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A. Jäsberg, P. Selenius and A. Koponen. The effect of fi brous materials on the rheology of aqueous foams. In Advances in Pulp and Paper Research, Oxford 2017, Trans. of the XVIth Fund. Res. Symp. Oxford, 2017, (W. Batchelor and D. Söderberg, eds), pp 159–173, FRC, Manchester, 2018.

Abstract

We studied fully developed pipe flow of fibre-laden aqueous foams and decoupled their bulk rheological properties boundary effects like slippage at the pipe wall. The air volume fraction of the foams varied between 70% and 75%. The addition of hardwood fibres at the consistency 20 g/kg to plain aqueous foam increased viscosity more than 100%, while with microfibrillated cellulose at a consistency of 25 g/kg the increase was about 30%. The effect of synthetic (cellulosic)rayon fibres was negligible at the consistency of 20 g/kg. All the studied foams could be described as shear-thinning power-law fluids with significant slippage at the pipe wall by particles size and interactions between particles and bubbles.


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