Wallis Correlation notes from Lockett, MJ. 1995. Flooding of rotating structured packing and its application to conventional packed columns. Chemical Engineering Research & Design, 73(4). pp 379-384.
- Lockett argues structured packing have a higher capacity (at same surface area) compared to random packing. He used a corrugated sheet packing.
- for flooding:
- He did not see a sharp increase in pressure drop as the onset of flooding. In contrast to a conventional (1G) column.
- Determined flooding from peak pressure drop at constant gas & liquid flow with increasing RPM. He found the peak of the curve matched observations better than the 500Pa/100RPM condition used by Singh et al.
Wallis correlation:
- developed for counter-current two-phase flows in tubes.
Equation is in the form of a straight line. So you can plot the capacity factors and find ‘m’ and ‘C’. Lockett found the lines were parallel (m = 2.14) and that the dependence of C through Ng0.25 (from a log-log plot) fitted his data well. He used literature data from conventional (1G) columns to get a flooding-predicting equation for RPBs in the form of Equation 1. He converts it to a Sherwood correlation also using algerbra, but he argues the Wallis correlation is better because it’s simpler.
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