CT-18 Modifications to Pressure Drop Method for Partial Reflux Condensation inside Vertical Tubes

Z. H. Yang and J. W. Holmes

HTRI has modified the pressure drop methods of two-phase friction and static head for partial reflux condensation under high outlet vapor fraction conditions. With these modifications, Xist® predictions can cover outlet vapor fractions from 0 to 0.99. The improved methods have been validated using available HTRI data, inquiry cases, and parametric studies. A critical exit velocity for droplet entrainment is also calculated from a literature method. This report documents evaluation and improvement of the methods, and recommends implementation in Xist.