A theoretical and experimental study of the behavior of drops impacting onto a dry solid surface was conducted. For drop sizes and velocities typically encountered with high-pressure sprays, the impacting drop flattens or spreads and then undergoes dampened vibratory motion until it becomes quiescent. Assuming that the impacting drop forms a flat disk, a theoretical maximum dynamic spread factor is derived in terms of the weber number of the spray and a correction factor c denoting deviation from the simple model. The optimum dynamic spread factor, and the value of c, depends upon the drop size and velocity and the nature of the drop and target surface. For water sprays impacting a dry, lightly dust-laden surface of bituminous coal, the dynamic coverage is about 10 times the static coverage because of the drop flattening upon impact, that is, adequate dynamic coverage can be achieved without saturating the surface. In a lightly dust-laden surface, the impacting drops essentially completely scavenge the particles in the swept area.
I&ec Process Design and Development, V. 16, April 1977, PP. 192-197