Foam regime

Previous work with Oldershaw columns (209-211), however, spells a note of caution to Fair et al. s conclusion. For a fixed system, higher Oldershaw column efficiencies were measured under cellular foam conditions than under froth conditions. For this reason, Gerster (212) warned that when cellular foam can form, scaleup from an Oldershaw column may be dangerous. The conclusions presented by Fair et al. (208) do not extend to Oldershaw columns operating in the Cellular foam regime. Other considerations for scaleup from pilot columns (above) may also be important. The scaleup procedure recommended by Fair et al. (208) is... 

According to [116] Hmax IQ remains constant under a dynamic foaming regime when Reynolds number Re < 100 (such a tube diameter is accepted as a characteristic size). When 250 > Re > 100, Hmax/Q first increases and then decreases. Similar dependences have been observed by Pattle [117],... 

The effectiveness of the plate depends on its operating regime. If we choose the foam regime, the vapor has little kinetic energy and, to encourage its dispersion in the liquid, many authors have suggested that numerous holes with small diameter (say, 3 mm, for instance) would lead to a large interfacial area. 

Thus, we are in the foam regime. Note that that correlation of Jeronimo et al. [JER 73] gives a smaller value for but that value corresponds to a jet operation of only 70% of the holes. 

Witii these data, we have obtained the nature of the regime, which is a foam regime. We therefore need to employ the value a. ... 

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