Flow reversal in millimetric annular DBD plasma actuator
Flow reversal in millimetric annular DBD plasma actuator
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DOI：
10.1088/1361-6463/ac0145
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Huw Borradaile;Konstantinos Kourtzanidis;F. Rogier;K. Choi;X. Mao
中科院分区：
文献类型：
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作者：
Huw Borradaile;Konstantinos Kourtzanidis;F. Rogier;K. Choi;X. Mao
使用四种等离子体流体模型来研究当毫米环形介质阻挡放电 (DBD) 等离子体致动器的直径减小时发生的先前无法解释的流向反转。我们发现，从强向外射流到弱向内射流的转变是由正子循环期间负径向电流体动力强迫分量的不成比例减少引起的。这种作用力的变化是由于电场线曲率的增加造成的，这导致电介质充电速率更高，从而导致间歇性放电结构越来越多。通过类似的放电机制，流动反转还取决于电极的厚度和环境氧含量。这项研究表明，在毫/微米级流量控制问题中使用 DBD 等离子体执行器时，更薄的电极或更高的氧含量是有利的，因为它可以以更小的直径和更高的效率保持强大的向外射流。
A four-species plasma-fluid model is used to investigate the previously unexplained reversal of flow direction that occurs when the diameter of millimetric annular dielectric barrier discharge (DBD) plasma actuators reduces. We found that the transformation from a strong outward jet to a weak inward one is induced by disproportionate reduction of the negative radial electrohydrodynamic forcing component during the positive sub-cycle. This change of forcing is due to the increased curvature of the electric field lines, which leads to a higher rate of dielectric charging and thus an increasingly intermittent discharge structure. The flow reversal also depends on the thickness of the electrode and the ambient oxygen content via similar discharging mechanisms. This study indicates that a thinner electrode or higher oxygen fraction is favorable when using DBD plasma actuators in milli/microscale flow control problems since it maintains the strong outward jet at smaller diameter and with higher efficiency.