The Experimental Investigation of Corona Discharge Induced Wall Jet

Abstract

Corona discharge-induced wind is created when high-voltages applied across sharp electrodes and larger-radius ground electrode. This study examines the characteristics of the electrohydrodynamic wall jet driven by corona discharge in the surface boundary layer. The experimental setup includes a sawtooth electrode with peaks spaced 5mm apart, with distance from the tip to the ground varying from 9 to 18mm in 3mm increments. Voltage was then applied across the system from 5kV to 18kV in 1kV increments. Two corona regimes, glow and streaming discharge, generated the ionic wind. Experiments show spanwise and vertical similar velocity profiles for both regimes. The shallow cavity at the anode tip aids ionization, which results in a stable ionic wind generation. Velocity is correlated with electrical current in the system. The corona transitions from the glow to the streaming regime was observed when the conductance of the system was greater than 0.004mA/V. The efficiency in converting electrical energy to mechanical wind energy increases as the voltage is increased while in the glow regime, to a maximum of 2.5% at 10kV, 15mm electrode separation. Transitioning to streaming discharge the efficiency dropped due to rapid increase in current while only modest increase in momentum injection.