Fluid mechanics of fibre suspensions related to papermaking - DiVA
Fluid mechanics of fibre suspensions related to papermaking - DiVA
Fluid mechanics of fibre suspensions related to papermaking - DiVA
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3.4. PULP SUSPENSIONS 23<br />
motion was calculated in a two-dimensional shear flow at moderate Reynolds<br />
number. A very recent work by Tornberg & Shelly (2004) numerically studied<br />
the dynamics <strong>of</strong> flexible <strong>fibre</strong>s in S<strong>to</strong>kes flow. Tornberg and Shelly used a<br />
non-local slender body theory and could obtain shear induced buckling and<br />
relaxation <strong>of</strong> the filaments, leading <strong>to</strong> an elastic energy concepts, which is very<br />
unique for a <strong>fibre</strong> suspension compared <strong>to</strong> suspension <strong>of</strong> spherical particles.<br />
In general, these effects are implicit in non-New<strong>to</strong>nian <strong>suspensions</strong>, however<br />
in pulp <strong>suspensions</strong> at low concentrations, viscosity may be simplified <strong>to</strong><br />
being constant and thus independent <strong>of</strong> the flow field. This implied that the<br />
suspension can be treated as New<strong>to</strong>nian as a first approximation. Simulations<br />
involving modelling <strong>of</strong> pulp <strong>suspensions</strong> are in their initial stage, however extensive<br />
experimental studies <strong>of</strong> pulp <strong>suspensions</strong> have been undertaken in parallel<br />
with the development <strong>of</strong> <strong>papermaking</strong> machines.
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