Download or read book A Premixed Laminar Flame Interacting with a Vortex Resulting in Flame Stretch and Quenching written by William Lafayette Roberts IV. and published by . This book was released on 1992 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stretch Induced Quenching in Flame Vortex Interactions written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2019-01-04 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: The flame-vortex interaction problem is a natural configuration in which several issues relevant to turbulent combustion can be addressed: effect of strain-rate and curvature, effect of the Lewis number, effect of heat losses, effect of complex chemistry, and flame-generated turbulence. In such an approach, the interaction of an isolated vortex with a laminar premixed flame is viewed as a unit process of a turbulent premixed flame in which the reaction zone keeps a laminar like structure locally; this is precisely the case of the wrinkled flame or flamelet regime in turbulent combustion. The present work complements previous studies and involves the study of the interaction of a vortex pair and a laminar premixed flame in a planar two-dimensional geometry, together with numerical simulations. This geometry is quite unique since most studies have considered axisymmetric vortex rings. Such a geometry offers several advantages over previous studies. Samaniego, J.-M. ...
Download or read book Experimental Quantification of Transient Stretch Effects from Vortices Interacting with Premixed Flames written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The understanding of complex premixed combustion reactions is paramount to the development of new concepts and devices used to increase the overall usefulness and capabilities of current technology. The evolution from laminar spherically propagating flames to turbulent chemistry is a logical and necessary process to study the complex interactions which occur within any modern practical combustion device. Methane-air flames were chosen to observe the mild affects of thermo-diffusive stability. Five primary propane equivalence ratios were utilized for investigation: 0.69, 0.87, 1.08, 1.32, and 1.49. The choice of equivalence ratio was strategically made so that the 0.69/1.49 and 0.87/1.32 mixtures have the same undiluted flame propagation rate, dr/dt. Therefore, in the undiluted case, there are two flame speeds represented by these mixtures. Three vortices were selected to be used in this investigation. The vortex rotational velocities were measured to be 77 cm/s, 266 cm/s and 398 cm/s for the “weakâ€, “medium†and “strong†vortices, respectively. Ignition of the flame occurred in two ways: (1) spark-ignition or (2) laser ignition using an Nd:YAG laser at its second harmonic in order to quantify the effect of electrode interference. Accompanying high-speed chemiluminescence imaging measurements, instantaneous pressure measurements were obtained to give a more detailed understanding of the effect of vortex strength on reactant consumption rate over an extended time scale and to explore the use of a simple measurement to describe turbulent mixing. Further local flame-vortex interface analysis was conducted using non-invasive laser diagnostics, such as particle image velocimetry and planer laser induced fluorescence of the OH radical. The dependence of heat release rate on temperature provides an estimation of the strain rate dependence of the reaction rate.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Investigation of the Interaction Between a K rm n Vortex Street and a Premixed Laminar Flame written by Izak Namer and published by . This book was released on 1980 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: The interaction of a premixed C2H4-air flame with a Karman vortex street was studied. Laser Doppler anemometry was used for velocity measurements and Rayleigh scattering was used to measure total gas density. A reference hotwire was used to enable phase-locked ensemble averaging to be performed on the data. The velocity measurements, for vortex shedding cylinder Reynolds numbers 73 and 110, indicated that the vortex street and, hence, the flow field upstream of the flame is deflected by the flame. This is due to the pressure drop across the flame which is necessary to accelerate the flow behind the flame. The vortices were not observed behind the flame. The combination of dilatation and increased dissipation 'consumed' the vortices. Density statistics obtained from Rayleigh scattering measurements were compared with predictions by the Bray-Moss-Libby (B-M-L) model which neglects intermediate states. Density fluctuations were overpredicted by the B-M-L model by a small amount for 73 and 110. The flame was essentially a wrinkled-laminar flame for these conditions. However, for (UD/v) = 500 the flame consisted of a distributed reaction zone and intermediate states accounted for as much as 80% of all states encountered in portions of the flame. The B-M-L model significantly overpredicted density fluctuation statistics for this condition. A qualitative comparison was made with numerical calculations by Karasalo and Namer for the time dependent interaction of a flame with an ideal Karman vortex street and suggestions for improving the model were made.
Download or read book Measurements of Flame vortex Interaction Dynamics and Chemistry written by Charles Jeffrey Mueller and published by . This book was released on 1996 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Interaction Between a Laminar Flame and Its Self generated Flow written by Derek Dunn-Rankin and published by . This book was released on 1985 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interaction of a Vortex and a Premixed Flame written by Christopher J. Rutland and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Theoretical and Experimental Study of Preferential diffusion stretch Interactions of Laminar Premixed Flames written by Oh Chae Kwon and published by . This book was released on 2000 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Flame Turbulence Interactions written by and published by . This book was released on 1993 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: The interaction between individual vortices and a premixed laminar flame was investigated in order to characterize the underlying dynamics of flame-turbulence interactions and thereby gain an improved understanding of premixed turbulent flames. In addition, previous two-dimensional flame structure measurements made in turbulent premixed flames were re-analyzed in order to obtain flame curvature and orientation statistics ... Premixed Turbulent Flames, Flame-Vortex Interactions, Turbulence-Flame Interactions, Turbulent Flame Structure.
Download or read book Vortex flame Interactions in Opposing jet Premixed Flames written by V. R. Katta and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fundamentals of Premixed Turbulent Combustion written by Andrei Lipatnikov and published by CRC Press. This book was released on 2012-10-24 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lean 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
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1993 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Strain Vorticity and Turbulence on Premixed Flames written by Christopher J. Rutland and published by . This book was released on 1989 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: The laminar flame problem is solved using a phase plane method.
Download or read book Experimental and Numerical Study of Dynamics of Premixed Hydrogen Air Flames Propagating in Ducts written by Huahua Xiao and published by Springer. This book was released on 2015-11-03 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis offers important new insights into and a deeper understanding of premixed flame instabilities and hydrogen safety. Further, it explains the underlying mechanisms that control the combustion processes in tubes. The author’s previous scientific accomplishments, which include a series of high-quality publications in the best journals in our field, Combustion and Flame and International Journal of Heat and Mass Transfer, are very impressive and have already made a significant contribution to combustion science.
Download or read book Annual Reviews of Computational Physics V written by Dietrich Stauffer and published by World Scientific. This book was released on 1997 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this fifth volume of the authoritative series, the simulation of forest fires, flames, and hydrodynamics is presented in the first three articles. The next two deal with quantum simulations, in particular for two dimensions (quantum Hall effect and monolayers). Biology is connected with the last two articles: we learn from biological evolution to complement computer hardware and software with evolware, or we simulate immunology.
