Mean-field model of synchronization for open-loop, swirl controlled thermoacoustic system

Area of Science:

• Fluid Dynamics
• Nonlinear Dynamics
• Combustion Science

Background:

• Thermoacoustic instability, characterized by self-excited oscillations, is a significant challenge in turbulent combustors.
• Open-loop control strategies are effective but require precise modeling of complex dynamics.

Purpose of the Study:

• To experimentally observe and model the suppression of thermoacoustic instability using swirler rotation.
• To investigate the transition from limit cycle oscillations to aperiodic states via intermittency.
• To develop a synchronization model that captures the underlying spatiotemporal dynamics.

Main Methods:

• Experimental investigation of a lab-scale turbulent combustor with a rotating swirler.
• Extension of an existing phase oscillator model to include acoustic feedback.
• Quantitative validation using optimization algorithms for parameter estimation.

Main Results:

• Progressive swirler rotation induces a transition from limit cycle to aperiodic oscillations.
• The extended model accurately replicates bifurcation characteristics and nonlinear time series features.
• Spatiotemporal synchronization between heat release and acoustic pressure was identified as key to suppression.

Conclusions:

• Swirler rotation provides an effective open-loop control for thermoacoustic instability.
• The developed synchronization model offers a powerful tool for understanding and controlling instabilities in fluid systems.
• The model's ability to capture spatiotemporal synchronization highlights its potential for diverse dynamical systems.