Bubbles, drops and nucleation

A small liquid droplet is surrounded by pure vapor of the same material at the same temperature (e.g., a water droplet 

FIGURE 14.5 A small drop of liquid suspended in a vapor of the same chemical species. We ignore the very slow gravity settling of 

Example 14.6 Estimate the difference in pressure between inside and outside of a droplet of water suspended in steam at 100°C, with Foutside= 1 atm, for various drop diameters. 

The metric steam table [7, p. 267] (see Problem 14.22) gives the surface tension between steam and water at lOO C as 0.05892 N/m, so for a 1-mm drop 

FIGURE 14.6 Sketch for force balance around a small droplet, cut in half. The surface force, acting on the cut surface and the pressure force acting on the cut projected area are equal and opposite, leading to Eq. 14.16. (From de Nevers, N. Fluid Mechanics for Chemical Engineers, ed. 2. New York McGraw-Hill, p. 490 (1991). Reproduced by permission of the McGraw-Hill Companies.) 

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