Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Experimental Study Of Flame Blowout And Flashback In A System Involving Fuel Jet Within Homogeneous Turbulent Streams Of Air And Fuel
Download Experimental Study Of Flame Blowout And Flashback In A System Involving Fuel Jet Within Homogeneous Turbulent Streams Of Air And Fuel full books in PDF, epub, and Kindle. Read online Experimental Study Of Flame Blowout And Flashback In A System Involving Fuel Jet Within Homogeneous Turbulent Streams Of Air And Fuel ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Experimental Study of Flame-blowout and Flashback in a System Involving Fuel Jet Within Homogeneous Turbulent Streams of Air and Fuel by : Krishnendu Kar
Download or read book Experimental Study of Flame-blowout and Flashback in a System Involving Fuel Jet Within Homogeneous Turbulent Streams of Air and Fuel written by Krishnendu Kar and published by . This book was released on 1990 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Masters Theses in the Pure and Applied Sciences by : Wade H. Shafer
Download or read book Masters Theses in the Pure and Applied Sciences written by Wade H. Shafer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) * at Purdue University in 1 957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all con cerned if the printing and distribution of the volumes were handled by an interna tional publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Cor poration of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 36 (thesis year 1991) a total of 11,024 thesis titles from 23 Canadian and 161 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this important annual reference work. While Volume 36 reports theses submitted in 1991, on occasion, certain univer sities do report theses submitted in previous years but not reported at the time.
Book Synopsis Masters Theses in the Pure and Applied Sciences by : W. H. Shafer
Download or read book Masters Theses in the Pure and Applied Sciences written by W. H. Shafer and published by Springer Science & Business Media. This book was released on 1993 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 36 reports (for thesis year 1991) a total of 11,024 thesis titles from 23 Canadian and 161 US universities. The organization of the volume, as in past years, consists of thesis titles arranged by discipline, and by university within each discipline. The titles are contributed by any and all a
Book Synopsis Turbulent Premixed Flames by : Nedunchezhian Swaminathan
Download or read book Turbulent Premixed Flames written by Nedunchezhian Swaminathan and published by Cambridge University Press. This book was released on 2011-04-25 with total page 447 pages. Available in PDF, EPUB and Kindle. Book excerpt: A 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.
Book Synopsis Masters Abstracts International by :
Download or read book Masters Abstracts International written by and published by . This book was released on 1994 with total page 832 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1987 with total page 934 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Experimental Study of Turbulent Jet and Lifted Jet Flame Unsteadiness from a Non-linear Dynamics Perspective by : Sina Rafati
Download or read book Experimental Study of Turbulent Jet and Lifted Jet Flame Unsteadiness from a Non-linear Dynamics Perspective written by Sina Rafati and published by . This book was released on 2021 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research aims to investigate the nonlinear dynamics of the non-reacting jets and non-premixed lifted jet flames. The goal is to understand better how the flow system dynamics change over time and identify the path toward unwanted conditions such as flashback, extinction, or blowout to limit combustors' dynamical failure. The existence of these undesirable conditions is bound to the fluid's history, meaning that initiated perturbation may persist in the system for time scales comparable to large-scale flow timescales. Hence, the notion is to utilize jet and jet flames as a study test case to work out how the flow evolves dynamically with the hope of understanding how to limit occurrences of the chaotic unwanted condition. Initially, planar particle image velocimetry has been used for the development of the methodologies. I have used planar data to investigate the nonlinear dynamics of non-reacting turbulent jets, with a low-to-moderate Reynolds number using the single-trajectory framework and ensemble framework. I have used Lyapunov exponents to calculate the spectra of scaling indices of the attractor. Then, I used Lagrangian Coherent Structures (LCSs), which are defined as manifolds that are locally Euclidean and invariant, to study the relationship between Lyapunov exponent changes with flow topological features. These LCSs behave as hypersurfaces with maximally repelling or attracting properties. These various methodologies were used to investigate flame-turbulence interaction in lifted jet flames. The Lagrangian framework is shown to be effective at revealing the kinematics associated with flame-turbulence interaction. The LCSs' time history represents how eddy structures interact with the flame and highlight their role in the dynamics of the lifted jet flames. Finally, I have investigated the flame and turbulence interaction using high-speed luminosity imaging and simultaneous three-dimensional particle image velocimetry. The three-dimensional Lagrangian structures provide us a more detailed flow-flame interaction. It is shown that the flow features associated with attracting LCSs can create a barrier attracting the flame that makes the flame move upstream. In contrast, the presence of repelling LCSs near stationary flames breaks the balance between the gas velocity and flame propagation speed, causing the flame to become non-stationary and move downstream. It was also found that the repelling LCSs induce negative curvature on the flame surface whereas pushing the flame toward the products. However, the attracting LCSs induce positive curvature on the flame surface and draws the flame toward the reactants
