scholarly journals Thermal Fluctuation Characteristics around a Nanosecond Pulsed Dielectric Barrier Discharge Plasma Actuator using a Frequency Analysis based on Schlieren Images

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 628 ◽  
Author(s):  
Takahiro Ukai ◽  
Konstantinos Kontis
Keyword(s):  
Frequency Analysis ◽  
Discharge Plasma ◽  
Thermal Fluctuation ◽  
Plasma Discharge ◽  
Pulse Frequency ◽  
Dielectric Barrier Discharge Plasma ◽  
Burst Event ◽  
Maximum Fluctuation ◽  
Barrier Discharge Plasma ◽  
Schlieren Images

A thermal fluctuation driven by a burst plasma discharge is experimentally investigated using a frequency analysis based on the Schlieren images. The burst plasma discharge is controlled by an interval frequency fint = 200 Hz and a pulse frequency fB = 3.6 kHz as well as the duration time of the burst event: Ton. A burst feature is defined as a burst ratio BR = Ton/(1/fint). The burst plasma discharge generates a burst-induced hot plume growing above a ground electrode. In a high burst ratio, which is BR = 0.45 and 0.57, the burst-induced hot plume is formed as a wave thermal pattern that is mainly fluctuated at the interval frequency of 200 Hz. Additionally, a maximum fluctuation spot of 200 Hz appears near the edge of an exposed electrode in a low burst ratio, whereas it moves towards the ground electrode in the high burst ratio. The possible scenario is that a relatively strong ionic wind and/or an induced jet generated in the high burst ratio might cause the movement of the maximum fluctuation spot.

scholarly journals Improving water absorption time and the natural silk strength (Bombyx Mori) using atmospheric dielectric barrier discharge plasma

2021 ◽  
Vol 3 (2) ◽  
pp. 165-169
Author(s):  
Zaenul Muhlisin ◽  
Muhammad Adrian Lathif ◽  
Fajar Arianto ◽  
Pandji Triadyaksa
Keyword(s):  
Water Absorption ◽  
Discharge Plasma ◽  
Barrier Discharge ◽  
Plasma Discharge ◽  
Dielectric Barrier Discharge Plasma ◽  
Dielectric Barrier ◽  
Absorption Time ◽  
Natural Silk ◽  
Plane Electrode ◽  
Barrier Discharge Plasma

This researchaimed to obtain Dielectric Barrier Discharge plasma discharge characteristics with and without the placement of natural silkBombyx Mori on one of the electrodes. Furthermore, the strength and the water absorption time of the irradiated silk samples will be analyzed.  Plasma discharge is generated by connecting electrodes of point-to-plane configuration with a sheet of glass inserted on the plane electrode at atmospheric conditions. The characterization of plasma discharge, either with or without the natural silk samples' placement on the plane electrode, was performed by increasing A.C.'s high voltage power source to reach arch discharge. Theelectrode spacing varied from 0.7 cm to 2.5 cm with a 0.3 cm increment. Sample irradiation was performed using cold plasma for 5, 15, and 30 minutes respectively. Placing or not placing the natural silk samples on the plane electrode will increase the plasma's discharge current and increase the high voltage. Moreover, increasing the distance between the electrodes and placing the sample on the plane electrode decreases the discharge current. Using Scanning Electron Microscopy, it was found that increasing plasma irradiation time on samples decreases the silk thread'sdiameterand shortening its water absorption time. The strength of irradiated fabric was reduceduntil 15 minutes of irradiation. However, at 30 minutes of irradiation, there was an increase in sample thickness compared to control samples.

Impact of dielectric barrier discharge plasma on the wake of a wind turbine blade section oscillating in plunge

2021 ◽  
pp. 095765092110337
Author(s):  
GH Maleki ◽  
Ali R Davari ◽  
MR Soltani
Keyword(s):  
Wind Turbine ◽  
Dielectric Barrier Discharge ◽  
Turbine Blade ◽  
Discharge Plasma ◽  
Barrier Discharge ◽  
Wind Turbine Blade ◽  
Plasma Actuators ◽  
Dielectric Barrier Discharge Plasma ◽  
Dielectric Barrier ◽  
Barrier Discharge Plasma

Effects of dielectric barrier discharge plasma have been studied on the wake velocity profiles of a section of a 660 kW wind turbine blade in plunging motion in a wind tunnel. The corresponding unsteady velocity profiles show remarkable improvement when the plasma actuators were operating and the angles of attack of the model were beyond the static stall angles of the airfoil. As a result the drag force was considerably reduced. It is further observed that the plasma-induced flow attenuates the leading edge vortices that are periodically shed into wake and diminishes the large eddies downstream. The favorable effects of the plasma augmentation are shown to occur near the uppermost and lowermost positions of the plunging paths where the wake is primarily dominated by the vortices of the same sign. The wake structure in the presence of the flow induced by the plasma actuators shows that the actual effective angles of attack seen by the plunging airfoil reduces in comparison with that for the case of the plasma augmentation off situation.

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