Fundamental Study on Electrostatic Atomization of Biofuel/Water Emulsion = Fundamental Study on Electrostatic Atomization of Biofuel/Water Emulsion

다국어 초록 (Multilingual Abstract)

This paper reports the experimental investigation of electrostatic atomization of BDF/water emulsion. Biofuel, such as Bio Diesel Fuel (BDF), is expected as the alternate fuel because of its carbon-neutral characteristics. In the process of making the biofuels, biofuels include water and the separation energy cost is relatively high. From this viewpoint, it is expected that the water in the biofuel is utilized in a positive manner. Biofuel and water mixture usually have large electric conductivity in comparison with hydrocarbons and it is possible to control of atomization using the electrostatic energy. In addition, if the droplets and spray are charged, the spray shape and flame pattern could be controlled to enhance the combustion and to reduce the heat loss to the wall. From this background, the paper mainly is focused on the electrostatic atomization of the BDF/water mixture. For the comparison, n-hexadecane is used as a reference fuel. The mixture fraction of water is the parameter of the fuel. To keep the stable mixture, surface active agent was added in the tested fuels. The viscosity of some tested fuel was high and the characteristics of non-Newtonian viscosity were researched prior to atomization experiments. The thin capillary to inject the fuel and wire netting over the capillary are used as electrodes and direct current voltages are applied to the electrodes. The fuel is pushed by the pressurized nitrogen and injected to the air through the capillary. As the results, fraction of water affects the onset of mode change, such as dripping, spindle, cone-jet etc. Droplets diameters and droplets velocity were measured from the video images and the electric charge distribution was discussed to understand the electrostatic atomization.