Characterization Of Gas/Liquid Two Phase Flow Patterns Based On The Chaotic Analysis Of Conductance Fluctuating Signals

The delay time embedding parameter has great effect on the chaotic attractor reconstruction, so one must choose an appropriate delay time in the phase space reconstruction. In this paper, firstly the Lorenz chaotic equation is taken as an example to produce a nonlinear time series, and we discussed the applicability of delay time algorithm to the presence of noise at different time series length. The study shows that the C-C algorithm of delay time is strong robustness, and the Fraser et al's mutual information algorithm and auto-correlation function algorithm are affected by presence of noise and variations of time series length and the Liebert et al's mutual information algorithm can not calculate the delay time. Based on the above studies, we characterized the gas/liquid two phase flow patterns based on the chaotic analysis of conductance fluctuating signals. The results indicate that at a low superficial water velocity, the dynamic character of bubble and churn flows become more complex and the slug flow more simple with increasing superficial gas velocity; as the superficial water velocity increases, the influence of turbulence fluctuation of water phase is stronger, the dynamic character of various flow patterns globally become more complex and locally became irregular fluctuation. It should be noticed that the fluctuation became very weak when the velocity of water increase by some values. Finally we conclude the boundary equation of bubble flow and churn flow according to the curves of chaotic correlation dimension with superficial gas velocity variations, and we find the equations with the high water flow rate are the same with the ones with low flow rate.