Experimental study of falling film evaporation on a vertical plate

Abstract

In this paper, an experimental study is conducted on the evaporation of a film of water. The liquid film falls along the wall of a vertical plate and is exposed to a uniform heat flux density. We chose a metal plate with practical dimensions to obtain a system easy-to-use. We used a grid of 32 thermistors (NTC) to track the temperature evolution on the plate, which is heated uniformly and homogeneously by a silicone-coated copper heating plate. The system is insulated, and numerous precautions have been taken to avoid heat loss at the plate's edges and back to ensure complete heat transfer between the heating plate and the metal plate. The results show that the temperature is higher for systems with greater heat flux density q and a lower mass flow rate Γ0. It was found that the increase of imposed heat flux density q leads to an increase in the evaporation phenomenon; for example, with a heat flux density of 2200 W/m2, the system evaporation efficiency is 54 %, and 39 % for a mass flow rate of Γ0 = 2 Kg/h.m and Γ0 = 3 Kg/h.m respectively.