Book Synopsis Flashback Propensity of Premixed Jet Flames Operated on Synthetic Gaseous Fuel with Alternative Burner Configurations and Materials by : Zhixuan Duan
Download or read book Flashback Propensity of Premixed Jet Flames Operated on Synthetic Gaseous Fuel with Alternative Burner Configurations and Materials written by Zhixuan Duan and published by . This book was released on 2013 with total page 195 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrogen enriched fuel generated from a variety of resources such as coal and biomass gasification provides an extra option for lean premixed combustion systems. Flashback is the main operability issue associated with this application. In the present work, boundary layer flashback in a jet flame configuration is investigated. Previous research is extended to more practical conditions where turbulent flows with alternative fuels are prevalent. The importance of burner rim conditions, recently revealed, is investigated systematically in the current work. To fulfill the research goals, a jet burner with interchangeable configuration and materials was built. An inline heater provided preheated air up to 810 K. Systematic studies addressing the quantitative influence of various parameters such as fuel compositions, inlet temperature, burner tip temperature, burner material, enclosure size, and burner diameter on flashback propensity were conducted. A comprehensive overview of the flashback limits for all conditions tested in the current study as well as those published previously is presented. The collective results indicate that the burner materials, tip temperature and flame confinement play significant roles for flashback propensity. A statistics based model demonstrated that better correlations arise when the tip temperature is introduced as an input, whereas a physical model revealed that the critical velocity gradient when flashback occurs is proportional to the laminar flame speed computed based on the tip temperature. The addition of multiple parameters further refined the prediction of the flashback propensity. The present work used a heat transfer analysis to show that the upstream flame propagation during flashback is affected by the burner material. The material with lower thermal conductivity yields larger flashback propensity but slower flame regression inside the tube. These observations can be potentially exploited to minimize the negative impacts of flashback in practical applications. A heat transfer model, developed to estimate burner tip temperature, was successful in demonstrating the potential of advanced heat transfer modeling in predicting flashback propensity of alternative fuels with a given burner configuration.
Book Synopsis Effects of Leading-Edge Flame Behavior on Flame Stabilization and Blowout by :
Download or read book Effects of Leading-Edge Flame Behavior on Flame Stabilization and Blowout written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this work was to identify the mechanisms that effect stabilization of hydrocarbon jet flames. Methane, nitrogen, and co-flowing air were regulated and directed through a burner that created fully-developed fuel flow with concurrent air. The behavior of the reaction zone at the leading-edge was analyzed from digital images obtained from a camera optimally positioned to capture the movements of the entire flame front. Low Reynolds number flows allowed for the investigation of hysteretic behavior. The hysteresis regime refers to the situation where the jet flame has dual positions favorable to flame stabilization: attached and lifted. Results indicate that flame height in hysteresis is significantly impacted by high velocities of co-flow and that past a critical value a local minimum will be created. Fully turbulent lifted flames were also studied to determine the fluctuations in the height of lifted methane flames in the presence of air co-flow. The partially-premixed flame front of the lifted flame fluctuates in the axial direction, with the fluctuations becoming greater in flames stabilized further downstream. These fluctuations are also observed in flames where blowout is imminent. The height and rate of these fluctuations are studied with respect to average height, flow velocities, and Reynolds number. Additionally, the mechanisms that cause jet-flame blowout, particularly in the presence of air co-flow, are not completely understood. Two types of experiments are described, and the data report that a predictor of blowout is the prior disappearance of the axially-oriented flame branch which is consistently witnessed despite a turbulent flameÃØâ'Ơâ"Øs inherent variable behavior. The conclusions are supported by experiments with nitrogen-diluted flames. A blowout parameter is also calculated for methane flames in co-flow and diluted methane flames that can be used to predict at what flow velocities blowout will occur. This work analyzes flames near the bu.
