Chaotic characteristic analysis of conductance signals of gas/liquid two-phase flow in vertical upward pipe
垂直上升管中气液两相流电导波动信号的混沌特性分析

In this paper, firstly the Lorenz chaotic equation is taken as an example to produce a nonlinear time series, and we discuss 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 robust. 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, with increasing superficial gas velocity, the dynamic character of bubble and chum flows become more complex, and the slug flow is affected by the liquid superficial velocity; whereas at high superficial water velocity, with increasing superficial gas velocity, the dynamic character of gas/liquid two-phase flow become simpler while the flow pattern changes from bubble flow to slug flow, and the dynamic character of slug flow shows unsteady fluctuating phenomena due to liquid phase turbulence interaction, and the dynamic character of two-phase flow becomes more and more complex while the flow pattern changes from slug to chum flow. The study shows that we can characterize the flow pattern variations of gas/liquid two-phase flow based on the chaotic analysis of conductance signals, it is a useful tool to understand flow pattern transition mechanism and its dynamic evolution character.