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چکیده
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Circulating fluidized bed boilers are inherently nonlinear systems in which symmetric configurations may evolve toward different flow states under disturbance amplification. Inspired by nonlinear stability theory and symmetry-breaking behavior, this study investigates whether spatially structured non-uniform fluidizing air can act as a controllable perturbation to reorganize flow evolution and regulate symmetry-breaking behavior in an industrial-scale circulating fluidized bed boiler. A multiphase particle-in-cell model coupled with large eddy simulation was employed to simulate gas–solid flow under five fluidizing air distributions with identical mean inlet velocity. Pressure and voidage signals extracted from symmetric monitoring locations were analyzed using phase-space reconstruction, correlation dimension, and Kolmogorov entropy. The results show that different non-uniform air distributions produce fundamentally different nonlinear responses. Some patterns expand attractors, fragment trajectories, and intensify information loss in the combustion (1–5 m) and burnout (5–15 m) zones, indicating enhanced instability and symmetry breaking. The maximum correlation-dimension difference between symmetric locations reached 0.16 under asymmetric forcing. However, other non-uniform patterns generated more organized attractors and lower entropy growth, suggesting that spatially structured disturbances can regulate disturbance propagation rather than simply deteriorate flow stability. Among the investigated cases, the high–low–high distribution produced the strongest chaotic response, whereas the short-side low–high–low pattern exhibited comparatively moderate nonlinear behavior. This work integrates MP-PIC–LES simulation with nonlinear dynamic diagnostics and demonstrates that non-uniform fluidizing air can serve as a controllable boundary perturbation for regulating symmetry breaking and dynamic stability in industrial-scale CFB boilers.
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