Hanging a droplet with minimized intervention

Single droplet drying (SDD) by glass filament apparatus is a powerful tool for tracking droplet drying kinetics. However, the level and influence of intrusion of glass suspender into droplet have not been fully elucidated. In this work, the hanging processes of droplets by suspenders are numerically simulated by the volume of fluid (VOF) method, aimed at improved design of suspenders that can offer reduced suspender-droplet contact and increased droplet sphericity. Furthermore, the hanging simulation has been extended to small-sized droplets similar to those in spray drying operation which are too small to be addressed by the existing SDD technique. A comparison diagram of droplet suspension states at two scales has been constructed, which provides different suspension states of droplets as determined by the size of the suspender and the contact angle. The quantitative results can guide the design of minimal-intervention suspenders for droplets with specific properties.