Mohammad Hassan Rahimian

University of Tehran, School of Mechanical Engineering



The objective of this paper is to investigate numerical simulation of a liquid drop moving and evaporating on a hot surface. A two phase flow Lattice Boltzmann method which is presented by Lee and his co-worker is extended to capture phase change phenomenon. Incompressible and high density ratio is the most important properties of the Lee method. For phase change the divergence free condition of the velocity is not satisfied. Cahn-Hilliard equation is extended to capture droplet vaporization.  Heat equation is solved in by additional distribution function. Contact angle between solid, Liquid and gas is considered in this work. In simulating of water drop evaporation the drop will stick to the hot surface when the temperature is less then boiling temperature. While after boiling temperature the drop will move and dance on the hot surface. Weber and Froude number, evaporating rate, density and viscosity ratio, Prandtl number of gas and liquid and contact angle will affect the !

motion, deformation and evaporation of the drop. The drop increases in its moving and deforming by Increasing in its evaporating rate. Decreasing in Froude number will increase heat transfer to the drop and increase evaporating rate and will increase its motion.