Principal Investigator: Cappelli, Mark A. Institution: Stanford University Proposal No: CBET-0853471
Combustion of new, complex fuels such as bio-fuels, low-grade fuels, and fuel blends places new demand on reliable ignition and flame stability for safe, clean, efficient operation. This research with characterize and seek to understand a new approach using pulsed nanosecond plasma discharges to ignite and sustain combustion of these complex fuels over a broad range of operating conditions. Nanosecond pulsed discharges efficiently transfer electrical energy into chemical potential energy, without energy wasted to thermal heating of the gases. This chemical potential energy should lead to effective combustion under conditions where combustion might otherwise not take place at all.
The research necessarily brings together plasma physics, combustion chemistry, and fluid mechanics. Specifically, the fundamental phenomena will be studied in three classical combustion configurations: diffusion flames, premixed flames, and complex flames (e.g., flames with significant swirling and/or flow recirculation). For diffusion flames, plasma-based flame-holding strategies are being explored for non-premixed jet flames in both coflow and crossflow conditions. Studies of premixed flames will focus on novel discharge-enhanced expansion of the lean flammability limit. Studies of complex flames involve sustaining combustion with plasma enhancement under conditions of strong convective flow recirculation, where the degree of mixing is strongly dependent on the imposed flow field. The intent is to understand the processes for a range of fuel types (pure fuels, fuel mixtures, nitrogen-containing fuel mixtures) in a way that is not specific to a particular combustor but rather makes it applicable to a very broad range of combustion processes.
The research will contribute to establishing a fundamental knowledge base of linked combustion and plasma systems that will ultimately advance the nations need for clean, safe energy. It will also educate graduate students, undergraduates, and high-school students in this multidisciplinary field, combining aspects of electronics, spectroscopy, high-powered lasers, fluid and plasma science, and combustion.