Air purification using mists generated by an efficient multi-fluid mixer

Sadatomi and Kawahara developed an efficient, i.e., energysaving- type, multi-fluid mixer, which can generate mists (or micro-bubbles) by introducing pressurized air (or water) alone because water (or air) as a source of mists (or micro-bubbles) are automatically sucked by a vacuum pressure arisen inside the mixer. In the present paper, firstly, the hydraulic performance of the mixer in mists generation case is introduced by referring to our previous papers. Secondly, various applications of mists, such as air cooling in greenhouses and pigsty, adsorptions of black smoke in the chimney of a boiler burning Refuse Paper & Plastic Fuel (RPF), and adsorption of carbon dioxide (CO2) in room are described. In the CO2 adsorption tests, mists were sprayed for five minutes by our multi-fluid mixer, commercial single-fluid and twin-fluid atomizers in turn in a test room, and time variations of CO2 concentration in air after the introduction of CO2 in the room were measured at the bottom of the room to compare the CO2 adsorption rates for the respective cases. In addition, diameters of droplets captured in a small oil pond were measured with a microscope. As a result, superiority of our multi-fluid mixer was confirmed, because 40% droplets were 20 to 40 m in diameter, and the CO2 adsorption rate by the mists with our multi-fluid mixer was 25 % larger than that with the commercial ones.Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016