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2 edition of An investigation of the effect of a tangential gas velocity on combustion instability found in the catalog.

An investigation of the effect of a tangential gas velocity on combustion instability

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Published by Naval Postgraduate School in Monterey, California .
Written in English

    Subjects:
  • Aeronautics

  • ID Numbers
    Open LibraryOL25128802M

    Fig.5 Effects of spray velocity on stability of conical sheet (h. 0=mm, β=45º, r 0=mm) Summary. A linear instability theoretical model is used to predict the instability of a conical liquid sheet. The model incorporates essential features of the liquid sheet downstream of a swirl injector. As the swirl. Combustion occurs when the reactants leaving the exit nozzle, a significant increase in axial velocity results from hot gas expansion. An increase in radial velocity also occurs. The combined tangential and axial momentum of the products results in flow spreading in the and directions on the plane by: Good agreement of the calculation and theoretical results of the velocity profiles and pressure distributions was obtained. Iyogun et al. presented an experimental investigation on the stability of swirling non-premixed CH 4 flames in a coaxial burner. Measurements were conducted for both reacting and non-reacting swirling : Toufik Boushaki. In the present investigation, various factors and trends, related to the usage of two or more sets of inert particles comprised of the same material (nominally aluminum) but at different diameters for the suppression of axial shock wave development, are numerically predicted for a composite-propellant cylindrical-grain solid rocket motor. The limit pressure wave magnitudes at a later Cited by: 4.

    This research investigation encompasses expanded testing of a high-frequency combustion instability suppression technique, in which an instability is .


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An investigation of the effect of a tangential gas velocity on combustion instability by Joseph Alan Kiel Download PDF EPUB FB2

Gas velocity toward initiating oscillations remain un­ resolved. THEORETICAL COMBUSTION STUDIES WITH TANGENTIAL VELOCITY The effect of a steady vortex velocity on stability boundaries in a toroidal combustor has been calculated in reference 5 for a vaporization-limited combustion model.

The re­ sults taken from reference 5 are shown in figure Size: KB. Approved for public release; distribution in unlimited.A small, uncooled liquid rocket motor was utilized to examine the effects of the magnitude and direction of a steady vortex velocity on combustion instability.

The rocket operated on normal heptane and air, with air flow rates controllable to allow for various amounts of tangential : Donald William Avery.

A first tangential high frequency mode of combustion instability was developed and a significant change in stability conditions was found when a vortex flow was generated within the combustion : Joseph Alan Kiel. diameter, D, the bulk mean velocity, Umean, and the dynamic air viscosity, μ.

The swirl generator is of axial-plus-tangential entry type, it allows changing swirl intensity by varying the axial and tangential flow rates of air by means of thermal mass flow meters with 1% accuracy. The axial air enters through four radial inlets in. The effects of combustion instability on flow structure and flame dynamics with the inlet configurations in a model gas turbine combustor were investigated.

Effect of fuel–air mixture velocity on combustion instability of a model gas turbine combustor Article in Applied Thermal Engineering 54(1)– May. phenomenon is a great barrier in development of gas turbines with premixed combustion capability using natural gas.

Hobson et al. [1], in a study conducted on a silo combustor, developed a theoretical model which has been used to derive some generic characteristics of combustion instability in terms of damping ratio.

In this study, the combustion gas temperature inside the combustor increases by increasing the fuel–air mixture velocity since the heat dissipation rate remains constant. Fig. 4 can be easily separated into the three parts of low velocity instability, stable, and high velocity instability regions.

The instability frequency and temperature of the combustion chamber Cited by: which the mean flow velocity, the stability of standing pressure oscillations were changed due to the distribution of combustion product during steady operation[4].

The vortices generated by acoustic oscillations were second order viscous effect, and tangential modes gave a single vortex swirling about their axisCited by: 1. Pancharia, Pankaj, Ramanan, Vikram, Nagarajan, Baladandayuthapani, and Chakravarthy, S. "Investigation on Effect of Inlet Flow Turbulence on the Combustion Instability Using Simultaneous PIV and CH* Chemiluminescence in a Backward Facing Step Combustor." Proceedings of the ASME Turbo Expo Turbomachinery Technical Author: Pankaj Pancharia, Vikram Ramanan, Baladandayuthapani Nagarajan, S.

Chakravarthy. The double-swirler, double-channel annular burner was specially designed to generate acoustic velocity oscillations and radial fuel stratification at the inlet of the combustion chamber.

