Tackling the challenges of OH-Laser Induced Fluorescence technique on detonation: numerical approach to improve experimental design


Project Description

Context: Compared to classical constant volume or constant pressure thermodynamic cycles, the detonation regime of combustion could increase by 40% the efficiency of engines. In line with the Paris agreement, identifying more efficient combustion processes is one of the strategies to limit CO2 emissions that contribute to climate change. In parallel to its promising application to the energy production field, detonation studies have also regained interest for safety applications, due to the last nuclear accident in Fukushima. Thus, two aspects can be distinguished: for transportation, researchers are focused on obtaining and controlling a self-sustained detonation in a specific engine (PDE or RDE), while for industrial safety, researchers are focused on identifying the detonation limits and the quenching mechanism of detonation to prevent them. While the measurement of temperature and chemical species is of current practice in conventional combustion process (flames, engines, etc…), the experimental characterization of detonation relies on the determination of the detonation velocity, global pressure, and density gradient structure. These information are limited to validate numerical simulations and to be confident in the phenomenological comprehension extracted from it. While planar laser-induced fluorescence of hydroxyl radical (OH-PLIF) is a powerful technique to characterize reaction fronts, previous studies have shown significant limitations of this technique for detonation visualization. Not only restricted to reaction front visualization, this technique is also of interest as it can give access to 2-D temperature measurements in detonations
Program - Mechanical Engineering
Division - Physical Sciences and Engineering
Center Affiliation - Clean Combustion Research Center
Field of Study - Mechanical engineering, chemical engineering, aerospace engineering

About the

Deanna Lacoste

Associate Professor, Mechanical Engineering

Deanna Lacoste

Professor Lacoste‘s research
interests are in plasma-assisted combustion and flame dynamics, with special
emphasis on control of thermoacoustic instabilities by non-equilibrium plasma
discharges. She is also interested in detonation and development of optical
diagnostics for combustion and electrical discharges.

Desired Project Deliverables

​First, the student will have to become familiar with the principle of the OH-PLIF technique and the particularities associated with its usage on detonations, which has high pressure and temperature variations, high-speed flow (up to 2000m/s), etc… Second, the sensitivity analysis of the fluorescence signal will be conducted to identify the most sensitive parameters of the PLIF signal. Third, optimal operating conditions (≠ maximizing the fluorescence signal) will be identified and tested experimentally. Due to both the strong non-linearities between the PLIF signal intensity and each parameter involved, machine-learning approaches may be used to facilitate the identification of the optimal operating conditions​