Book Synopsis Flashback Mechanisms in Lean Premixed Gas Turbine Combustion by : Ali Cemal Benim
Download or read book Flashback Mechanisms in Lean Premixed Gas Turbine Combustion written by Ali Cemal Benim and published by Academic Press. This book was released on 2014-12-01 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: Blending fuels with hydrogen offers the potential to reduce NOx and CO2 emissions in gas turbines, but doing so introduces potential new problems such as flashback. Flashback can lead to thermal overload and destruction of hardware in the turbine engine, with potentially expensive consequences. The little research on flashback that is available is fragmented. Flashback Mechanisms in Lean Premixed Gas Turbine Combustion by Ali Cemal Benim will address not only the overall issue of the flashback phenomenon, but also the issue of fragmented and incomplete research. Presents a coherent review of flame flashback (a classic problem in premixed combustion) and its connection with the growing trend of popularity of more-efficient hydrogen-blend fuels Begins with a brief review of industrial gas turbine combustion technology Covers current environmental and economic motivations for replacing natural gas with hydrogen-blend fuels
Book Synopsis Studies in Flame Propagation and Blowout by :
Download or read book Studies in Flame Propagation and Blowout written by and published by . This book was released on 2006 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report outlines our most recent research work on the topic of upstream flame propagation and blowout in hydrocarbon jet flames. Outlined specifically are the recent elements of the research for the study of fundamental structural characteristics of jet flames and related flame/spray/flow interactions. Specifically, the scope encompasses further optical imaging investigations of flame structure and behavior, and an exploratory study of the effects of co-flow air on extinction and blowout. Analysis of the results of experiments to understand the behavior of gaseous and spray flame counterparts is the main deliverable. The methodology of the research is largely experimental, emphasizing the application of optical diagnostic techniques to instantaneously visualize reaction zones. The main efforts to report since the last update are the following: 1) Studies have been launched that examine the development of combustion in an initially non-reacting methane jet after ignition at a downstream location and 2) The driving mechanisms that cause jet-flame blowout, particularly in the presence of air co-flow, have been investigated. This work attempts to determine the role of fuel velocity and air co-flow in the blowout phenomenon.
Book Synopsis Theories of Turbulent Combustion in High Speed Flows by : Paul A. Libby
Download or read book Theories of Turbulent Combustion in High Speed Flows written by Paul A. Libby and published by . This book was released on 1991 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Flashback Characteristics of Syngas-Type Fuels Under Steady and Pulsating Conditions by :
Download or read book Flashback Characteristics of Syngas-Type Fuels Under Steady and Pulsating Conditions written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this project was to improve understanding and modeling of flashback, a significant issue in low emissions combustors containing high levels of hydrogen. Experimental studies were performed over a range of fuel compositions, flow velocities, reactant temperatures, and combustor pressures to study the factors leading to flashback. In addition, high speed imaging of the flashback phenomenon was obtained. One of the key conclusions of this study was that there existed multiple mechanisms which lead to flashback, each with different underlying parametric dependencies. Specifically, two mechanisms of 'flashback' were noted: rapid flashback into the premixer, presumably through the boundary layer, and movement of the static flame position upstream along the centerbody. The former and latter mechanisms were observed at high and low hydrogen concentrations. In the latter mechanism, flame temperature ratio, not flame speed, appeared to be the key parameter describing flashback tendencies. We suggested that this was due to an alteration of the vortex breakdown location by the adverse pressure gradient upstream of the flame, similar to the mechanism proposed by Sattelmayer and co-workers [1]. As such, a key conclusion here was that classical flashback scalings derived from, e.g., Bunsen flames, were not relevant for some parameter regimes found in swirling flames. In addition, it was found that in certain situations, pure H2 flames could not be stabilized, i.e., the flame would either flashback or blowout at ignition. This result could have significant implications on the development of future high hydrogen turbine systems.