Temporal oscillations of equivalence ratio along the axial direction are dissipated over a long distance, and therefore the effects of time-varying fuel/air ratio on the flame response are not Cited by: 2. This book provides an excellent illustration of research and development on a selected group of problems relating to detonations, two-phase nozzle flow, and combustion in liquid fuel rocket engines.

This volume is divided into two parts. Annotation Since the invention of the V-2 rocket during World War II, combustion instabilities have been recognized as one of the most difficult problems in the development of liquid propellant rocket engines.

This book is the first published in the United States on the subject since NASA's Liquid Rocket Combustion Instability (NASA SP) in /5(1). This book offers gas turbine users and manufacturers a valuable resource to help them sort through issues associated with combustion instabilities.

In the last ten years, substantial efforts have been made in the industrial, governmental, and academic communities to understand the unique issues associated with combustion instabilities in low. Dynamic instability has long been recognized as a problem in continuous combustion systems.

In several applications, including ramjets, rocket motors, afterburners, and gas turbines, this insta- bility assumes the form of pressure oscillations that have a tendency to grow.

Effect of fuel–air mixture velocity on combustion instability of a model gas turbine combustor Applied Thermal Engineering, Vol. 54, No. 1 Realizable Unified RANS-LES and Dynamic LES Methods for Turbulent Flow SimulationsCited by: Investigation of pressure effects on the small scale wrinkling of turbulent premixed Bunsen flames Romain Fragnera, Fabien Haltera,b,⇑, Nicolas Mazellierb, Christian Chauveaua, Iskender Go¨kalpa aCentre National de la Recherche Scientifique, Institut de Combustion, Ae ´rothermique, Reactivite et Environnement, 1C, Avenue de la Recherche Scientifique.

INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 4, IS DECEMBER ISSN CFD Investigation Of The Effect Of Tilt Angles To Flow And Combustion In A Mw Gas. The present study has experimentally investigated the combustion instability and its attenuation characteristics in the lab-scale swirlstabilized premixed combustor with a sponge-like porous medium.

Unlike the conventional premixed burners, this model combustor has the unique features including a porous dump plane and an acoustic cavity, which was devised for attenuating the combustion Cited by: 3. Fred S. Blomshield 1 Naval Air Warfare Center Weapons Division, China Lake, CA, Over the last 60 years, a considerable amount of time and money has been spent improving our understanding of combustion instability in solid rocket propulsion by: Spray combustion is an inherently unstable mechanism because of the.

unsteadiness involved in the evolution of sprays. Further, spray combustion cannot be. truly designated as premixed or as diffusion combustion process as in the case of. gaseous combustion. The biggest among them was combustion a candle flickering from side to side as it seeks oxygen to burn, the single chamber F-1 engine multiplies that flicker into million pounds of exploding thrust (the previous front runner at just over one-tenth of that power, the H-1 engine, came in at a merepounds of thrust).

A Driving Mechanism for High Frequency Combustion Instability in Liquid Fuel Rocket Engines - Volume 68 Issue - P. McCormack A Driving Mechanism for High Frequency Combustion Instability in Liquid Fuel Rocket Engines.

McCormack (a1) An Investigation of the Effect of Mechanical Vibration on Liquid Jet Break-up by: 4. The higher inlet velocity, results in the higher tangential velocity, thus leading to a higher centrifugal force and collection efficiency. Patterson and Munz () analyzed the effect of several parameters including the gas temperature (K - K), inlet gas velocities (3 m/s – 42 m/s) and particle loadings (up to g/m 3) on the Cited by: 1G Effect of pressure on the combustion of an aqueous urea and ammonium nitrate monofuel B.

Mosevitzky, M. Epstein, G.E. Shter, G.S. Grader 1H Thermo-acoustic instabilities driven by fuel droplet lifetime oscillations A. Genot, S. Gallier, T. Schuller 1J Effect of steam on the single particle ignition of solid fuels in a dropFile Size: 1MB. T1 - Combustion instability in gas turbines. T2 - AIAA Aerospace Sciences Meeting, AU - Taha, Ahmed.

AU - Vellakal, Madhu. AU - Lu, Qiyue. PY - /1/1. Y1 - /1/1. N2 - Combustion instability is a major problem to be solved in the gas turbine : Ahmed Taha, Madhu C. Vellakal, Quiyue Lu. tangential gas velocity, which resulted in a larger amount of energy addition during the high-pressure portion of the cycle than during the low-pressure portion.

