非牛顿流体中在线气泡聚并的混沌特征

Chaotic Characteristics of in Line Bubble Coalescence in Non-Newtonian Fluid

利用光电信号采集系统测定了非牛顿流体中伴有聚并现象的在线连续上升气泡的通过频率信号,并采用基于相空间重构技术的混沌时间序列法对其进行了分析.相图和Cao算法计算结果定性表明了非牛顿流体中伴有聚并现象的在线连续气泡上升行为具有混沌吸引子特征,服从确定性的混沌运动机理.最大Lyapunov指数量化分析表明在线连续气泡上升行为的混沌特征与聚并程度密切相关:气泡行为的混沌程度随聚并程度增大而增大,增大气速易于导致气泡行为混沌程度增大.

The frequency signal of continuous rising bubbles with coalescences in non-Newtonian fluid was measured by means of a photoelectrical signal collection system and analyzed using chaotic time series analysis based on the phase space reconstruction.The results of phase portrait and Cao＇s method show qualitatively that the in-line continuous bubble rising behavior with coalescence in non-Newtonian fluid follows a deterministic and chaotic motion mechanism with the characteristics of chaotic attractor.The largest Lyapunov exponents quantify that the chaotic characteristics of the in-line continuous bubble rising behavior are closely related with the coalescence degree.The chaotic degree of bubble behavior increases with the coalescence degree and increasing the gas flowrate tends to increase the chaotic degree of bubble behavior.