Book Synopsis Experimental Investigation on the Effects of Free Stream Turbulence and Fuel Type on Structure and Blowoff Characteristics of Turbulent Premixed Bluff-body Stabilized Flames by : Bikram Roy Chowdhury
Download or read book Experimental Investigation on the Effects of Free Stream Turbulence and Fuel Type on Structure and Blowoff Characteristics of Turbulent Premixed Bluff-body Stabilized Flames written by Bikram Roy Chowdhury and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation on the effect of different levels of turbulence intensity and properties of the fuel/air mixture on the structure and characteristics of lean flames stabilized on an axisymmetric bluff body is described in this thesis. Simultaneous imaging of hydroxyl (OH) and formaldehyde (CH2O) by planar laser induced fluorescence and particle image velocimetry (PIV) were used to study the interaction between the flame and the flow field. CH2O fluorescence and the pixel-by-pixel multiplication of OH and CH2O fluorescence signals were utilized to mark preheat and heat release regions respectively. In addition, high-speed chemiluminescence imaging was performed to understand the time resolved characteristics of the flame. The first part of the thesis focuses on the characteristics of stably burning lean methane/-, propane/- and ethylene/air flames when subjected to low (4 %), moderate (14 %) and intense (24 and 30%) levels of free stream turbulence. The flame front structure was observed to be strongly dependent on the free stream turbulence level of the incoming fuel/air mixture as well on the properties of the fuel/air mixture. Formation of cusps and unburnt mixture fingers were observed as the turbulence intensity was increased from 4 to 14 % but, the heat release region remained continuous. Under intense turbulence conditions, methane/- and ethylene/air (f = 0.85) flames exhibited localized extinctions along the flame sheet and flamelet merging events which created isolated pockets of reactants in the flame envelope. In addition to these features, propane/- and ethylene/air (f=0.655) flames exhibited the occurrence of flame fragmentation events and the general shape of these flames were observed to intermittently switch from a symmetric (varicose) to asymmetric (sinuous) mode. Several properties were measured to characterize the effects of turbulence – flame interaction which includes the average preheat and reaction zone thicknesses, strain rates and curvature along the flame front, burning fraction, flame brush thickness, flame surface density, area ratio and turbulent flame speed. The next part of the thesis focuses on blowoff dynamics of lean methane/-, propane/- and ethylene/air flames for mean velocities of 5, 10 and 15 m/s and subjected to free stream turbulence levels from 4 to 30%. Apart from the propane/air flames at an apporach velcoity of 5 m/s and turbulence intensity of 30 %, increasing turbulence intensity was found to reduce the flame stability. The blowoff equivalence ratios of propane/air flames was observed to be higher than methane/- and ethylene/air flames. As blowoff was approached, the flame front and shear layer vortices entangled inducing high local strain rates on the flame front that exceed the extinction strain rate resulting in significant breaks along the reaction zone. At conditions near blowoff, significant increase in the frequency of breaks along the reaction zone was observed for low and moderate turbulence conditions. For the higher turbulence conditions, fragmentation of the flame along with the presence of sinuous wakes was observed which aided in the penetration of reactants into the recirculation zone. Velocity vectors near the flame holes indicate the penetration of the reactants into the recirculation zone. Mostly similar sequence of events was observed for methane/-, propane/- and ethylene/air flames near blowoff. Several properties weremeasured to characterize the near blowoff flames which include the strain rate and curvature statistics along the flame front, burning fraction, asymmetric index and the average duration of the blowoff event. Based on the observation from the experiments, turbulent flame speed was attributed to be the primary factor in governing the blowoff equivalence ratio. This point of view was examined by comparing the mean strain rate of methane/- and ethylene/air flames at the equivalence ratio corresponding to near blowoff for propane/air flames.
