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

Spatio-Temporal complexity Strogatz

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

Chaos to Limit Cycle via Intermittency Nair and Sujith (2014) 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

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.

Cold flow PIV on bluff body Instantaneous velocity flow field Air Flow Oil seeding Lazkin Nozzle Δ t = 100 μ s

What can we learn from the flame dynamics • Mie Scattering – Unburnt reactants • Chemiluminescence Imaging – Reaction zone

Combustion Noise Intermittency Swirl Instability Before Blowout

Combustion Noise Intermittency Bluff Instability

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