Seminar Series

Synchronization phenomena in a forced self-excited thermoacoustic oscillator

Speaker

Prof Larry Li

Institute

Hong Kong University of Science and Technology

Time & Place

Fri, 21 Jun 2019 14:00:00 NZST in E14 (Lecture Theatre), Engineering CORE

All are welcome

Abstract

‌In many combustion devices, the positive coupling between unsteady heat release and sound can give rise to thermoacoustic instability, resulting in high-amplitude selfexcited flow oscillations in the combustion chamber.  Such thermoacoustic oscillations are undesirable because they can impair flame stability and increase vibration and thermal stresses.  Open-loop forcing is known to be an effective strategy for controlling such oscillations, but the details of this synchronization process have yet to be comprehensively explored.  In this talk, I will present experimental measurements and low-order simulations of the forced synchronization of a prototypical thermoacoustic system - a laminar conical premixed flame in a tube combustor.  I will examine the system's response in a nonlinear dynamical framework, with a focus on the bifurcations leading up to and beyond the synchronization boundaries as well as other nonlinear phenomena such as asynchronous quenching, mode switching, and strange non-chaotic attractors.  Gaining insight into the forced synchronization of self-excited thermoacoustic systems can open up new pathways towards the development of improved strategies for controlling combustion devices such as gas turbines and rocket engines. 

 Larry Li Seminar

Biography

Larry Li Headshot

Prof Larry Li received his BASc and MASc in Mechanical Engineering from the University of British Columbia, where he was a Natural Sciences and Engineering Research Council Scholar in the Applied Fluid Mechanics Laboratory.

He then went on to study for a PhD at the University of Cambridge, where he was a Bill and Melinda Gates Scholar in the Injector Dynamics Group of the Department of Engineering.

After graduating, he stayed on at Cambridge as a Research Associate before joining the Hong Kong University of Science and Technology (HKUST) in 2014 as an Assistant Professor in the Department of Mechanical and Aerospace Engineering.