Book Synopsis Flame-flow Interaction During Premixed and Stratified Swirl Flame Flashback in an Annular Swirl Combustor by : Rakesh Ranjan (Ph. D.)
Download or read book Flame-flow Interaction During Premixed and Stratified Swirl Flame Flashback in an Annular Swirl Combustor written by Rakesh Ranjan (Ph. D.) and published by . This book was released on 2018 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: The interaction between a propagating flame and the approach flow is critical to the understanding of boundary layer flashback of swirling flames. In this work, I investigated this interaction during flashback using high-speed luminosity imaging and simultaneous three-dimensional particle image velocimetry. The mean axial velocity through the mixing tube is kept at 2.5 m/s while the hydrogen enrichment of the fuel is varied up to 87%. These flashback experiments are conducted at pressures ranging from 1 to 5 atm. To understand the flame-flow interaction physics, I developed a novel analysis methodology for low-turbulence fully-premixed methane-air swirl flame flashback, by stacking the planar flame profiles and three-dimensional velocity data. In the quasi-reconstructed velocity field, the motion of an approaching fluid parcel is analyzed in the frame-of-reference of the propagating flame. For the first time, the role of inertial forces in swirling flame-flow interaction is revealed. Subsequently, I investigated the effect of fuel-air partial premixing on the flashback behavior at atmospheric and elevated pressures. A swirler-based fuel-injection system was used to create fuel-air stratification in the radial direction. For elevated pressure measurements, an optically accessible elevated pressure chamber was designed and constructed to conduct flashback experiments up to 5 atm. The spatial distribution of the equivalence ratio under non-reacting conditions was investigated using planar laser-induced fluorescence with acetone as the fuel tracer. It was observed that fuel-air pockets were distributed across the mixing tube width, although in an average sense, the fuel-air mixture was radially stratified. The global behavior of upstream flame propagation is reported for different levels of hydrogen-enrichment. For stratified hydrogen-rich flashback, the propagation path of the flame changes from the inner wall to outer wall induced by the faster chemistry of stoichiometric mixtures that are frequently present near the outer wall. This behavior of hydrogen-rich flashback persists even at elevated pressures up to 5 atm, although the propagation of the flame occurs as a wide flame tongue as opposed to the acute-tipped flame structures present in the atmospheric cases
Book Synopsis Fundamentals of Combustion Processes by : Sara McAllister
Download or read book Fundamentals of Combustion Processes written by Sara McAllister and published by Springer Science & Business Media. This book was released on 2011-05-10 with total page 315 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamentals of Combustion Processes is designed as a textbook for an upper-division undergraduate and graduate level combustion course in mechanical engineering. The authors focus on the fundamental theory of combustion and provide a simplified discussion of basic combustion parameters and processes such as thermodynamics, chemical kinetics, ignition, diffusion and pre-mixed flames. The text includes exploration of applications, example exercises, suggested homework problems and videos of laboratory demonstrations
Book Synopsis Gas Turbine Combustion by : Arthur H. Lefebvre
Download or read book Gas Turbine Combustion written by Arthur H. Lefebvre and published by CRC Press. This book was released on 2010-04-26 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflecting the developments in gas turbine combustion technology that have occurred in the last decade, Gas Turbine Combustion: Alternative Fuels and Emissions, Third Edition provides an up-to-date design manual and research reference on the design, manufacture, and operation of gas turbine combustors in applications ranging from aeronautical to po
