Churning liquid-vapor zones

Semi-annular flow. Liquid slugs were non-existent (Fig. 2.30e). A liquid film formed at the tube wall with a nearly continuous central vapor core, truncated periodically by churning liquid-vapor zones, which disappear gradually. 

Slug/semi-annular flow. Here both slug and semi-annular flows were present. The vapor velocity increased with the heat flux and the rear of elongated bubbles began to break up (Fig. 2.30d). Coalescence was no longer clean and created a churn-like zone where the liquid slug had been. 

Annular flow (wavy and smooth). A liquid film flowed on the tube wall with a continuous central vapor core without churning zones (Fig. 2.30f,g). 

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See also in sourсe #XX -- [ ]

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