报告题目：Nnonlinear Dynamics of Swirling Thermoacoustic Combustors(旋流燃烧器非线性特性研究)
主讲人概况：Dr. Dan Zhaois a tenured professor and Director of Master Engineering Studies in the University of Canterbury, New Zealand. He graduated from the University of Cambridge and the University of Manchester with a PhD and Master degree in 2009 and 2004, respectively.
Currently, he is the chief editor of SCI-IndexedInternational Journal of Aerospace Engineering; Associated Editor of 6 archived SCI-indexed journals, such asAIAAJournal, Aerospace Science and Technology, Journal of the Royal Society of New Zealand (新西兰科学院院刊), J. Low Freq. Noise, Vib. Act. Control, Progress in Aerospace Sciences, Journal of Thermal Sciences(中科院热科学学报); 1 EI-indexed journal of Propulsion Technology (推进技术).
His research interests andexperienceinclude Aeroacoustics, Aerodynamics, Energy Harvesting, passive and active control, and Combustion and Propulsion. He has co-authored 1 books, 5 review papers, more than 20 conference papers and more than 120 SCI citation papers in peer reviewed international journals.
报告摘要：To more and more stringent combustion emission requirements, lean premixed combustion technology is widely applied in modern propulsion and power generation combustion systems. However, under such lean conditions, these gas turbines and aero-engines are more susceptible to combustion instability, which is characterized by large amplitude pressure oscillations. The present work considers experimental investigation of the effects 1) the equivalence ratio, 2) inlet air flow rate and 3) swirling number on generating thermoaocustic instability in a premixed swirling combustor. Acoustic pressure measurements are conducted by applying an array of microphones. Bifurcation plots are obtained first, as each of these parameters is varied. Both time-frequency and recurrence plot analysis are then performed. The experimental results reveal that 1) the equivalence ratio, 2) the inlet air flow rate and 3) the swirling number play important roles on producing thermoacoustic limit cycles with different characteristics, i.e. the mode frequency and amplitudes. It is experimentally found that maximum amplitude limit cycles occur, as the equivalence ratio is set between 0.8 and 0.9. Time-frequency analysis shows that not only the dominant mode amplitude but also the dominant mode frequency are dramatically varied. Recurrence plot analysis illustrates that when combustor is operated in the absence of thermoacoustic oscillations, the RP graph is more chaotic. In summary, the present work reveals nonlinear dynamics characteristics and behaviours of a swirling thermoacoustic combustor. These findings are insightful on design a stable but emission-low combustor.