Springer Nature
Published: 2021-04-21
Total Pages: 891
ISBN-13: 9811601593
DOWNLOAD EBOOKThis book comprises the select proceedings of the International Conference on Future Learning Aspects of Mechanical Engineering (FLAME 2020). This volume focuses on current research in fluid and thermal engineering and covers topics such as heat transfer enhancement and heat transfer equipment, heat transfer in nuclear applications, microscale and nanoscale transport, multiphase transport and phase change, multi-mode heat transfer, numerical methods in fluid mechanics and heat transfer, refrigeration and air conditioning, thermodynamics, space heat transfer, transport phenomena in porous media, turbulent transport, theoretical and experimental fluid dynamics, flow measurement techniques and instrumentation, computational fluid dynamics, fluid machinery, turbo machinery and fluid power. Given the scope of its contents, this book will be interesting for students, researchers as well as industry professionals.
Author: Frank Tat Cheong Yuen
Publisher:
Published: 2009
Total Pages: 306
ISBN-13: 9780494608951
DOWNLOAD EBOOKTurbulent premixed propane/air and methane/air flames were studied using planar Rayleigh scattering and particle image velocimetry on a stabilized Bunsen type burner. The fuel-air equivalence ratio was varied from &phis; = 0:7 to 1.0 for propane flames, and from &phis; = 0:6 to 1.0 for methane flames. The non-dimensional turbulence intensity, u'/ SL (ratio of fluctuation velocity to laminar burning velocity), covered the range from 3 to 24, equivalent to conditions of corrugated flamelets and thin reaction zones regimes. Temperature gradients decreased with the increasing u'/SL and levelled off beyond u'/SL > 10 for both propane and methane flames. Flame front thickness increased slightly as u'/SL increased for both mixtures, although the thickness increase was more noticeable for propane flames, which meant the thermal flame front structure was being thickened. A zone of higher temperature was observed on the average temperature profile in the preheat zone of the flame front as well as some instantaneous temperature profiles at the highest u'/SL. Curvature probability density functions were similar to the Gaussian distribution at all u'/ SL for both mixtures and for all the flame sections. The mean curvature values decreased as a function of u'/ SL and approached zero. Flame front thickness was smaller when evaluated at flame front locations with zero curvature than that with curvature. Temperature gradients and FSD were larger when the flame curvature was zero. The combined thickness and FSD data suggest that the curvature effect is more dominant than that of the stretch by turbulent eddies during flame propagation. Integrated flame surface density for both propane and methane flames exhibited no dependance on u'/S L regardless of the FSD method used for evaluation. This observation implies that flame surface area may not be the dominant factor in increasing the turbulent burning velocity and the flamelet assumption may not be valid under the conditions studied. Dkappa term, the product of diffusivity evaluated at conditions studied and the flame front curvature, was a magnitude smaller than or the same magnitude as the laminar burning velocity.
Author: Norbert Peters
Publisher: Cambridge University Press
Published: 2000-08-15
Total Pages: 322
ISBN-13: 1139428063
DOWNLOAD EBOOKThe 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.
Author: Anna Schwarz
Publisher: Springer Science & Business Media
Published: 2009-06-17
Total Pages: 304
ISBN-13: 3642020380
DOWNLOAD EBOOKNovember, 2008 Anna Schwarz, Johannes Janicka In the last thirty years noise emission has developed into a topic of increasing importance to society and economy. In ?elds such as air, road and rail traf?c, the control of noise emissions and development of associated noise-reduction techno- gies is a central requirement for social acceptance and economical competitiveness. The noise emission of combustion systems is a major part of the task of noise - duction. The following aspects motivate research: • Modern combustion chambers in technical combustion systems with low pol- tion exhausts are 5 - 8 dB louder compared to their predecessors. In the ope- tional state the noise pressure levels achieved can even be 10-15 dB louder. • High capacity torches in the chemical industry are usually placed at ground level because of the reasons of noise emissions instead of being placed at a height suitable for safety and security. • For airplanes the combustion emissions become a more and more important topic. The combustion instability and noise issues are one major obstacle for the introduction of green technologies as lean fuel combustion and premixed burners in aero-engines. The direct and indirect contribution of combustion noise to the overall core noise is still under discussion. However, it is clear that the core noise besides the fan tone will become an important noise source in future aero-engine designs. To further reduce the jet noise, geared ultra high bypass ratio fans are driven by only a few highly loaded turbine stages.
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Published: 1999
Total Pages: 974
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DOWNLOAD EBOOKAuthor: N. Swaminathan
Publisher: Cambridge University Press
Published: 2022-01-06
Total Pages:
ISBN-13: 1108572758
DOWNLOAD EBOOKExplore a thorough and up to date overview of the current knowledge, developments and outstanding challenges in turbulent combustion and application. The balance among various renewable and combustion technologies are surveyed, and numerical and experimental tools are discussed along with recent advances. Covers combustion of gaseous, liquid and solid fuels and subsonic and supersonic flows. This detailed insight into the turbulence-combustion coupling with turbulence and other physical aspects, shared by a number of the world leading experts in the field, makes this an excellent reference for graduate students, researchers and practitioners in the field.
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Published: 1995
Total Pages: 692
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DOWNLOAD EBOOKAuthor: Andrei Lipatnikov
Publisher: CRC Press
Published: 2012-10-24
Total Pages: 548
ISBN-13: 1466510250
DOWNLOAD EBOOKLean burning of premixed gases is considered to be a promising combustion technology for future clean and highly efficient gas turbine combustors. Yet researchers face several challenges in dealing with premixed turbulent combustion, from its nonlinear multiscale nature and the impact of local phenomena to the multitude of competing models. Filling