Control of combustion instability with a high-momentum air-jet

Mitigation of thermoacoustic instability utilizing steady air injection near the flame anchoring zone

“…The potential for suppressing thermoacoustic instability by injecting steady air [11,15,16], or by injecting open-loop, low-frequency modulated air [17] near the flame anchoring zone has been shown in the past. In these approaches, the secondary air flow is thought to change the velocity field and disrupt the flame-vortex interaction, which has been shown to be the primary instability mechanism in dump combustors [18].…”

Fundamentals and Applications of Modern Flow Control

“…Examples of actuators used to achieve these physical property changes (note that these same actuators can be and are used in the closed-loop studies as well) include valves that oscillate the air (or fuel) fl ow rate into the combustor (e.g., Bloxsidge et al, 1988;Tuncer et al, 2005;Uhm and Acharya, 2004), speakers that excite acoustic oscillations with desired phase and amplitude within the combustor (e.g., Paschereit et al, 1999), synthetic jet actuators (Ritchie et al, 2000) that introduce vortical features at the small scale to enhance mixing, and secondary or primary fuel injection manipulations (e.g., Auer et al, 2005;Barbosa et al, 2007;Cohen and Rey, 1999;Cohen et al, 2001;Ghoniem et al, 2005;Gutmark et al, 1998;Hathout et al, 2002;Jones et al, 1999;Kim et al, 2000;Lal et al, 2003aLal et al, , 2004Lang et al, 1987;Langhorne et al, 1990;Richards et al, 1999;Yi and Gutmark, 2007a, b;Yu and Wilson, 2002;Yu et al, 1996;Zinn and Neumeier, 1997) that modulate the injection rate of all or a fraction of the supplied fuel. As this reference list suggests, controlling the fuel fl ow rate or modulating the fuel (primary or secondary) has become a major area of ACS for combustion control since this approach directly targets the source of combustion.…”

Investigation of Combustion Control in a Dump Combustor Using the Feedback Free Fluidic Oscillator

“…This method works to control the buildup of unburned propellants that contribute to periodic heat release. 2 Other active control methods include, but are not limited to; variable geometry, 3 secondary fuel injection, [4][5][6][7] high velocity air jets, [8][9][10][11] and arrays of micro actuators. 12 Active combustion control can be implemented in either an open loop or closed loop control system.…”