SK型静态混合器湍流瞬时速度时间序列关联积分

在湍流状态（Re=3972～11916）下利用激光多普勒粒子分析仪对Φ40mm×800mm、长径比1.25的SK型静态混合器的瞬时流场进行测量。结合傅立叶频域分解和互信息函数 ，利 用小波阈值理论提取瞬时速度相关信号，基于相空间重构理论、改进关联积分和最小二乘法 对瞬时速度脉动行为进行了非线性分析和特征提取。利用关联维数D₂和K₂熵表征了其湍流特性，确定SK型静态混合器内的流场为具有自相似分形的混沌流场，关联维数在 混合器中的径向变化范围在1.3～2.7之间；随着径向位移的增大，K₂熵先减小后增 大。

Correlation integral of turbulent instantaneous velocity time series in a Kenics static mixer

The turbulent velocity time series of instantaneous flow in a Kenics static mixer with diameter of 40mm×800mm and aspect ratio of 1.25 were measured with a laser Doppler anemometer for Reynolds number in the range 3972 to 11916. The co rrelative signals were extracted with wavelet threshold theory based on Fourier transform theory and a mutual-information function. The turbulent flow characte ristics were evaluated by the correlation dimensions and by Kolmogorov entropy, which were calculated using an improved correlation integral method and least sq uare methods under state space reconstruction. The experimental results indicate d that the flow field was chaotic and self-similar fractal in character. By calculating the correlation dimensions of different points in the static mixer, the range of correlation dimensions was found to be from 1.3 to 2.7. When the radi al distance was increased, the Kolmogorov entropy initially decreased and then s ubsequently increased. 