Chaos in an imperfectly premixed model combustor

Area of Science:

• Fluid dynamics
• Nonlinear dynamics
• Combustion science

Background:

• Thermoacoustic instabilities are common in combustors and can lead to system failure.
• Previous studies have identified bifurcation scenarios in laminar premixed flame combustors.
• Understanding these instabilities is crucial for designing stable and efficient combustion systems.

Purpose of the Study:

• To investigate nonlinear bifurcations in a laboratory-scale turbulent combustor.
• To identify the route to chaos in thermoacoustic instability dynamics.
• To extend previous findings from laminar to turbulent combustor configurations.

Main Methods:

• Experimental analysis of a turbulent combustor operating in an imperfectly premixed mode.
• Utilizing the global equivalence ratio as the control parameter.
• Observing nonlinear bifurcations and characterizing the resulting dynamics.

Main Results:

• Nonlinear bifurcations were observed in the turbulent combustor.
• The dynamics of thermoacoustic instability were found to follow a quasi-periodic route to low-dimensional, deterministic chaos.
• These results align with observations in laminar premixed flame combustors.

Conclusions:

• The study confirms that thermoacoustic instability in turbulent combustors can exhibit deterministic chaos.
• The observed route to chaos is consistent with general principles of dissipative nonlinear systems.
• This research validates and extends prior findings to a more practically relevant turbulent combustor setting.