...Lipika Kabiraj; R. I. Sujith; Pankaj Wahi Bifurcation analysis is performed on experimental data obtained from a simple setup comprising ducted laminar premixed conical flames in order to investigate the features of nonlinear thermoacoustic oscillations. It is observed that as the bifurcation...

... influence on the surface behavior of the Li flow in the downstream region. Experiments were carried out with a focus on surface oscillations of the Li flow using the lithium circulation loop at Osaka University. These oscillations are measured using an electro-contact probe apparatus, which can detect...

.... As in annular combustors, the particularly critical eigenmodes with low frequencies are predominantly of circumferential nature; the stability of annular combustors is often governed by the onset of circumferential acoustic oscillations. To determine the influence of these circumferential acoustic modes...

... acoustics and heat release that drives the oscillation. Compared to the closed-loop case, this approach has some advantages because it may not require high-fidelity fuel actuators, and could be easier to implement. This paper reports experimental tests of open-loop fuel perturbations to control combustion...

... air shear layer or the fuel line, with less than 1.0% of combustion air, can reduce pressure oscillations amplitude by more than 20 dB . Phase-shifted close-loop air forcing of the flame can reduce the pressure oscillations amplitude by 13 dB . For a constant air flow rate and air inlet temperature...

... to fuel splits or operating conditions unless, of course, pressure oscillations are actually present. We have developed a methodology for ascertaining the stability margin from dynamic pressure data that does not require external forcing and that works even when pressure oscillations have very low...

... on No. 2 diesel fuel (DF2). Emissions, oscillations and lean blowout (LBO) performance on liquid fuel at high, part and no load operating points (pressures of 160, 100, 120 psig, and inlet temperatures of 690, 570, 590°F, respectively) and various pressure drops (ΔP/P) and air fuel ratio conditions were...

... permanently purging the resonator in order to avoid overheating. Once the damper has been designed, its impedance applied to the enclosure permits to simulate the pressure field in the system for a given excitation. For combustion applications, dampers modeled as harmonic oscillators have been coupled...

... of density wave oscillations is analyzed. 01 10 2003 01 03 2004 boilers heat recovery flow instability oscillations pipe flow Steam generators with natural circulation have a wide range of applications, such as industrial heating processes or power cycles. Many of these natural...

...M. P. Auer; C. Gebauer; K. G. Mösl; C. Hirsch; T. Sattelmayer Modern low-emission premix combustion systems are often susceptible to combustion instabilities. Active instability control (AIC) systems are commonly used to attenuate these oscillations. For the control authority of AIC systems...

... at the (nearly) choked combustor outlet are supposed to be the key feedback mechanism for the observed self-excited pressure oscillations. The experimental study presented here aims at clarifying the role of entropy waves in the occurrence of rumble. A generic air-blast atomizer with a design prone to self...

...T. Sattelmayer Gas turbine combustors are often susceptible to self-excited oscillations, which lead to unacceptable levels of pressure, velocity, and heat release fluctuations. Although instabilities can occur in systems with locally constant equivalence ratio, it is very important to take...

... experimenteller Analyse von Brennkammerschwingungen,” PhD thesis, RWTH Aachen. Fleifil , M. , Annaswamy , A. M. , Ghoneim , Z. A. , and Ghoniem , A. F. , 1996 , “ Response of a Laminar Premixed Flame to Flow Oscillations: A Kinematic Model and Thermoacoustic Instability Results ,” Combust...

...C. O. Paschereit; B. Schuermans; W. Polifke; O. Mattson An experimental method to determine the thermoacoustic properties of a gas turbine combustor using a lean-premixed low emission swirl stabilized burner is presented. To model thermoacoustic oscillations, a combustion system can be described...

...M. Zhu; A. P. Dowling; K. N. C. Bray Combustors with fuel-spray atomizers are susceptible to a low-frequency oscillation, particularly at idle and sub-idle conditions. For aero-engine combustors, the frequency of this oscillation is typically in the range 50–120 Hz and is commonly called “rumble...

... oscillations which must be eliminated before the release of a final combustor design. In order to eliminate the pressure oscillations the location of fuel injection was parametrically evaluated to determine a stable configuration. It was observed that small axial changes in the position of the fuel spokes...

...Stanley S. Sattinger; Yedidia Neumeier; Aharon Nabi; Ben T. Zinn; David J. Amos; Douglas D. Darling Described are sub-scale tests that successfully demonstrate active feedback control as a means of suppressing damaging combustion oscillations in natural-gas-fueled, lean-premix combustors...

...M. Zhu; A. P. Dowling; K. N. C. Bray Most types of combustion-driven devices experience combustion instabilities. For aeroengine combustors, the frequency of this oscillation is typically in the range 60–120 Hz and is commonly called “rumble.” The rumble oscillations involve coupling between...