Nonlinear dynamic analysis of large diameter inclined oil–water two phase flow pattern

We experimentally investigate the inclined oil–water two phase flow characteristics in 125 mm inner diameter pipe by using the vertical multi-electrode array (VMEA) conductance probe and mini-conductance probes. For the oil and water superficial velocities in the range of 0.0052–0.3306 m/s and inclination angle at 15° and 45° from vertical, we observe the four typical inclined oil–water flow patterns, i.e., Dispersion of oil-in-water-Pseudoslugs, Dispersion oil-in-water-Countercurrent, Transitional Flow and Dispersion of water-in-oil flow pattern. Since the mini-conductance probes are sensitive to local change of flow pattern, with the help of high speed camera, we exactly identify different flow patterns under different flow conditions by analyzing the measured signals. In addition, we also propose the inclined oil–water two phase flow pattern maps for large diameter pipe. Furthermore, we further characterize the flow patterns by applying recurrence quantification analysis and chaotic attractor geometry morphological description to VMEA signals. The results show that the proposed nonlinear analysis method is an effective tool not only for classifying different water-dominated flow patterns but also for characterizing the complex flow structure of inclined oil–water two phase flow system.