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Bifurcation structure of the flame oscillation
Yuki Araya1, Hiroaki Ito1, Hiroyuki Kitahata1
1Department of Physics, Chiba University, Chiba 263-8522, Japan.
Physical Review. E
|May 20, 2022
Summary
Flame flickering, a limit-cycle oscillation, was studied using simulation and experiments. Researchers found that flame oscillation appears via a subcritical Andronov-Hopf bifurcation, with amplitude increasing and frequency decreasing as fuel-inlet diameter grows.
Area of Science:
- Fluid dynamics
- Combustion science
- Nonlinear dynamics
Background:
- Flame flickering, or limit-cycle oscillation, occurs under specific conditions.
- Understanding the bifurcation structure of flame oscillation is crucial for controlling combustion processes.
Purpose of the Study:
- To investigate the bifurcation structure of flame oscillation in both simulation and experiment.
- To analyze the parameter dependencies of oscillation amplitude and frequency on fuel-inlet diameter.
- To elucidate the underlying mechanisms of flame flickering.
Main Methods:
- Performed a two-dimensional hydrodynamic simulation using the flame sheet model.
- Developed an experimental system to precisely control fuel-inlet diameter.
- Observed hysteresis, bistability, and state switching in both simulation and experiment.
Main Results:
- Reproduced flame oscillation and confirmed parameter dependencies on fuel-inlet diameter.
- Observed hysteresis and bistability between stationary and oscillatory flame states.
- Demonstrated that increased fuel-inlet diameter leads to increased amplitude and decreased frequency of oscillation.
Conclusions:
- Concluded that flame oscillation emerges from a stationary state via a subcritical Andronov-Hopf bifurcation.
- Confirmed the bistability of stationary and oscillatory states, with fluctuations inducing state switching.
- Visualized vortex structures to discuss their influence on flame dynamics.
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