Mechanisms of flow-induced deformation of porous media

Hellström, J. Gunnar I.; Frishfelds, Vilnis; Lundström, T. Staffan

doi:10.1017/s002211201000368x

Cited by 31 publications

(51 citation statements)

References 28 publications

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“…Attempts have been made to include void formation mechanism during impregnating flow 7,19 or drag forces to describe movement of filaments during saturated flow. 20,21 The latter suggests that the permeability can change significantly if the fibre arrangement moves. Experimental evidence for movement of individual filaments in liquid composite moulding processes at low fluid velocities and the required drag force was not provided.…”

Section: Introductionmentioning

confidence: 99%

Influence of the micro-structure on saturated transverse flow in fibre arrays

Gommer

Endruweit

Long

2018

Journal of Composite Materials

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This study analyses the influence of the random filament arrangement in fibre bundles on the resin flow behaviour. Transverse steady-state resin flow that occurs behind a liquid resin flow front was simulated numerically through statistically equivalent micro-structures at high-fibre volume fractions, V f > 0.6, as observed in fibre bundles. The need of applying a minimum gap distance between neighbouring filaments was overcome by automated local mesh refinement. The derived permeability values showed significant scatter. Convergence of these values was determined at a ratio of flow length to filament radius greater than 20 for all three analysed fibre volume fractions. Mean permeabilities were between 6 and 10 times lower than those predicted for a hexagonal fibre array. A statistical model is proposed, which is able to predict the scatter of observed permeabilities based on simple micro-structural descriptors.

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Section: Introductionmentioning

confidence: 99%

Influence of the micro-structure on saturated transverse flow in fibre arrays

Gommer

Endruweit

Long

2018

Journal of Composite Materials

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“…Many researchers have modelled pore level flow, as such, theoretically or numerically, e.g. Geller and Hunt (1993), Hellström et al (2010b), Ljung et al (2012), Jourak et al (2014) and Fabricius et al (2016) and Pérez-Ràfols et al 2016). Also, experiments have been performed on simplified geometries like parallel tubes (Khayamyan et al 2014;Khayamyan and Lundström 2015).…”

Section: Introductionmentioning

confidence: 99%

Transitional and Turbulent Flow in a Bed of Spheres as Measured with Stereoscopic Particle Image Velocimetry

et al. 2017

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Stereoscopic particle image velocimetry has been used to investigate inertia dominated, transitional and turbulent flow in a randomly packed bed of monosized PMMA spheres. By using an index-matched fluid, the bed is optically transparent and measurements can be performed in an arbitrary position within the porous bed. The velocity field observations are carried out for particle Reynolds numbers, Re p , between 20 and 3220, and the sampling is done at a frequency of 75 Hz. Results show that, in porous media, the dynamics of the flow can vary significantly from pore to pore. At Re p around 400 the spatially averaged time fluctuations of total velocity reach a maximum and the spatial variation of the time-averaged total velocity, u tot increases up to about the same Re p and then it decreases. Also in the studied planes, a considerable amount of the fluid moves in the perpendicular directions to the main flow direction and the time-averaged magnitude of the velocity in the main direction, u x , has an averaged minimum of 40% of the magnitude of u tot at Re p about 400. For Re p > 1600, this ratio is nearly constant and u x is on average a little bit less than 50% of u tot . The importance of the results for longitudinal and transverse dispersion is discussed.

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“…There are several methods to do this but here a method proposed in Hellström et al [16] is applied. In this approach discrete Voronoi diagrams are used to divide the system of particles into cells, each containing one pellet.…”

Section: Discrete Modelmentioning

confidence: 99%

“…In the second strategy a discrete micro-level model is applied where the pore space between the pellets is divided into cells with modified Voronoi diagrams. The convective heat transfer of hot fluid flow through the system including dispersion due to random configuration of the pellets is then modelled [16,19,31]. A random packing of spheres is considered and temperature distributions in time are compared resulting in conclusions about the advantages and drawbacks of respective model.…”

Section: Introductionmentioning

confidence: 99%

Modelling heat transfer during flow through a random packed bed of spheres

et al. 2017

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Heat transfer in a random packed bed of monosized iron ore pellets is modelled with both a discrete three-dimensional system of spheres and a continuous Computational Fluid Dynamics (CFD) model. Results show a good agreement between the two models for average values over a cross section of the bed for an even temperature profiles at the inlet. The advantage with the discrete model is that it captures local effects such as decreased heat transfer in sections with low speed. The disadvantage is that it is computationally heavy for larger systems of pellets. If averaged values are sufficient, the CFD model is an attractive alternative that is easy to couple to the physics up-and downstream the packed bed. The good agreement between the discrete and continuous model furthermore indicates that the discrete model may be used also on non-Stokian flow in the transitional region between laminar and turbulent flow, as turbulent effects show little influence of the overall heat transfer rates in the continuous model.

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Mechanisms of flow-induced deformation of porous media

Cited by 31 publications

References 28 publications

Influence of the micro-structure on saturated transverse flow in fibre arrays

Influence of the micro-structure on saturated transverse flow in fibre arrays

Transitional and Turbulent Flow in a Bed of Spheres as Measured with Stereoscopic Particle Image Velocimetry

Modelling heat transfer during flow through a random packed bed of spheres

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