Dynamics of Rigid Fibers in a Planar Converging Channel

Extensional flow;Orientation diffusion model;Paper forming;Fiber orientation;Planar contraction;Turbulence

Brown, Matthew Lee ; Engineering Chemical Engineering

University:Georgia Institute of Technology

Department:Engineering

关键词: Extensional flow;    Orientation diffusion model;    Paper forming;    Fiber orientation;    Planar contraction;    Turbulence;   

Others  :  https://smartech.gatech.edu/bitstream/1853/6894/1/brown_matthew_l_200505_phd.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

The influence of turbulence on the orientation state of a dilute suspension of stiff fibers at high Reynolds number in a planar contraction is investigated.High speed imaging andLDV techniques are used to quantify fiber orientation distributionand turbulent characteristics. A nearly homogenous, isotropic gridgenerated turbulent flow is introduced at the contraction inlet.Flow Reynolds number and inlet turbulent characteristics arevaried in order to determine their effects on orientationdistribution. The orientation anisotropy is shown to be accuratelymodelled by a Fokker-Planck type equation. Results show thatrotational diffusion is highly influenced by inlet turbulentcharacteristics and decays exponentially with convergence ratio.Furthermore, the effect of turbulent energy production in thecontraction is shown to be negligible.Also, the results showthat the flow Reynolds number has negligible effect on thedevelopment of orientation anisotropy, and the influence ofturbulence on fiber rotation is negligible for $mathrm{Pe_r}>$10. It was concluded that inertia induced fiber motion played anegligible role in the experiments.