Pressure distribution induced by ionic wind in needle-to-water corona discharge

The negative DC corona discharge in air at atmospheric pressure was investigated in a needle-to-water system to obtain the pressure distribution of corona ionic wind. The deformation of water surface was measured and the distribution of wind pressure over the water surface was calculated. The effects of varying discharge parameters, such as applied voltage, gap spacing, tip radius of needle, and the shape of grounded electrode, on the wind pressure were studied. The measured wind pressure ranges from several Pa to several tens of Pa and up to 33 Pa over a small area; the pressure is comparatively large in the center and decreases quickly outwards. In the experiment system, a higher voltage on a 3 mm gap resulted in a stronger pressure of the ionic wind; around the onset voltage, using a needle with tip radius of 50 μm obtained a larger wind pressure than using a needle with 100 μm tip radius, but the latter one can produce larger pressure at higher voltages. Plus, the shape of the grounded electrode only influences the wind pressure a little.