摘要
研究了内径383mm、高径比（H／D）为1～3、多管布气的浅层气液两相鼓泡塔内的压力波动信息的非线性混沌特性。通过差值准相空间构造吸引子法确定重构相空间的时间延迟。探讨了不同高径比、不同轴向位置下表观气速对非线性混沌特性的影响。鼓泡塔不同区域的奇怪吸引子结果表明：对于HD≤3的气相多管分布的浅层鼓泡塔，沿轴向可区分为下部气泡分裂区、中部分裂与凝并过渡区和上部分裂凝并平衡区。鼓泡塔中存在小尺度的气泡运动、中尺度的气泡涡旋运动和大尺度的涡旋流动。其混沌特征参数具有多值性。高频小尺度的气泡破碎凝并的复杂非线性动力学运动特征。需要3～4个参数加以描述；鼓泡塔上部气泡运动的规则性加强。动力学描述所需参数减少至2～3个；Kolmogorov关联熵在uk=0．15～0．25m/s内存在极小值。表观气速可以得到优化。
In the present paper, the nonlinear behaviors of the chaotic bubbling from a 4-pipr gas sparger in a shallow bubble columns with three different high diameter ratios of one to three was studied. The superficial gas velocity was varied widely within 0. 045-0. 312 m/s. The nonlinear chaotic analysis is performed with the time series data of wall pressure fluctuation measured byaprobe. The time delay was estimated by differential phase space reconstruction method. The strange attractors were constructed, the lower column region of which is complex while the upper is simple. To explain such chaotic behaviors of bubbling, the columns were proposed to have three regions： the lower bubble split region, the middle transition region of bubble split and coalescence, and the upper balance region of bubble split and comescence. While estimating the chaotic invariants including correlation dimension and Kolmogorov entropy at the given operation condition, the multi-value phenomena were observed, indicating that a multi-scale behavior occurred in such gas-liquid bubble column systems. The values of Kolmogorov entropy are positive and finite, and the values of correlation dimension were up to 3.5. Based on the estimates of correlation dimension, it was found that at least 3~4 independent variables are needed in order to describe the high frequency small scale bubble flow behavior of such system in the lower region and at least 2-3 independent variables in the upper region. The Kolmogorov entropy has minimum values as the function of gas superficial velocity at the range of 0.15-0.25 m/s.
出处
《华东理工大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2008年第4期461-466,490,共7页
Journal of East China University of Science and Technology
基金
上海市重大基础项目资助(05DJ14002)
关键词
浅层鼓泡塔
非线性
压力波动
混沌
多尺度
shallow bubble column
nonlinear
pressure fluctuation
chaos
multi-scale
