Abstract: Holdup calculation mainly depends on empirical or semiempirical correlation at present, so the prediction of liquid holdup in undulated multiphase pipelines is very important for technological calculation. Eaton and Dukler II correlation are
the best for calculating liquid holdup in horizontal pipe, In downhill pipe, Beggs&Brills(BB) correlations cannot be adopt-ed because holdup may be less than 0.0. In uphill pipe, if holdup corresponding horizontal pipe is greater than 0.3097,other correlation should be used. BBE, BBD and MBX correla-tions are considered as better correlations at the present.

Key words: undulation, multiphase pipe flow, holdup, research