Predicting Pressure Drop and Liquid Holdup in Multiphase Flow Through a Pipeline

Lili Lyddon

December 5, 2006

A number of correlations are available for predicting pressure drop and liquid holdup in multiphase flow through a pipeline. None of the available correlations is 100% accurate. The GPSA Engineering Data Book, 12th edition (2004), emphasizes the complexity of multiphase flow and points out that “errors in calculated two-phase pressure drops in the order of plus or minus twenty percent may normally be anticipated, especially in circumstances where fluid velocities are unusually high or low, where terrain is rugged, or where fluid properties are inadequately known. In addition, different two-phase flow correlations may give significantly different pressure drops.” Methods based on flow regime can have discontinuities at the regime boundaries, while methods that ignore flow pattern may be unable to model the effects of intermittent or separated flow. When modeling multiphase flow, several correlations should be used and compared, especially if you have actual data for comparison.

Authored by Lili Lyddon - BR&E Technical Support / Help Author