The Effect of the Surface Inclination on the Hydrodynamics and Thermodynamics of Leidenfrost Droplets

Abstract

In this research, the effect of the surface inclination on the hydrodynamics and heat transfer of droplets impinging on very hot surfaces is studied. The applied numerical algorithm is based on the accurate calculation of the vaporization rate in the simulation process using a combination of the level set and ghost fluid methods. Also a mesh clustering technique is utilized to create sufficient mesh resolution near the surface in order to take into account the effect of the thin vapor layer between droplet and very hot surface. The results are verified against available experiments. The effect of the surface inclination on the droplet maximum spreading radius, droplet contact time and total heat removal from the surface is considered. Results show that for the studied regime, the maximum spreading radius of the droplet is decreased with an increase in the surface inclination while the droplet contact time on the surface is independent from the surface inclination. For inclinations greater than 45, the total heat removal is decreased considerably with an increase in the inclination angle. For smaller inclinations, the dependency of the total heat removal on the surface inclination is not strong.

Magnetofluidic mixing of a ferrofluid droplet under the influence of a time-dependent external field

“…The paradigm of droplet-based micromixing can be classified into two different types, namely open surface, and closed surface micromixing. Open surface droplet-based micromixing offers a few advantages over the closed surface microfluidic environment, such as simple fabrication, interfacial convenience, and free of any blockage such as bubble clogging (Greenspan 1978;Lin et al 2017;Long et al 2009;Pournaderi & Pishevar 2014;Smith 1995;Tam et al 2009). It may be mentioned here that droplet-based mixing in the open surface microfluidic platform can be accomplished by using two approaches viz., passive approach, and active approach.…”