Control of Volumetric Ignition and Thermal-Chemical Instability in Weakly Ionized Plasma for High Pressure Ultra-lean Combustion

点击翻译按钮获取中文摘要

Advanced fuel-lean combustion engine technologies can increase the energy efficiency and reduce the carbon emissions. However, the development of this technology is hindered by the ignition failure in fuel-lean mixtures. To achieve successful ignition in fuel-lean mixtures, understanding of the mechanism of plasma reaction and propagation in engines is critical. However, the coupling between fuel chemistry and plasma-associated reactions in a combustible mixture has not been studied in detail. In this investigation, a collaborative team will develop new theoretical, computational, and experimental models to understand the fundamental mechanism of thermal-chemical processes occurring in combustible mixtures. If successful, the proposed investigation will provide a new well-validated theoretical model to simulate plasma-driven reactions in an engine, especially under ultra-lean fueling conditions with reduced carbon and pollutant emissions. The plasma model developed can also contribute to advancing other research topics, such as fuel reforming and materials synthesis. The research will also provide career development opportunity for graduate and undergraduate students in plasma sciences, combustion, sustainable energy, and laser imaging, and augment the Sustainable Energy certificate program for Princeton undergraduate studentsThe proposed study will develop: (1) a new thermal-chemical instability model to understand the mechanism of kinetic coupling between plasma and n-pentane combustion chemistry in plasma contraction, (2) advanced laser diagnostic methods to characterize the dynamics and chemical process of plasma instability in a combustible mixture at elevated pressure, (3) a validated three-dimensional computational model to simulate thermal-chemical instability of weakly ionized plasma in a combustion mixture, and (4) a novel volumetric ignition technique by controlling plasma instability using an energy cascading discharge array for ultra-lean ignition. The resulting new thermal-chemical instability model will significantly advance the understanding of the kinetic impact of plasma-combustion chemistry on plasma instability in engines. The experimental data of electron temperature, number density, and electric field will provide critical validation targets for the theory and numerical models. The novel volumetric ignition technique by using an instability controlled energy cascading discharge array will provide an innovative method for efficient ignition at fuel lean conditions.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.