title: Plasma-enhanced mixing and flameholding in supersonic flow.
abstract: The results of experimental study of plasma-based mixing, ignition and flameholding in a supersonic model combustor are presented in the paper. The model combustor has a length of 600 mm and cross section of 72 mm width and 60 mm height. The fuel is directly injected into supersonic airflow (Mach number M=2, static pressure P(st)=160-250 Torr) through wall orifices. Two series of tests are focused on flameholding and mixing correspondingly. In the first series, the near-surface quasi-DC electrical discharge is generated by flush-mounted electrodes at electrical power deposition of W(pl)=3-24 kW. The scope includes parametric study of ignition and flame front dynamics, and comparison of three schemes of plasma generation: the first and the second layouts examine the location of plasma generators upstream and downstream from the fuel injectors. The third pattern follows a novel approach of combined mixing/ignition technique, where the electrical discharge distributes along the fuel jet. The last pattern demonstrates a significant advantage in terms of flameholding limit. In the second series of tests, a long discharge of submicrosecond duration is generated across the flow and along the fuel jet. A gasdynamic instability of thermal cavity developed after a deposition of high-power density in a thin plasma filament promotes the air-fuel mixing. The technique studied in this work has weighty potential for high-speed combustion applications, including cold start/restart of scramjet engines and support of transition regime in dual-mode scramjet and at off-design operation.
authors.affiliation: Joint Institute for High Temperatures, Russian Academy of Sciences, 125412 Moscow, Russia.
authors.forename: Alexander
authors.initials: A
authors.lastname: Firsov
authors.affiliation: Joint Institute for High Temperatures, Russian Academy of Sciences, 125412 Moscow, Russia.
authors.forename: Konstantin V
authors.initials: KV
authors.lastname: Savelkin
authors.affiliation: Joint Institute for High Temperatures, Russian Academy of Sciences, 125412 Moscow, Russia.
authors.forename: Dmitry A
authors.initials: DA
authors.lastname: Yarantsev
authors.affiliation: Joint Institute for High Temperatures, Russian Academy of Sciences, 125412 Moscow, Russia Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA leonov.1@nd.edu.
authors.forename: Sergey B
authors.initials: SB
authors.lastname: Leonov
keywords: injection-ignition module; mixing enhancement; plasma-assisted combustion; supersonic combustor