下倾管段塞流液塞频率波动的非线性分析

Fluctuation analysis of slug frequency for two-phase slug flow in a downwardly inclined pipe

利用非线性分析技术中的分形理论,在长24·73m、内径0·05m的小型气液两相流实验装置上对下倾管空气-水段塞流中的液塞频率波动特性进行了研究.结果表明,液塞频率的波动是对初始条件敏感的混沌振荡,遵循分形统计规律,具有持久性.折算液速小时,液塞频率波动的长程相关性随着混合速度的增大而减弱,液塞频率波动对初始条件的敏感程度增强,折算液速较大时则相反.管线倾角越大,液塞频率对初始条件的敏感程度受混合速度的影响越小.折算液速和混合速度均较大时,液塞频率的混沌程度受管线倾角的影响较小.

The fluctuation characteristics of slug frequency was investigated on the basis of fractal theory for air/water slug flow in a downwardly inclined pipe. The results showed that the fluctuations was some chaotic vibrations which was sensitive to initial conditions. The results also indicated that the fluctuation obeyed fractal statistics law, and kept permanent characteristics. By carrying out an analysis about the fluctuation of slug frequency at two superficial liquid velocities, it was found that long-range dependency of slug frequency fluctuation were weakened with the increase of mixture velocity and the fluctuation was more sensitive to initial conditions when superficial liquid velocity was low, and the sensitivity of slug frequency to initial conditions was less affected by superficial mixture velocity when angle of pipe inclination became larger, but the angle of pipe inclination had less influence on the chaos of slug frequency on condition that superficial liquid velocity and superficial mixture velocity were large.