Mass Remaining During Evaporation of Sessile Drop

摘要

A theory to predict the evaporation rate of HD (mustard agent) for the special case of a glass substrate has been developed. This is an important reference case for the wind tunnel and field test measurements of the HD evaporation rate. The HD drop is treated as a spherical segment with a constant base diameter characterized by the variation of the droplet shape factor (height to base diameter) or contact angle. A combined variation of diameter and contact angle as a power law function is advanced with the effects of varying the power law exponent investigated. This theory is applied to experimental wind tunnel data; but due to the lack of initial shape factor measurements, appropriate values of shape factor and power law exponents are selected to achieve good agreement. A transformation is introduced that provides an effective method of correlating all the experimental data. The effects of unsteady atmospheric conditions on the mass remaining are due to nonlinearities, and they can be computed by introducing a transformed time.