EAGER: Collaborative Research: A Novel Method for Laminar Burning Speed Measurement at Ultra High-Pressures

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The next generation of advanced combustion devices will operate under ultra-high pressure conditions in order to improve the combustion efficiency and reduce emission of pollutants. However, at such extreme conditions, flame tends to become unstable and experimental measurement of fundamental properties becomes challenging. The principal aim of this project is to provide a detailed time- and space-resolved measurements of the ignition process at high pressures. In addition, the measurement methodologies and developed computational models will have a broad and valuable impact on combustion and plasma communities by enabling predictive capabilities for designing and optimizing advanced combustion devices operating under extreme conditions. The project will also encompass significant educational activities, including classroom and community engagement, integration of research into relevant courses, undergraduate research program, and an outreach program for K-12 students.The main goal of this project is to develop a novel method to measure LBS in the ignition affected region using a spherically expanding flame under ultra-high pressures. The complication with this region is that, the kernel growth rate does not only depend on the chemical reaction but also on other terms such as energy discharge, as well as radiative and conductive energy losses. None of these terms has been adequately assessed, due to the generation of ionized gas (i.e., plasma). The proposed research will fill this broad knowledge gap via combined experimental and modeling studies focused in three specific aims: (1) using a well-defined and well-controlled high-pressure experimental configuration; (2) developing a self-consistent theoretical framework to explain the influence of energy discharge on the plasma formation and initial flame propagation; and (3) modifying an available high-fidelity direct numerical simulation (DNS) code to account for the evolution of the plasma kernel and the ignition process. On the experimental side, the project will utilize high-speed imaging of the plasma kernel propagation in conjunction with advanced laser diagnostics. The plasma properties will be calculated using statistical thermodynamics. This project, for the first time, aims to fundamentally understand the underlying physicochemical processes controlling the ultra-high pressure ignition in a high temporal and spatial resolution.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.