Dr. Ann Karagozian

Distinguished Professor, Vice Chair Industry Relations and Outreach 

Dept. Of Mechanical and Aerospace Engineering 

University of California, Los Angeles 

Bio: Dr. Ann R. Karagozian is a Distinguished Professor and the Collins Aerospace Term Chair for Innovation in the Department of Mechanical and Aerospace Engineering at the University of California, Los Angeles. Her research interests lie in fluid mechanics and combustion as applied to advanced rocket and air breathing propulsion systems. She is the Director of the UCLA MAE Energy and Propulsion Research Laboratory, the UCLA-Air Force Research Laboratory Collaborative Center for Aerospace Sciences, and is the Inaugural Director of the UCLA Promise Armenian Institute. She is a Member of the National Academy of Engineering, and is a Fellow of the American Institute of Aeronautics and Astronautics (AIAA), the American Physical Society (APS), and the American Society of Mechanical Engineers (ASME). Professor Karagozian is currently a member of the U.S. Defense Science Board and in the past was a member (and Vice Chair) of the U.S. Air Force Scientific Advisory Board. She is also a member of the Board of Trustees of the Institute for Defense Analyses (IDA) and a mentor for IDA’s Defense Science Study Group. She received her B.S. in Engineering from UCLA and her M.S. and Ph.D. in Mechanical Engineering from the California Institute of Technology.

Topic: Dynamics of Acoustically Coupled Combustion Instabilities 

Abstract: Acoustically-coupled combustion instabilities can result in large scale, potentially catastrophic pressure oscillations in aerospace propulsion systems, including liquid rocket engines (LREs) and gas turbine engines. A fundamental understanding of the interactions among flow and flame hydrodynamics, acoustics, and reaction kinetics is essential to determining combustor stability and controlling combustion processes. Over the past several years our group at UCLA has been pursuing fundamental experiments that can shed light on combustion instabilities and their control, including exploration of the effects of external acoustic perturbations on liquid nanofuel combustion and, more recently, gas-phase fuel jet combustion with alternative injector configurations. The dynamics of phenomena such as periodic liftoff and reattachment, periodic partial extinction and reignition, and full extinction are explored and quantified via phase-locked OH* chemiluminescence and high speed visible imaging. Proper orthogonal decomposition (POD) analysis and associated phase portraits enable extraction of characteristic signatures associated with different flame phenomena. Understanding such signatures enables development of reduced order models that can impact eventual combustion control strategies.

Thursday, March 13, 2025

102 BEH

11:00am

Host: Peyman Givi