(101c) Distinguishing and Prediction Periodic and Chaotic Multiphase Flow in T-Junction Microchannel Obtained from Optical Time-Series Signals

The stability and regularity of multiphase flow in T-junction microchannel were investigated in this study. In virtue of homemade optical measuring system, time series related to two-phase flow dynamics under different operating conditions, fluids and channel lengths were collected and analyzed through a nonlinear characteristic parameter of Kolmogorov entropy (K_E). The results reveal that higher K_E corresponds to irregular and unstable flow behavior, while the lower K_E refers to desirable operating condition with steady and orderly flow behavior. Meanwhile, most of the Taylor flow regime appeared at proper operating conditions with small K_E presented steady flow behavior. In order to further understand and estimate K_E, a concise equation derived from definition of K_E was proposed, which included bubble break-up impact and flow rate ratio of gas and liquid. Results of the calculations and the experiments were in good agreement. The derived equation possesses effectiveness to identify and ensure stable and predictable multiphase flow in microchannel.