3 edition of Role of acoustics in flame/vortex interactions found in the catalog.
Role of acoustics in flame/vortex interactions
by National Aeronautics and Space Administration, Langley Research Center, National Technical Information Service, distributor in Hampton, Va, [Springfield, Va
Written in English
|Statement||T.L. Jackson, Michele G. Macaraeg, M.Y. Hussaini.|
|Series||NASA contractor report -- 191429., ICASE report -- no. 93-4., NASA contractor report -- NASA CR-191429., ICASE report -- no. 93-4.|
|Contributions||Macaraeg, Michele G., Hussaini, M. Yousuff., Langley Research Center.|
|The Physical Object|
Non-normality and internal flame dynamics in premixed flame–acoustic interaction - Volume - PRIYA SUBRAMANIAN, R. I. SUJITH. Flame-vortex interactions are among the most signi cant instability mechanisms in large- Altay et al.,), where the authors emphasize the role of vortex kinematics (formation, separation and convection) and its interactions with acoustics and the ame in driving the observed instabilities. This paper presents an experimental investigation.
The following paper deals with acoustic flame suppression mechanics in a microgravity environment with measurements taken from an Arduino-based sensor system and validation of the technique. A Zippo lighter is ignited in microgravity and then displaced from the base of the flame and suppressed using surface interactions with single tone acoustic waves to extinguished the flame. In this analysis, the interaction of the flame with the flow environment is modeled as a perfectly-mixed chemical reactor. With this model, the governing parameter is the ratio between a flow time-scale (or residence time in the reactor) and a chemical-time scale, and the key observable is the reactor's maximum temperature.
In this paper the Triple Annular Research Swirler, a fuel injector characterized by complex design with three concentric air passages, has been studied numerically. A swirl-stabilized lean premixed flame has been simulated by means of Large Eddy Simulation. The computations characterize successfully the dynamics of the flame and their interactions with the complex swirling flow. Firstly, the stability of the vortex compound was evaluated. Most often, it remains compact, but when unstable, it can break as vertically coupled vortex dipoles (called hetons). Secondly, we studied the interaction between a vertically tilted cyclone and lenses. Then, the lenses first undergo anticlockwise rotation determined by the surface.
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The role of acoustics in flame/vortex interactions is examined via asymptotic analysis and numerical simulation. The model consists of a one-step, irreversible Arrhenius reaction between initially. Get this from a library.
Role of acoustics in flame/vortex interactions. [T L Jackson; Michele G Macaraeg; M Yousuff Hussaini; Langley Research Center.].
Abstract. The role of acoustics in flame/vortex interactions is examined via asymptotic analysis and numerical simulation. The model consists of a one-step, irreversible Arrhenius reaction between initially unmixed species occupying adjacent half-planes which are allowed to mix and react by convection and diffusion in the presence of an acoustic field or a time-varying pressure field of small.
Shepherd and Lee ()], etc. Oran and Gardner () provide a fine review of combustion-acoustics interactions with an emphasis on the physics rather than the mathematical analysis and techniques. In the present study, the role of acoustics in the flame/vortex interaction process is investigated.
Vortex interactions with flames play a key role in many practical combustion applications. Such interactions drive a large class of combustion instabilities, they control to a great extent the structure of turbulent flames and the corresponding rates of reaction, they occur under transient operations or when flames travel in ducts containing by: PIV Characterization of Flame-Acoustics Interaction.
P AGLIAR Book. Full-text available From the data collected on the combustor the processes of vortex shedding, growth, interactions and. Role of Coherent Structures in Turbulent Premixed Flame Acoustics. “ Flame Interactions as a Source of Noise and Combustion Instabilities,” 10th AIAA/CEAS Maurel S., Borée J.
and Lumley J. L., “ Extended Proper Orthogonal Decomposition: Application to Jet/Vortex Interaction,” Flow, Turbulence and Combustion, Vol. 67, No. The complicated flame–vortex interaction dynamics can be reduced to a single parameter, S c (ρ u / ρ b − 1), which carries information about the interaction between the flame and the hydrodynamics with different reactant mixture compositions and the volume expansion as a result of the chemical reaction.
