Nonlinear analysis on fluctuation feature of two-phase flow through a T-junction

Several measurement methods of chaos dynamics were employed to analyze differential pressure fluctuations of two-phase flow through a T-junction with the aim to make clear the two-phase flow behavior splitting at a T-junction. These results may be significant for better understanding the flow structure and also for establishing valid models different from conventional viewpoints. These methods included: power spectral density and Hurst exponent, Lyapunov exponent, correlation dimension, pseudophase-plane trajectory. The experimental test section is a symmetrical and vertical impacting T-junction with 15 mm inner diameter for the main tube and two horizontal branches. Three kinds of flow pattern including bubble flow, churn flow and annular flow in the inlet tube, were investigated by detecting time series of differential pressure. It is demonstrated that two-phase flow splitting at a T-junction is a complicated nonlinear dynamic system. The Hurst exponents were larger than 0.5 showing that the flow behaviors studied are partly chaotic. The largest Lyapunov exponent greater than zero confirms the chaotic feature of two-phase flow at a T-junction in quality. Correlation dimensions were used to quantify the identified chaotic behavior.