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Dynamics of fibres in a turbulent flow field – A particle-level simulation technique

Srdjan Sasic (Institutionen för tillämpad mekanik, Strömningslära) ; Alf-Erik Almstedt (Institutionen för tillämpad mekanik, Strömningslära)
International journal of Heat and Fluid Flow (0142-727X ). Vol. 31 (2010), 6, p. 1058-1064.
[Artikel, refereegranskad vetenskaplig]

A particle-level simulation technique has been developed for modelling the flow of fibres in a turbulent flow field. A single fibre is conceived here as a chain of segments, thus enabling the model fibre to have all the degrees of freedom (translation, rotation, bending and twisting) needed to realistically reproduce the dynamics of real fibres. Equations of motion are solved for each segment, accounting for the interaction forces with the fluid, the contact forces with other fibres and the forces that maintain integrity of the fibre. The motion of the fluid is resolved as a combination of 3D mean flow velocities obtained from a CFD code and fluctuating turbulent velocities derived from the Langevin equation. A case of homogeneous turbulence is treated in this paper. The results obtained show that fibre flocs in air-fibre flows can be created even when attractive forces are not present. In such a case, contacts between fibres, properties of an individual fibre (such as flexibility and equilibrium shapes) and properties of the flow of the carrying fluid are shown to govern the physics behind formation and breaking up of fibre flocs. Highly irregular fibre shapes and stiff fibres lead to strong flocculation. The modelling framework applied in this work aims at making possible a numerical model applicable for designing processes involving transport of fibres by air at industrial scale.

Nyckelord: fibre model, Lagrangian particle tracking, flocculation, homogeneous turbulence



Denna post skapades 2010-11-26. Senast ändrad 2016-09-15.
CPL Pubid: 129637

 

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Institutioner (Chalmers)

Institutionen för tillämpad mekanik, Strömningslära

Ämnesområden

Teknisk mekanik

Chalmers infrastruktur