Plasma actuation effect on a NACA 4412 airfoil

Purpose This paper aims to investigate the effects of a dielectric barrier discharge (DBD) plasma actuator (PA) qualitatively on aerodynamic characteristics of a 3 D-printed NACA 4412 airfoil model. Design/methodology/approach Airflow visualization study was performed at a Reynolds number of 35,000 in a small-scale open-loop wind tunnel. The effect of plasma actuation on flow separation was compared for the DBD PA with four different electrode configurations at 10°, 20° and 30° angles of attack. Findings Plasma activation may delay the onset of flow separation up to 6° and decreases the boundary layer thickness. The effects of plasma diminish as the angle of attack increases. Streamwise electrode configuration, in which electric wind is produced in a direction perpendicular to the freestream, is more effective in the reattachment of the airflow compared to the spanwise electrode configuration, in which the electric wind and the free stream are in the same direction. Practical implications The Reynolds number is much smaller than that in cruise aircraft conditions; however, the results are promising for low-velocity subsonic airflows such as improving control capabilities of unmanned aerial vehicles. Originality/value Superior efficacy of spanwise-generated electric wind over streamwise-generated one is demonstrated at a very low Reynolds number. The results in the plasma aerodynamics literature can be reproduced using ultra-low-cost off-the-shelf components. This is important because high voltage power amplifiers that are frequently encountered in the literature may be prohibitively expensive especially for resource-limited university aerodynamics laboratories.

Methods for calculating thermal processes under conditions of natural convection of gaseous methane under the influence of electrostatic fields

Relying on the review and analysis of scientific and technical literature, as well as the results of experimental studies, we developed new methods for calculating thermal processes occurring in gaseous methane during its natural convection, under the influence of electrostatic fields. In this study we show methods for calculating and determining the coefficients of heat transfer to gaseous methane under the influence of electric wind, as well as methods for calculating and determining the effect of electrostatic fields on the negative process of sedimentation on a heated experimental working plate in the volume of gaseous methane. A general method has been developed for the effective and safe application of electrostatic fields in gaseous methane, which must be carried out in the calculations, design, creation, and operation of new engines, power plants, and techno systems for single and reusable ground, air, aerospace and space-based aircraft.

Mathematical modeling of a submerged jet of electric wind

Technological processes of electro-gas dynamics of dispersed systems are based on charging and transporting dispersed raw material particles in a strong electric field of a corona discharge. It is accompanied by turbulent gas motion caused by momentum transfer of ions to gas molecules. This accompanying motion is called electric wind. It must be considered when calculating the trajectories of particles and devices design. In recent years, equipment is being developed, the operation of which is based on the direct use of electric wind. In most cases these studies are based on experimental research and empirical calculation formulas, therefore, to make the design and construction of this equipment science oriented, it is necessary to develop mathematical models and methods for calculating this phenomenon. The object of the research is a unipolar electric corona discharge of direct current between a negative corona wire and a flat electrode in the form of a mesh. The calculation of a turbulent jet of an electric wind is considered both within the framework of the boundary layer theory and in a full-scale formulation using the k- и k- turbulence models in the Comsol program. Two new solutions for the velocity field of a submerged flat jet of electric wind are found and compared. They are an analytical solution based on the boundary layer theory and a numerical solution in a full-scale formulation based on the Reynolds equation integration. The novelty of the solutions is that they are applied for a two-dimensional problem and consider the turbulent motion of gas. The phenomenon of electric wind is widely applied in modern technologies that allow electric and gas cleaning, disinfection, and water purification from organic impurities, as well as treatment and disinfection of surfaces and air which is especially important recently. In the case of jet spread of electric wind in a closed channel, the boundary layer approximation conditions are satisfied, and a self-similar solution can be used. In the case of an open jet, the calculation should be carried out in a full-scale formulation of the problem based on the numerical solution of the Reynolds equation.

EVALUATION OF THE INFLUENCE OF ELECTRIC WIND ON THE EFFICIENCY OF DISPERSED PARTICLES REMOVAL FROM THE FLUE GAS STREAM IN ELECTROSTATIC PRECIPITATORS

The question of influence of the electric wind on efficiency of dispersed particles removal from a flue gas stream in electrostatic filters has not been studied well enough. Estimates are given of the role and influence of electric wind on the particle trapping processes in industrial electrostatic precipitators, as well as the results of experiments and calculations using aplied computational fluid dynamics packages. The results of mathematical modeling of the speed of dust particles of different diameters under the action of electric wind in the inter-electrode space of a corona discharge are presented; and the effects of turbulence of a gas flow on the particles capturing, the influence of the near-wall jet and the probabilistic nature of the removal of solid particles from the dusted exhaust gas flow are evaluated. Ref. 18, Fig. 5.