Vortex Control by Non-Equilibrium Plasma

Abstract

Nomenclature PVR= plasma vortex reactor HF = high frequency F HF = HF frequency F M = modulation frequency of HFD T i = pulse duration I = electric discharge current V = electric discharge voltage Q e = power input in plasma V x = axial flow velocity V t = tangential flow velocity P st = static pressure T g = gas temperature T R = rotation temperature T V = vibration temperature T e = electron excitation temperature T b = black body temperature Abstract Study of a longitudinal plasmoid in swirl flow is very important both for plasma aerodynamics and extra energy release 1-8, 10 . A longitudinal heterogeneous plasmoid structure and its dynamics in the swirl flow were studied in our previous works in detail 1-6 . The present work is a continuation of the previous ones. The non-equilibrium combined discharge (DC discharge + HF discharge) is used in this experimental work. A pulsed repetitive power pumping in the swirl flow is created by the combined discharge. The plasma created by this discharge can disturb the initial swirl flow. Plasma and airflow parameters are measured by different diagnostic instrumentation including a high-speed camera, electric and current probes, an optical spectrometer and etc. Following main new experimental and theoretical results are obtained in this work: a velocity distribution and a gas temperature distribution are measured in the swirl flow at different discharge and gas flow parameters. Detail optical spectra with a high resolution in a vortex longitudinal plasmoid created by the combined electric discharge are obtained. Processing of these spectra gives an important information about nonequilibrium processes inside the longitudinal plasmoid in the swirl flow. Obtained results are used in a theoretical model of plasma and a chemical kinetics in the vortex heterogeneous plasmoid created by the non-equilibrium DC discharge. Numerical results on a swirl flow structure and its evolution at plasma on are obtained and compared with experimental results.

Aerodynamic actuation characteristics of radio-frequency discharge plasma and control of supersonic flow

“…Compared with other discharge styles, RF discharge exhibits several advantages including high heating efficiency, strong discharge stability, and convenient power adjustment. [15,16] In particular, previous studies also confirmed the favorable thermal effect of RF-DBD. [17] All of these suggest that RF plasma has great potential in shock wave control.…”

“…In addition, the characteristic structure of the vortex cluster can be characterized by both magnitude and size. [15] Hence, it can be concluded that the vortex cluster in the boundary layer expands after the application of actuation.…”

Computational gas dynamics in a wide range of Mach number on heterogeneous cluster architecture

“…The second problem was used to calculate flow with M ∼ 0.2 and complex geometry. The results where benchmarked against PIV [9] measurements and gave good correlation with both time-steppers.…”

Thermal characterisation of dielectric barrier discharge plasma actuation driven by radio frequency voltage at low pressure

“…One promising plasma actuation type is radio frequency (RF) discharge plasma actuation, in which the applied voltage oscillates at frequencies of up to MHz to sustain the discharge primarily through electron diffusion, as investigated in [4, 5]. Apart from high heating efficiency, the RF discharge has the advantages of high stability in the high‐speed airflow and convenient power regulation, which has wide application prospect in flow control [6–8].…”