Both solid (ref. 4) and liquid (ref. 5) motors have been driven unstable when high. This paper present a series of experiments using a well-characterised tangential swirl burner to investigate the effect of using diffusive air injection on flow field characteristics and how it can affect the lower instability limits through altering the flashback mechanism by Combustion Induced Vortex Breakdown (CIVB).Author: Fares Amer Hatem, Ali Safa Alsaegh, Agustin Valera Medina, Nick Syred, Richard Marsh.

instability and experimental combustion tests confirm that the new system is free of combustion instability. Introduction High-pressure core used for the development of gas turbines is constituted of the association of a combustor chamber, a high-pressure compressor and a high-pressure turbine (Fig.

Such devices are very useful for engineCited by:   We extend the Michelson–Sivashinsky equation, for arbitrary gas density ratio, to model the dynamics of an inclined anchored flame front. A flow velocity component tangential to the flame front transforms temporally developing structures into spatially developing ones.

Closer investigation shows that a transition from absolute to convective instability should occur for a finite flow by: An experimental study was conducted to identify the combustion instability mechanisms of flame-vortex interactions and equivalence ratio fluctuations and to characterize the combined effects of the two mechanisms on self-excited unstable combustion in a swirl-stabilized lean-premixed gas turbine by: 6.

The effect of velocity ratio [LAMBDA] on the absolute instability of an inviscid shear layer is illustrated in Figure 3. It appears in Figure 3 that the absolute growth rate increases with the increases of velocity ratio [LAMBDA].

In particular, when the velocity ratio is larger thanthe absolute growth rate becomes positive. Experimental Investigation of Acoustic Instabilities in Laminar Premixed Flames. The coupling mechanism that we propose to explain the instability proceeds via the acoustic velocity field and is parametric in nature.

J.C., (), Interaction between combustion and gas motion in the case of flames propagating in tubes., Astronautica Cited by: 3. A turbulent premixed plane jet flame is analyzed by large-eddy simulations.

The analysis shows that the flame front wrinkling is strongly influenced by the shear layer effect when the gas expansion effects are small leading to larger flame front amplitudes at the flame base than at high gas expansion ratios.

However, the hydrodynamic instability effect induces a Cited by: 9. The kW tangential swirl burner used in this work is illustrated in Figure 1. Many investigations on swirling flow stability have been performed using this combustion system [12, 16, 17]. The burner has two tangential inlets of 67 mm in diameter; the exit diameter is 78 mm.

The diameter of the tangential inlets can be. well established that combustion response (i.e., the coefficients (Xc and wc) varies with frequency. Therefore, the degree to which combustion destabilizes a mode depends on the frequency of the mode itself.

If the energy gain due to combustion response is greater than energy damping, then an instability of the particular mode results. In this work, the effects of the electric fields on the flame propagation and combustion characteristics of lean premixed methane–air mixtures were experimentally investigated in a constant volume chamber.

Results show that the flame front is remarkably stretched by the applied electric field, the stretched flame propagation velocity and the average flame propagation velocity Cited by: 9. Combustion evolution has been simulated using an improved version of KIVA 3V [1, 2].To take properly into account one of the major sources of the combustion instability a detailed spark ignition and initial flame kernel formation model [3] has been implemented in the fluid-dynamics 3D varying the value of some input parameters in a stochastic Cited by: 7.

This book offers gas turbine users and manufacturers a valuable resource to help them sort through issues associated with combustion instabilities. In the last ten years, substantial efforts have been made in the industrial, governmental, and academic communities to understand the unique issues associated with combustion instabilities in low-emission gas turbines.

Diffusive-thermal instability thus has a pronounced influence on the unstable behavior and burning velocity of nonadiabatic cellular flames.}, doi = {/tflame}, journal = {Combustion and Flame}, issn = {}, number = 3, volume =place = {United States}, year = {Tue Nov 01 EST }, month = {Tue.

The effects of H{sub 2} enrichment on the propagation of laminar CH{sub 4}-air triple flames in axisymmetric coflowing jets are numerically investigated.

A comprehensive, time-dependent computational model, which employs a detailed description of chemistry and transport, is .and third-order nonlinear gas dynamics and combustion response. Results suggest three important effects of baffles on transverse modes of combustion instability.

First, transverse waves can be longitudinalized inside baffle compartments. This may decouple combustion response from oscillatory motions if the processes nearFile Size: 4MB.tangential velocity profiles obtained based on these turbulence models are “Investigation of the flow pattern in different dust outlet geometries of a gas cyclone by laser Doppler anemometry,” Estimation of numerical errors and the effect of gas phase turbulence modeling in Euler -Lagrange models of multi-phase.