報告題目：發動機燃燒不穩定性與基于物理信息神經網絡的研究與應用

報 告 人：趙丹

報告時間：2025年2月27日下午2:00

報告地點：S404

專家簡介：

      趙丹教授，新西蘭皇家科學院與工程院兩院院士，歐洲科學院外籍院士，歐洲科學與藝術院外籍院士，博士畢業于英國劍橋大學，目前擔任新西蘭皇家學會院士評選委員，新西蘭坎特伯雷大學機械學院教授，博士生導師，兼研究生招生辦主任，國際聲學與振動學會杰出會士（美國），中國僑聯特聘專家委員會委員，教育部 111 計劃學術大師。長期從事下一代零碳（氨、氫）排放發動機燃燒、無人機、空氣動力學與噪音、燃氣輪機以及航空航天推進系統熱聲不穩定性以及控制的研究。在國際SCI期刊發表論文300 余篇，出版英文專著4本，英文教材1本（第八版），專利 5 項，擔任國際和國內多個期刊的主編或副主編，SCOPUSH-因子6。

報告內容：Self-sustained thermoacoustic oscillations as observed in low-emission combustion-involved gas turbines and aero-engines involve complicated thermal-fluid-acoustics interaction and rich nonlinear dynamics. Such pulsating oscillations are known as thermoacoustic instability. When it occurs, large-amplitude limit cycle oscillations (LCOs) of thermodynamic parameters are frequently observed. LCOs could cause overheating, flame flashback, and even engine failures. Thus, it is critical to understand and predict the generation mechanisms, nonlinear dynamics behaviors and then develop corresponding control approaches to prevent or control the onset of such instabilities. For this, we develop and extend the conventional Van der Pol (VDP) oscillators by integrating PINNs (Physics-informed neural networks) algorithm with a modeled nonlinear Rijke-type thermoacoustic combustor. The theoretical Rijke tube system (with Galerkin expansion and modified King’s Law implemented) and a CFD simulation model are applied to provide ‘training/calibration data’ for the EVDP (extended VDP)-PINNs model. The optimized EVDP oscillators are confirmed to be capable to capture the key nonlinear characteristics by comparing the transient growth behaviors of thermodynamic perturbations and LCOs’ amplitude and frequency. Further investigations are conducted to obtain Hopf bifurcation and amplitude death (AD) characteristics. Comparison is then made to the coupled EVDP systems. Quite similar Hopf bifurcation features, but differences in regions of AD, are observed In general, we demonstrate an applicable approach to intelligently ‘learn’ a nonlinear thermoacoustic system and to create reliable EVDP oscillator systems, which have great potential to contribute to the development and testing of control approaches, such as the coupling described above, which may replace costly experimental tests.