Evaporation rates of pure hydrocarbon liquids under the influences of natural convection and diffusion

Evaporation of liquid hydrocarbons was studied in order to better understand the relative influences of diffusion and buoyancy-induced convection of the vapors on the evaporation rate. Evaporation rates were measured using a simple gravimetric technique and the behavior of the vapor layer that quickly forms above the film was observed using schlieren imaging. Even for conditions for which the influence of buoyancy is strong, the evaporation rates are well correlated by a one-dimensional diffusion model if an effective vapor layer thickness is used.