Ionic wind produced by a millimeter-gap DC corona discharge ignited between a plate and an inclined needle
Eric Moreau*, Sonia Souakri, Romain Bellanger, Nicolas Benard
* The author to whom correspondence should be addressed.
University of Poitiers, PPRIME Institute (CNRS, ISAE-ENSMA), Teleport2, BP30179, 86962 Futuroscope, France
Abstract
This study aims at characterizing the ionic wind produced by a DC corona discharge ignited between a high voltage needle and a grounded plate electrode. The influence of several input parameters is investigated: the value and polarity of the applied voltage, the electrode gap (2.5 and 5 mm) and the angle between the plate and the needle (30°, 45° and 90°). The main results are as follows: (a) the positive corona discharge generates a higher ionic wind velocity compared to the negative one but a smaller flow rate because the produced jet is thinner, (b) the topology of the produced jet flow depends on the value and the polarity of the applied voltage, and it is linked to the discharge regime, (c) when the needle is perpendicular to the plate, the ionic wind jet impacts the plate in front of the needle, (d) when the needle is inclined, the angle of the ionic wind jet is weakly higher than the one of the needle, (e) in fact, the ionic wind jet follows the electric field lines close to the tip but it is deviated from its initial trajectory when one moves away from the tip, (f) downstream of the location at which the main jet impacts the plate wall, the ionic wind direction becomes parallel to the wall, (g) the velocity of this wall jet is maximum when we used a positive voltage, and the smallest gap and needle angle (2.5 mm and 30°, respectively in this study), (h) we can expect to enhance the wall jet performance by decreasing these both values in the future and that is encouraging to perfect new types of plasma actuators for applications such as airflow control or thermal exchange enhancement.
Keywords - Corona discharge, inclined needle, ionic wind, electrohydrodynamics, wall jet.
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