Pressure Drop Correlations of Two-Phase Bubble Flow in Rolling Tubes

A series of experimental studies of frictional pressure drop for single water phase and gas-liquid two-phase bubble flow in two different rolling angles and three different rolling periods were carried out in the paper.Based on the experimental data,a new correlation for calculating single-phase frictional coefficient under rolling condition was presented,and the calculations not only were agreed well with the experimental data,but also could display the periodically dynamic characteristics of frictional coefficients.Applying the homogeneous flow model,two-phase frictional pressure drop of bubble flow in rolling tubes could be caculated,and the results showed that the relative error between the calculation and experimental data was less than ±25%.