Figure 5
From: Size distributions of droplets produced by ultrasonic nebulizers
Rescaled droplet size (d) distributions for the three different nebulizers, each of which measured three consecutive times. Solid lines are fits to a two-parameter compound Gamma distribution \({{\mathscr{P}}}_{m,n}\), Eq. (3). (a) Size distribution of the SAWN for the smallest droplets, with fit parameters \(m=3\) and \(n=4\). The fit parameters indicate a very large spread in pinch-off ligament sizes and very corrugated ligaments, which can be expected for the nebulization of a droplet by the violent mechanism as seen in Fig. 4a and illustrated in Fig. 1c. Median droplet size for the smallest droplets of the SAWN is 1.1 μm. (b) Size distribution for the mist maker with fit parameters \(m=40\) and \(n=8\) and a median droplet size of 5.6 μm. These parameters indicate that the wavelengths are very similar and the pinch-off ligaments reasonably smooth, in accordance with the capillary wave mechanism of a free surface such as present in case of the the mist maker. (c) Size distribution of the nebulizer chip, with \(m=20\) and \(n=8\) and a median droplet size of 9.5 μm. This shows that the nebulizer chip also has similar-sized pinch-off ligaments, although less so than the mist maker.
