纤维悬浮槽道湍流中纤维取向分布和流变特性

为了解悬浮槽道湍流中纤维取向分布和流变特性，对纤维悬浮湍流进行了理论分析和数值模拟.推导了纤维取向平均概率分布函数方程，得到了脉动流场速度和脉动取向概率分布函数关联项，建立了关联项与平均概率分布函数梯度以及扩散系数之间的关系，数值求解了平均概率分布函数的方程.计算结果表明，随着长径比的增大，纤维的轴向更趋向于流动方向；悬浮流的剪切应力和第一法向应力差由壁面到槽道中心逐渐接近于0；剪切应力几乎不随长径比和体积分数变化，而第一法向应力差的绝对值随体积分数的增大和长径比的减小而增大.

Orientation distribution of fibers and rheological property in turbulent channel flow of fiber suspensions

To explore the orientation distribution of fibers and rheological property in turbulent channel flow of fiber suspensions, the fiber suspensions in turbulence were theoretically analyzed and simulated. The equation of probability distribution function for mean fiber orientation was derived, and the correlation of fluctuating fluid velocity and fluctuating orientation probability distribution function was obtained. The relationship between the correlation of two fluctuating quantities and the gradient of mean orientation probability distribution function with the diffusion coefficient was built. The function of average probability distribution was solved numerically. The simulation results show that the fibers align along the flow direction more obviously with the increasing fiber aspect ratio. The shear stress and the first normal stress difference are close to 0 from wall to the centerline. The shear stress does not vary as the fiber aspect ratio and fraction of volume, while the absolute value of the first normal stress difference increases with the increasing fraction of volume and the decreasing fiber aspect ratio.