Two phase flow regions estimation

VsL is superficial liquid velocity, in ft/sec QL is liquid volume flow in ft3/sec A is line inside cross sectional area, in fl2. 

The two phase flow patterns in horizontal line are bubble, plug, stratified, wavy, slug, annular, and spmy (dispersed), in the order of increase vapor flow. These flow regions will be affected by fluid pressure, line size, liquid surface tension, and line inclination (see [4J p. 7-14 for more details). 

The two phase up-flow patterns in vertical hne are bubble, slug, forth (or chum), annular, mist, in the order of increase vapor flow. A generally accepted down-flow two phase flow regions are not available. 

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