RESIDENCE TIME OF EMULSION DROPS ON AN INCLINED SURFACE ABOVE LEIDENFROST TEMPERATURE

The paper investigates the impact of single drops of water, Jatropha biodiesel (JBD), and their emulsions of varying composition on an inclined surface to clarify the influence of emulsification and impact velocity on the residence time (TR) above Leidenfrost temperature (TL). Results show that though the impact is inclined, the process solely depends on the normal component of the impact inertia. The residence time is found to depend on the properties and composition of the liquid. TR decreases with the increase in the percentage of water in the emulsion. TR is minimum for water and maximum for JBD. Water and JBD drops show disintegration during rebound, while disintegration does not occur for the emulsions. The reason is found to be the lower viscous dissipation for water and JBD drops, while higher dissipation for the emulsions suppresses the disintegration. TR shows no significant dependence on the impact velocity for a given composition. The tangential component of the velocity causes the sliding of the drop along the surface. TR is directly related to the total sliding distance (ST) of the drop over the surface. ST decreases with the increase in the percentage of water in the emulsion, similar to TR. ST increases with an increase in the impact velocity for a given liquid, as the sliding velocity increases due to the increase in the inertial energy of the drop.