Abstract
We conducted an experimental study of effects of dispersed oil droplet diameter on micro-explosion of oil-in-water (O/W) emulsion droplet during spheroid-type evaporation on a heated surface. The base fuel was n-dodecane, the surfactant was polyoxyethylene (6) lauryl ether. O/W emulsion was made with Shirasu Porous Glass (SPG) membrane, which is hydrophilic and has numerous and continuous pores, and then degassed. Also, the emulsion was stirred at low speed during the experiment. The hot surface temperature was 700 K, the initial droplet diameter was 1.95 mm, and the water content was 0.4. The pore diameter of the membrane was varied from 5 μm to 50 μm. The experiment of dropping the emulsion was conducted more than 30 times for each condition. The particle size distribution showed that the dispersed oil droplet diameter and its Sauter mean diameter decreased with the decrease of the membrane’s pore diameter. And as the pore diameter became smaller, the start time of phase separation was delayed. Total waiting time for disruptive microexplosion and its Weibull average increased with the decrease of the pore diameter. These results are considered to be due to the delay in the start time of phase separation as the dispersed oil droplet diameter decreases.
