Task 2.3 Experimental study of turbulent swirl combustor Nitin Babu - - PowerPoint PPT Presentation

Task 2.3 Experimental study of turbulent swirl combustor

Nitin Babu George Acknowledgement : Prof R. I. Sujith and our Team

Recap - Task 2.3

Experimental study of turbulent swirl combustor

Ack: Polifke & Komarek (TUM)

Simultaneous PIV and Chemiluminescence data Spatio-Temporal Analysis Lack of Hysteresis in swirl stabilized flames Relook at Hopf Bifurcations

Strogatz

Spatio-Temporal complexity

Critical transitions happen if a system shifts from one attractor to another

Scheffer

Present Scenario

Can we have a unified framework? Scheffer

Intermittency is present in many spatio-temporal systems

Nair & Sujith (2014) Drepper et al (1994) Touboul et al (2011)

Chaos to Limit Cycle via Intermittency

In dynamical systems, intermittency is the irregular alternation of phases of apparently periodic and chaotic dynamics (Pomeau–Manneville dynamics), or different forms of chaotic dynamics (crisis-induced intermittency). Edward Ott (2002) Mingzhou Ding. Alwyn Scott Nair and Sujith (2014)

Is the turbulent flow field responsible for intermittency in turbulent combustors?

Intermittent behavior is commonly observed in fluid flows that are turbulent or near the transition to turbulence. Intermittency has been observed in aero-acoustic systems also.

Instantaneous velocity flow field Oil seeding Lazkin Nozzle Air Flow Δt = 100 μs

Cold flow PIV on bluff body

What can we learn from the flame dynamics

• Mie Scattering – Unburnt reactants
• Chemiluminescence Imaging – Reaction zone

Combustion Noise Intermittency Instability Before Blowout Swirl

Combustion Noise Intermittency Instability Bluff

Next stage

• Swirler Configuration
• Hot Flow PIV – Aluminium oxide seeding

Spatial Analysis – Flame Behavior and Velocity field Secondment at TUM – Discussion ongoing

• March/April 2016
• Conjugate heat transfer problem at the flame holder – Possibility of

capturing intermittency

Thank you