In this research, the maximum deformation ratio of water-based paint droplets impacting and spreading onto a flat solid surface was investigated numerically based on the Navier–Stokes equation coupled with the level set method. The effects of droplet size, impact velocity, and equilibrium contact angle are taken into account. The maximum deformation ratio increases as droplet size and impact ve...

Evaporating sessile drops remain pinned at the contact line during much of the evaporation process, and leave a ring of residue on the surface upon dryout. The intensive mass loss near the contact line causes solute particles to flow to the edge of the droplet and deposit at the contact line. The high vapor diffusion gradient and the low thermal resistance of the film near the contact line are ...

A hybrid axisymmetric conservative phase-field lattice Boltzmann method is applied to investigate the influence of Marangoni number ( Ma ), density ratio ρ r and radius R ) on thermocapillary migration a deformable hollow droplet with difference in variable fluid properties, where (radius) part droplet. The isotherms show that heat transfer around changed from conduction convection increase . H...

The retention and drainage of water on heat exchangers is extremely important in air-conditioning, refrigeration, and heat-pumping systems. In this work, droplets of varying sizes sliding on an inclined heat exchanger materials with and without a wettability gradient are observed using a high-speed camera. The dynamic contact angles, the shape evolution and the velocity of the droplet are obtai...

In recent years, there has been growing interest to use computational fluid dynamics (CFD) for exploring dropletparticles interaction under the turbulent flow of air inside spray dryer systems. The final goal is to predict the dried solid particle size and mass flux distributions under the conditions of collision, coalescence and agglomeration of the droplets and particles. The coarse-grained s...

This study investigates the local flow characteristics near droplet-droplet collisions by means of direct numerical simulation of isotropic cloudlike turbulence. The key finding is that, generally, droplets do not collide where they preferentially concentrate. Preferential concentration is found to happen as expected in regions of low enstrophy (vorticity magnitude), but collisions tend to take...

Since the early nineteenth century, it has been known that an electric potential can be generated by driving an ionic liquid through fine channels or holes under a pressure gradient. More recently, it has been reported that carbon nanotubes can generate a voltage when immersed in flowing liquids, but the exact origin of these observations is unclear, and generating electricity without a pressur...

We present an experimental study of a new regime of monodisperse micro–droplet generation that we named the balloon regime. A dispersion of oil in water in a T–junction microfluidic system was studied. Several microfluidic devices having different cross– sections of the continuous and the dispersed phases micro–channels were tested. This new regime appears only for low dispersed phase velocity....

Dropwise condensation processes, where condensation occurs through small droplets on a solid surface, has been demonstrated to significantly improve heat transfer rates in comparison to film-wise condensation (where a whole surface is covered by a thin film of liquid). Dropwise condensation usually takes place on superhydrophobic surfaces, and one of the main engineering and scientific challeng...