2010/10/16 by Abhishek Saha, Erick Tijerino, Saha, Abhishek +5
Engineering · Physics and Astronomy · #Combustion and flame dynamics #Electrohydrodynamics and Fluid Dynamics #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Fluid Dynamics and Mixing #Microfluidic and Bio-sensing Technologies #Nanomaterials and Printing Technologies #physics.flu-dyn
paper · pdf · doi:10.48550/arxiv.1010.3364
arxiv created 2010/10/16 · openalex publication_date 2010/10/16 · arxiv updated 2010/10/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Vaporization of liquid droplets containing particles has been studied extensively for its applications in combustion, thermal coating, ink-jet printing, spray cooling, drug delivery, and surface patterning. Droplets containing solid particles show a preferential solute-migration during drying process. Recently we carried out experiments with vaporizing droplet suspended in an acoustic levitator. In this work, we present detailed study of a laser irradiated droplet containing nanosilica particles. Infrared and High speed imaging of the heating process for different concentrations of nanosilica revealed an interesting solute migration pattern. Further investigation with Particle Image Velocimetry shows presence of strong recirculation within the levitated droplet. It also reveals that with increasing viscosity of the liquid the strength of this recirculation decreases. Due to the droplets rotation about the levitator axis, a centrifugal force also dominated the flow field within the droplet. High speed imaging shows that initial stage of heating is dominated by sharper diameter reduction. At the end of this stage the droplet takes a bowl shape. Next stage, which is termed as structure formation shows different characteristics for higher and lower concentrations. For nanosilica concentration of less than 1.3%, the bowl shape remains unaltered with further heating. On the other hand, for concentration greater than 1.9%, due to stronger centrifugal effect than recirculation, the particles migrate towards the equator plane creating horizontal ring structure. The horizontal ring very soon starts oscillating about the levitator axis. This creates an imbalance of forces resulting in reorientation of the ring. Thus a vertical ring is created.