Evaporation From Liquid Spillages: State of the Art and Improvements

Statistics show that leaks and liquid spillage are among the more frequent industrial hazards. In case of volatile compounds, evaporation represents a source term creating possibly flammable or toxic vapors. Evaporation is regulated by a mass and a heat transfer balances. Mass transfer was studied by several authors (Braun, Hummel, Chaîneaux, Kelly Zion, Raj and Morris, Mackay and Matsugu). The Mackay and Matsugu equation is widely used in consequences predictive tools. But what is the accuracy of this and other equations? How is solved the heat transfer balance? Some parameters such as wind velocity, soil composition and temperature are most often unknown when a spill occurs. What is the influence of a misevaluation of these parameters on evaporation prediction? The aim of this piece of work is to statute on accuracy and sensitivity of several significant works on a set of new experimental data collected in the laboratory, and to discuss on the influence of a wrong evaluation of the key parameters on evaporation. Experiments were performed on concrete in a wind channel. A large instrumentation was set up in order to characterize wind profile over the spillage, liquid temperature stratification, heat flux form the concrete, evaporation rate, solar heat flux, convective heat flux. These data allowed to (i) test mass transfer equations accuracy and sensitivity, (ii) test mass transfer balance accuracy, (iii) highlight points of interest such as influence of liquid temperature stratification, soil effects, wind profile over the liquid.