Enhancement of evaporation rate by applying electric field (electrohydrodynamics) has been experimentally evaluated in this study. Corona wind produced by a fine wire electrode which is charged with positive or negative high DC voltage is directed towards the water surface which disturbs the saturated boundary layer over the surface and leads to substantial evaporation enhancement. In this study eight different air flow velocities (i.e. 0.125, 0.25, 0.5, 0.75, 1.0, 1.25, 1.5 and 1.75 m/s), four electrode spacings (i.e. 3, 4, 5 and 6 cm) and two different electrode radii (i.e. 77 and 295 µm) were used. Two sets of experiments, i.e. with and without electric field, have been conducted. Data obtained from the first experiment were used as reference for evaluation of evaporation enhancement at the presence of electric field. Applied voltages ranged from corona threshold voltage to spark over voltage at 1 kV increments. The results showed that corona wind has a great effect on water evaporation enhancement with very small amount of electric power usage, but its performance gradually diminishes by increasing the cross flow air velocity. Maximum enhancements were 7.3 and 3.6 for air velocities of 0.125 and 1.75 m/s, respectively. Although applying a wire electrode with higher radii of curvature results in less evaporation enhancement, its performance is higher than a thinner electrode. Applying positive corona leads to both, higher evaporation enhancement and higher performance, especially at higher electrode spacings. Moreover, two correlations have been introduced for evaluating of EHD evaporation enhancement value and its performance at the presence of axial air velocity over 0.75 m/s.
