Linear and non-linear pressure oscillations in baffled combustion chambers

Dynamics and stability of lean-premixed swirl-stabilized combustion

“…A typical configuration consists of flat plates extending into a chamber perpendicularly from the injector face. Three mechanisms (Reardon[316], Combs et al[317], Wicker et al[318]) have been proposed for explaining successful elimination of instability by baffles: (1) modification of acoustic resonance properties (i.e., frequency and waveform); (2) restriction of unsteady motion between baffle blades, and subsequent shielding of the sensitive mechanisms for instabilities; and (3) damping of oscillations by vortex shedding, flow separation, and viscous dissipation. Baffles have been widely used in rocket engines since 1954 (Male et al[319]), but their use in gas turbine engines is rare.…”

Stability rating tests for the length-optimization of baffles in a liquid propellant combustion chamber using a pulse gun

“…Moreover, it is known that there is the longitudinalization of transversal acoustic modes in the baffle tip region [16,17], so a stiff pressure gradient can occur near the baffle tip, observed easily in Fig. 8(b), which shows the acoustic pressure contours of the first tangential mode.…”

“…Hydrodynamic characteristics of a F-O-O-F impinging injector[13] and acoustic field illustrating a possible acoustic-flame coupling[16,17]. (a) Hydrodynamic characteristics of a present injector.…”

Self-excited Oscillations and Fuel Control of a Combustion Process in a Rijke Tube

“…In contrast with formalism of linear acoustics, the nonlinear acoustics is applied at very high release rates, which allows the treatment of interactions between the shock waves and combustion (Rudinger [31], McManus et al [23], Ducruix et al [13]). Second order linear and nonlinear acoustic wave analyses, respectively for two-and three-dimensional baffled combustion chambers have been developed by Wicker et al [34]. Due to the presented nonlinear coupling between linear acoustics and heat release rate, theoretically an infinite number of acoustic modes exist.…”