Characterization of oil/water two-phase flow patterns based on symbolic time series analysis

The flow patterns of oil/water two-phase flow in vertical upward pipes have been characterized by the analysis of symbolic time series based on the conductance fluctuating signals. It is shown that the temporal irreversibility and chi-square statistics have little changes with oil-in-water flow pattern variations for flow conditions of 61% ≤ K_W ≤ 91% and are sensitive to transitional flow pattern variations of K_W = 51%. The characterization of flow patterns is strongly supported by the flow map of our previous study based on Kinematic wave theory. The symbolic time series analysis can be a new tool for flow pattern identification in vertical upward oil/water two-phase flow pipes.