Oxygen transfer and power consumption in an aeration system using mist and circulation flow generated by a rotating cone

Abstract

We have experimentally found the liquid film flow characteristics rising along the outer surface of a rotating cone. When the film flow goes up fully upward, the liquid film cannot keep the filmwise condition and is eventually atomized into a mist flow. In this research, we apply the mechanism to atomize the liquid and to transport oxygen from the air to the water through the atomized water droplets. It is recognized that the mixing is effective in oxygen mass transfer. It is found that a dual effect of the mixing and mist flow by using a rotating cone increases the oxygen mas7s transfer because the mist flow has a small diameter and large surface area between liquid and gas. In addition, the flow pattern is changed from steady flow to unsteady one if the rotation rate increases further, where the oxygen mass transfer is slightly enhanced. Furthermore, a correlation between the unit volume power consumption and the oxygen mass transfer is examined and shows that the oxygen transfer increases in power law relationship with the unit volume power consumption in the case with the mist flow.