Abstract :

Two Problems in Turbulent Combustion: Turbulent Flame Speed and Flame Blowoff Turbulent combustion is one of the most crucial yet poorly understood phenomena, ubiquitous in any practical chemical propulsion system. In this seminar, experimental and theoretical works on two fundamentally important problems pertinent to turbulent premixed combustion would be presented. These are flame propagation characterized by turbulent flame speed and loss of flame stabilization by local and global extinction i.e. flame blowoff. First, theoretical aspects of turbulent flame propagation using spectral closure of flame surface level set equation would be examined. These theoretical studies would then be thoroughly substantiated with state of the art experiments in a unique constant pressure flame propagation vessel in near homogenous isotropic turbulence. In particular, the normalized turbulent flame speed is shown to successfully scale with a turbulent Reynolds number to the power one-half, where the Reynolds number is based on flame length scales and transport properties. For the second problem, the blowoff mechanism of bluff body stabilized turbulent premixed flames would be investigated using detailed experiments utilizing simultaneous Particle Image Velocimetry and Planar Laser Induced Fluorescence of Hydroxyl radical. Bio-sketch:Swetaprovo Chaudhuri is an Assistant Professor at the Department of Aerospace Engineering, IISc since June 2013. Prior to this appointment he was a research staff with Prof. C. K. Law in the Department of Mechanical and Aerospace Engineering at Princeton University and the Department of Energy sponsored Combustion Energy Frontier Research Center. He earned his Ph.D. from the University of Connecticut in 2010 with Prof. B. M. Cetegen and B.M. E. from Jadavpur University in 2006, both in Mechanical Engineering.