Direct numerical simulations of flame kernel-vortex interactions are implemented in an axisymmetric configuration using a two-step global mechanism to study the different combustion regimes of the interactions.
Four combustion regimes have been identified. They include: (1) the “laminar kernel” regime, (2) the “wrinkled kernel” regime, (3) the “breakthrough” regime, and (4) the. Among the literature on acoustics the book of Pierce  is an excellent introduction available for a low price from the Acoustical Society of America.
In the preparation of the lecture notes we consulted various books which cover different aspects of the problem [14, 16, 18, 37, 48, 70, 87, 93, 99,]. This vortex core has a conical helical shape that interacts—as it winds out—with the ISL and the flame stabilized along it. The simulated helical vortex core (HVC) exists in both reacting and non-reacting flows; in the latter, it is dominated by the off-axis motion, whereas in the reacting case, that motion is damped and only remains the.
Thermoacoustics is the interaction between temperature, density and pressure variations of acoustic waves. Thermoacoustic heat engines can readily be driven using solar energy or waste heat and they can be controlled using proportional can use heat available at low temperatures which makes it ideal for heat recovery and low power applications.
American Institute of Aeronautics and Astronautics Sunrise Valley Drive, Suite Reston, VA Both the chapters involve coupling of topics like flame stretch and flame vortex interactions. The concept of flame stretch, however, is dealt with in greater detail in Chapter – 9, where the impact of combustion dynamics on the internal structure of flames is discussed.
As in the first part of the book, here, also, the “asides” help to. Analysis of the Interactions of the Precessing Vortex Core with a Spray Flame in a Swirl Burner. Authors; A review of oscillation mechanisms and the role of the precessing vortex core (PVC) in swirl combustion systems, Prog.v Energy.
Guedot L., Lartigue G., Moureau V. () Analysis of the Interactions of the Precessing Vortex Core. The escalating flame-sound interaction occurs in tandem with other physical mechanisms, leading to a complex web of interactions, most of which are nonlinear.
They include flame-vortex interactions, flame response to fluctuations in fuel concentration, entropy waves, flame-structure interactions. Equation of Linear Acoustics 4 5 Vortex Sound The Role of Vorticity in Lighthill’s Theory Blade–Vortex Interactions in Three Dimensions Sound Produced by Vortex Motion near a Sphere Compression Wave Generated When a Train Enters a Tunnel Hydrogen-rich alternative fuels are likely to play a significant role in future power generation systems.
The emergence of the integrated gasification combined cycle (IGCC) as one of the favored technologies for incorporating carbon capture into coal-based power plants increases the need for gas turbine combustors which can operate on a range of fuels, particularly syngas, a hydrogen-rich fuel.
2 days ago The analytical solution for the propagation of the laser beam with optical vortex through the system of lenses is presented. The optical vortex is introduced into the laser beam (described as Gaussian beam) by spiral phase plate. The solution is general as it holds for the optical vortex of any integer topological charge, the off-axis position of the spiral phase plate and any number of lenses.
certain fundamental mechanisms of turbulent diffusion flames which form the basis of many propulsion dev-ices. Since acoustic waves are always present in these combustion systems, the role of acoustics in such flame/vortex interactions was investigated (Jackson, Macaraeg and Hussaini, ).
The acoustic field was. Combustion instability, the coupling between flame heat release rate oscillations and combustor acoustics, is a significant issue in the operation of gas turbine combustors. This coupling is often driven by oscillations in the flow field.Abstract This paper reviews the occurrence of the precessing vortex core (PVC) and other instabilities, which occur in, swirl combustion systems whilst identifying mechanisms, which allows coupling between the acoustics, combustion and swirling flow dynamics to occur.
Initially, the occurrence of the PVC in free and confined isothermal flows is reviewed by describing its occurrence in terms of.Unsteady helical flow structures, such as the precessing vortex core (PVC), are often observed in swirling flows with vortex breakdown.
Although this type of flow is of high relevance for industrial combustors, the role of these flow instabilities in reacting systems, in particular their effect on flame stabilization and combustion instabilities, remains poorly understood.