垂直上升管中气液两相流电导波动信号的混沌特性分析

首先以Lorenz混沌方程产生的非线性时间序列为例，讨论了在不同时间序列长度下各种延迟时间算法对噪声的适用性.研究发现，采用C_C算法计算延迟时间的鲁棒性强.在此基础上，给出了垂直上升管中气水两相流电导波动信号混沌表征结果，发现在较低水相表观速度时，随着气相表观速度增加，泡状流及混状流动力学特性变得愈加复杂，而段塞流动力学特性受液相表观速度影响较大；在较高水相表观速度时，随着气相表观速度增加，当流型从泡状流向段塞流转变时，气液两相流动力学特性变得相对简单.但是，由于受液相湍流作用影响，段塞流的动力学特性表现出了涨落现象，呈现不稳定性，当流型从段塞流向混状流转变时，气液两相流动力学特性则变得愈加复杂.研究结果表明：基于电导波动信号的混沌分析可以较好地表征气液两相流流型变化，是理解流型转变机理及其动力学演变特性的有用工具.

Chaotic characteristic analysis of conductance signals of gas/liquid two-phase flow in vertical upward pipe

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.