Modeling evaporation using models that are not boundary-layer regulated

Abstract

Experimentation shows that oil is not strictly air boundary-layer regulated. The fact that oil evaporation is not strictly boundary-layer regulated implies that a simplistic evaporation equation suffices to describe the process. The following processes do not require consideration: wind velocity, turbulence level, area, thickness, and scale size. The factors important to evaporation are time and temperature. The equation parameters found experimentally for the evaporation of oils can be related to commonly available distillation data for the oil. Specifically, it has been found that the distillation percentage at 180 °C correlates well with the equation parameters. Relationships have been developed enabling calculation of evaporation equations directly from distillation data: (1) percentage evaporated =0.165(%D) ln(t) where % D is the percentage (by weight) distilled at 180 °C and t is the time in minutes. These equations were combined with the equations generated to account for the temperature variations: (2) percentage evaporated =[0.165(%D)+0.045(T−15)] ln(t) The results have application in oil spill prediction and modeling. The simple equations can be applied using readily available data such as sea temperature and time. Old equations required oil vapour pressure, specialized distillation data, spill area, wind speed, and mass transfer coefficients, all of which are difficult to obtain.