Repetitively Pulsed Nonequilibrium Plasmas for Magnetohydrodynamic Flow Control and Plasma-Assisted Combustion

Abstract

This paper demonstrates significant potential of the use of high-voltage, nanosecond pulse duration, high pulse repetition rate discharges for aerospace applications. The present results demonstrate key advantages of these discharges: 1) stability at high pressures, high flow Mach numbers, and high-energy loadings by the sustainer discharge, 2) high-energy fractions going to ionization and molecular dissociation, and 3) targeted energy addition capability provided by independent control of the reduced electric field of the direct current sustainer discharge. These unique capabilities make possible the generation of stable, volume-filling, low-temperature plasmas and their use for high-speed flow control, nonthermal flow ignition, and gasdynamic lasers. In particular, the crossed pulsersustainer discharge was used for magnetohydrodynamic flow control in cold M 3 flows, providing first evidence of cold supersonic flow deceleration by Lorentz force. The pulsed discharge (without sustainer) was used to produce plasma chemical fuel oxidation, ignition, and flameholding in premixed hydrocarbon-air flows, in a wide range of equivalence ratios and flow velocities and at low plasma temperatures, 150-300 C. Finally, the pulser-sustainer discharge was used to generate singlet oxygen in an electric discharge excited oxygen-iodine laser. Laser gain and output power are measured in the M 3 supersonic cavity.

Picosecond CARS Measurements of Nitrogen Vibrational Loading and Rotational/Translational Temperature in Nonequilibrium Discharges

“…There is an increasing recent interest in the study of nanosecond pulsed non-equilibrium molecular plasmas due to their utility for a wide variety of potential applications such as plasma assisted combustion (Startkovskii 2005, Starikovskaya 2006, Adamovich 2009), electric discharge laser development (Adamovich 2008), and plasma flow control (Roupassov 2009, Little 2012, Nishihara 2011. Despite this utility, fundamental questions remain concerning the relative partitioning of plasma power into translation energy, molecular dissociation, and internal energy states, both electronic and vibrational, as well the importance and rates of key processes dominating heavy species thermalization subsequent to plasma decay.…”

Thomson Scattering Studies in He and He/H2 Nanosecond Pulse Nonequilibrium Plasmas

“…This type of discharge is used for several emerging applications, including electric discharge excited laser development [Adamovich 2008], high-speed plasma flow control [Roupassov 2009, Little 2012, Nishihara 2011, and plasma assisted combustion [Starikovskaya 2006, Adamovich 2008, Starikovskii 2013. In spite of a wide use of these discharges, underlying fundamental understanding of electron kinetics in nanosecond pulse plasmas remains far from understood.…”

Numerical Simulation of a Nanosecond-Pulse Discharge in Mach 5 Flow

“…In both formulations, stability was enforced using the minmod limiter in the MUSCL formalism. 58 The Poisson equation (10) was solved at the end of each subiteration in the implicit time-marching scheme. (This procedure yields a stable time step that is comparable to that obtained using methods based on the linearization of the right-hand-side of the Poisson equation.…”

“…1-3 Such discharges are efficient generators of both ions and electronically excited species because of their high instantaneous reduced electric field. 4 In aerospace applications, nanosecond-pulse discharges have been employed as flow control actuators, 5-8 as a source of ionization for nonequilibrium magnetohydrodynamic devices, 9,10 and as a means for enhancing ignition and combustion. 11,12 The generation of shock waves by volumetric heat release in pulsed discharges was observed and explained in the 1970s in the context of gas laser technology.…”