Info

Figure 11. The change of average diameter of water droplets (Dw) prepared by

Membranes 1, 2 and 3 as a function of average diameter of Membranes

Where g is acceleration due to gravity, <5 is empirically derived correlation factor (1.65) (24), and p and p0 are density of droplet liquid and surrounding fluid, respectively. Supposing the theoretical diameter of a droplet as Dwt, the Eqn. (4) can be rewritten as the Eqn. (5).

The theoretical ratio of Dw was calculated for Membranes 1, 2 and 3 to be 1.0:1.4:1.7 by substituting the corresponding Dp for D in Eqn. (5) and by assuming p=l (water) and po=0.8625 (toluene) g/cm3. However, the actual ratio of Dw, prepared with 10 wt. % of PE-64 for example, for Membranes 1, 2 and 3 is 0.69:1.38:1.62 i.e., 1.0:2.0:2.4. This experimental size ratio is much larger than that of the theoretical one stated above. This discrepancy between the theoretical and experimental size ratios indicates that the Dp is not a factor determining the water droplet size. According to this experimental size ratio, the actual size ratio of the effective pore diameters of the SPG membranes on the formation of water droplets can be recalculated from the Eqn. (5) for Membranes 1, 2 and 3 as 1.0:8.0:13.8. Since the Dp of Membrane 1 is 0.98 nm which is close to unity, these values in the actual size ratio of the effective pore diameters of the SPG membranes can be regarded as [im unit. In other words, the effective pore diameters for Membranes 2 and 3 can be estimated to be 8.0 and 13.8 urn, respectively. These calculated effective pore diameters of Membranes 2 and 3, however, are much larger than the Dp of 2.70 and 4.70 |im of respective filter

0 0

Post a comment