I. P. Zavershinskii

Structure of RF capacitive discharge in swirl airflow at atmospheric pressure

Conditions for the onset of transitions between corona and pinch types of one-electrode radiofrequency capacitive discharges in swirl airflow at atmospheric pressure have been analyzed. It is established that the transitions observed at various values of the gas flow rate and swirl parameter are related primarily to the gasdynamic structure of airflow. Calculated data obtained in the framework of a proposed theoretical model are qualitatively consistent with the available experimental data.

Numerical modeling of precessing vortex core in the presence of local heat sources

Based on the results of numerical simulation of a nonstationary, nonaxisymmetric turbulent swirling gas flow in a tube with local sources of heat release, it is shown that a precessing vortex core (PVC) appears at supercritical values of the swirl parameter as a result of the development of instability of a left-handed bending mode. The dependence of the PVC frequency on the mass flow rate of the gas and the heat-source power has been studied. As the heat-source power increases, the frequency of precession grows while the amplitude of vortex core oscillations drops.

Streamlining of a cylinder with an electric arc rotating in a magnetic field

Streamlining of a circular cylinder with a localized heat source modeling an MHD actuator in which the plasma arc channel moves along the cylinder surface under the action of the Lorentz force in a radial magnetic field is studied experimentally and simulated numerically. It is shown that the presence of a moving heat release region leads to a break in the symmetry in cylinder streamlining by the external flow and the appearance of a nonzero lift force and circulation.

Features of the transverse discharge glow depending on the gas flow rate in a vortex chamber

Experimentally observed features in the formation of glowing zones in gas discharge at various mass flow rates are qualitatively explained based on the numerical simulation of a turbulent swirling flow with a local source of heat release.

General nonlinear acoustical equation of relaxing media and its stationary solutions

During previous years, the conditions for the negative second (bulk) viscosity existence were found in a large number of nonequilibrium media. The media with negative viscosity possess a number of new properties including acoustical activity. In the present paper, we investigate the nonlinear stage of acoustical perturbation evolution in acoustically active nonequilibrium media using three models: the vibrationally excited gas with the exponential model of relaxation, the chemical active two component mixture with a nonequilibrium reaction and media with the general heat-loss function. The general nonlinear acoustical equation describing stationary density profiles behind the shock wave front in these media is obtained and solved. Its low- and high- frequency limits correspond to the Kuramoto-Sivashinsky equation and the Burgers equation with a source, respectively. Stationary structures of general equation, the conditions of their establishment and all their parameters are found analytically and numerica...

High effective heterogeneous plasma vortex reactor for production of heat energy and hydrogen

This work is a continuation of our previous studies [1-10] of physical parameters and properties of a long-lived heterogeneous plasmoid (plasma formation with erosive nanoclusters) created by combined discharge in a high-speed swirl flow. Here interaction of metal nanoclusters with hydrogen atoms is studied in a plasma vortex reactor (PVR) with argon-water steam mixture. Metal nanoclusters were created by nickel cathodes erosion at combined discharge on. Dissociated hydrogen atoms and ions were obtained in water steam by electric discharge. These hydrogen atoms and ions interacted with metal nanoclusters, which resulted in the creation of a stable plasmoid in a swirl gas flow. This plasmoid has been found to create intensive soft X-ray radiation. Plasma parameters of this plasmoid were measured by optical spectroscopy method. It has been obtained that there is a high non-equilibrium plasmoid: Te > TV >> TR. The measured coefficient of energy performance of this plasmoid is about COP = 2÷10. This extra power release in plasmoid is supposed to be connected with internal excited electrons. The obtained experimental results have proved our suggestion.

Numerical simulation of an argon swirling flow in the presence of a DC discharge

Numerical simulations of the non-stationary three-dimensional swirling Ar flow are presented for plasma vortex reactor (PVR) with a paraxial heat source at various positions of the heat source and electrode forms. Flow and duct parameters correspond to the experimental conditions. Flow velocity and thermal fields have been obtained.

Air flow control around a cylindrical model induced by a rotating electric arc discharge in an external magnetic field. Part II

The structure and dynamics of a near-wall gas flow produced by a rotating electric arc discharge in an external magnetic field around a cylindrical model without an incoming flow has been investigated. The electric arc on the model has been produced by a combined electric discharge (low-current rf discharge + high-current pulse-periodic discharge). Permanent magnets with induction B ≈ 0.1 T have been placed inside the cylindrical models. Ring electrodes are arranged on the surface of the model. The structure and dynamics of the near-wall gas flow around the cylindrical model have been investigated using high-speed photography, as well as the shadowgraph and particle image velocimetry (PIV) methods.

The stability of swirling flows with a heat source

The absolute instability of a Rankine vortex with an axial flow and paraxial heat source is investigated. The dispersion relation for vortex modes is derived analytically. The dependence of dispersion properties of the media on control parameters such as swirl parameter S, velocity a, and heat source power (density parameter Q) is studied. The frequency of helical waves increases and the increment decreases with increasing heat source power, accompanied by a decrease in the width of the neutral stability region. Numerical analysis also suggests that one of the dispersion curve branches could include an instability region of a parametric nature.

Evolution modeling of fast and slow magnetoacoustic waves in thermally unstable plasma

The nonlinear evolution of fast and slow magnetoacoustic waves in the plasma medium with non-adiabatic heating/cooling processes is under consideration. The magnetic field is assumed to be inclined at an arbitrary angle to the direction of wave propagation. The non-adiabatic processes depend on temperature and density and result in the steady non-equilibrium state of the medium. The steady state caused by the balance between heating and cooling rates makes it possible for thermal instabilities to appear. This research is focused on the wave mode of thermal instability (isentropic instability). The presence of other modes of the thermal instability is neglected. The isentropic instability influences on acoustic and magnetoacoustic waves and causes wave amplification. Linear analysis predicts simultaneous amplification of fast and slow magnetoacoustic waves with different increments. Furthermore, analysis predicts simultaneous disintegration of fast and slow waves on the sequences of autowave (self-sustaini...