Study of Induced EHD Flow by Microplasma Vortex Generator

Abstract

For flow control, plasma actuators have the advantages of no moving parts. An experimental study was carried out to generate vortexes using a microplasma actuator. Also, a 3-D numerical simulation code was developed to calculate the flow generated by the microplasma actuator. The numerical simulation used the Suzen–Huang model coupled with Navier–Stokes equations. Our microplasma actuator has a thin dielectric layer with a thickness of $25~\mu \text{m}$ between the grounded and high-voltage energized electrodes, which enables to drive our device at less than 1 kV. The high-voltage and grounded electrodes have both holes. In the series of experiments, an ac voltage with an amplitude 1 kV and a frequency of 20 kHz was applied to the electrode. The induced flow was visualized using an Nd: YVO4 532-nm laser, and the flow velocity was measured using the particle tracking velocimetry (PTV) method. Incense smoke was utilized as a tracer particle. The electrohydrodynamic (EHD) flow was induced around the holes of high-voltage electrode, thus vortexes appeared above these holes. In order to study the basic phenomena of the flow, one and four holes were isolated from the electrode; thus, the phenomena could be observed in a simplified version of the electrode. The 3-D numerical simulation code showed similar results both in values and flow configuration compared with the experimental results.