Towards Smart Laser Diagnostics for Reacting Flows

Abstract

Precision laser diagnostics can provide high-quality experimental data critically needed for the development, validation and optimization of modern fluid mechanics and kinetic models for reacting flows. However, to design feasible, sensitive and information-rich experiments that may yield such data often requires sophisticated planning. This seminar aims to tackle this issue by introducing new mathematical framework to guide experimental design and data analysis. First, a quantitative experimental design method is developed to identify the optimal conditions for specific experimentation under realistic constraints of the diagnostic tools. By maximizing the expected prior-posterior information gain regarding key parameters of the fluid and kinetic models to be determined, the current work goes beyond conventional trial-and-error approaches and explores a pathway towards smart, efficient and automatic design of experiments and analysis of laser diagnostic data. Second, a new data analysis scheme is developed to aid imaging diagnostics of reacting flows, by enabling automatic harmonic extraction and phase-averaging of time-varying scalar fields. Example application of this scheme to the measurements of self-excited instabilities in premixed swirl flames has demonstrated its good utility in studying unsteady combustion problems. Lastly, some perspectives will be given on future research opportunities regarding high-throughput, information-rich laser measurements with the help of advanced experimental design and intelligent data processing methods.

Speaker

Dr Shengkai Wang is an Assistant Professor of the Department of Mechanics and Engineering Science, College of Engineering at Peking University. He received his PhD at the Department of Mechanical Engineering, Stanford University in 2017. Dr Wang works at the interdisciplinary frontier of optical sciences, fluid mechanics and thermal engineering. He develops and applies precision laser diagnostic tools to study the fundamental physical and chemical processes in gasdynamics, aerothermodynamics and combustion kinetics. He is also exploring opportunities of advancing laser spectroscopy to other research areas, such as novel energy conversion strategies and atmospheric monitoring, to address emerging measurement needs unmet by conventional methods.