Numerical investigation on water evaporation characteristics at low pressures in a stainless steel funnel

Abstract

In order to understand the effects of the flow in liquid phase and the temperature jump at liquid-vapor interface on the energy transport mechanism during evaporation process, a mathematical model describing the coupling of mass, momentum, and energy transfers with the interface evaporation is established. A series of numerical simulations are performed on the water evaporation in the funnel at low pressures ranging from 160 Pa to 776.1 Pa. Based on the simulation results, the flow pattern and temperature field are determined to analyze the formation reason of uniform temperature layer. Besides, the energy transfer mechanism in the evaporation process is revealed. The results show that the strong mixing action of the thermocapillary convection and the vertical flow results in the formation of uniform temperature layer. Evaporation mass flux and average temperature of the interface are closely related to the temperature jump. Liquid phase supplies almost all the energy demanded for the evaporation. The effect of buoyancy convection on heat transport should be considered at low pressure. Thermocapillary convection is a significant factor of the energy transport in the uniform temperature layer, and it cooperates with thermal conduction to provide energy to maintain the evaporation process.