Role of Excited Species in Plasma Enhanced Combustion

Drexel University, Philadelphia PA

Investigators

Abstract

CBET-0755632 Miller The goal of this research is to identify the fundamental mechanisms by which non-equilibrium plasmas promote combustion. The specific focus is on examining excited species from a non-equilibrium plasma and their roles and energy efficiency in autoignition and flame stabilization. Effects of various species (atoms, radicals, excited molecules) will be studied separately in a carefully controlled environment by generating the active species in a corona discharge and then injecting them into a fuel-air mixture. Reaction progress will be determined using in-situ gas sampling and laser diagnostics. Recent publications have demonstrated the value of these low-temperature plasmas in promoting ignition and flame propagation of hydrocarbons. One intriguing observation is that autoignition and flames have occurred for temperatures and stoichiometries that are outside the normal flammability limits for the fuels tested. However, recent modeling work suggests that the increased radical concentration produced by plasmas is insufficient to produce this effect. Furthermore, existing studies have not been able to discriminate between the effect of ionic species or excited species in promoting combustion, and excited species have essentially been ignored in traditional hydrocarbon combustion studies. Finding the true mechanism is the key to effective flame ignition and stabilization not only above but also below the autoignition threshold. This research combines the low-temperature, pre-ignition expertise of the Combustion and Fuels Research Group at Drexel University and the plasma expertise of the A. J. Drexel Plasma Institute at Drexel University, strengthening the work scientifically and engaging students in the resulting multidisciplinary research activity. The project will also leverage and take advantage of existing programs at Drexel University for enhancing minority participation at the graduate and undergraduate level, such as IGERT (Integrative Graduate Education and Research Traineeship), Bridges to the Doctorate, GAANN (Graduate Assistantships in the Areas of National Need), GEM (Graduate Education for Minorities), AMP (Alliance for Minority Participation), and three REU site programs. Introducing combustion, plasma, energy efficiency, and emissions reduction to under-represented minority students will help them to explore and develop their career interest in these fields.