An investigation of particle deposition mechanisms during impregnation of dual‐scale fabrics with micro particle image velocimetry

Abstract

Injection moulding processing of composite materials most often includes infiltration of a thermoset resin into a multi‐scale porous fabric. Controlling the fluid flow within the multi‐scale fabric is essential for the quality of the final composite material, since the transport of fluid between regions with different scales is of importance for phenomena such as void formation and filtration of particle doped resins. Hence, the transient flow behaviour in dual scale porous media is investigated in detail with Micro Particle Image Velocimetry. These experiments show that the fluid transport between the two scales can be controlled by the injection velocity. Validation of the measured velocity fields furthermore shows excellent agreement with theory and that transport between the two scales can be substantial at the flow front but negligible up‐stream it. POLYM. COMPOS., 31:1232–1240, 2010. © 2009 Society of Plastics Engineers

Motion of dispersed carbon nanotubes during impregnation of fabrics

“…Still other mechanisms may be of high importance, such as filtration at the flow front when the fluid moves from the interbundle channels to the bundles 15,16 or filtration at fibre bundles that are directed perpendicular to the flow. [14][15][16] The former may happen since we show that only few fibres are deposited in the interbundle channels and we know from previous studies that the interbundle channels supply fluid to the bundles at the wetting flow front. 19,20 Hence, fibres moving in the interbundle channels will catch up with the wetting flow front where they can be filtrated at the interface of the bundles.…”

“…This may take place both at the wetting flow front and in the saturated flow. [14][15][16] Little is known, however, of the detailed motion of nanosized fibrous particles in composites manufacturing in general, and of their motion within and between fibre bundles specifically. A central feature of the nanofibres is that they may experience both Brownian translational and rotational motion, the intensity of which is dependent on particle characteristics, flow pattern and channel geometry.…”

Interaction between the Flow in Two Nearby Pores within a Porous Material during Transitional and Turbulent Flow

“…In fully random packing where there is no control of position or size of the pores formed the detailed geometry of most of neighboring pores affect the flow. Simplified geometries such as a unit cell (Wan 1996;Nordlund 2009) and a pore-doublet (Rose 1956;Sorbie 1995;Lundström 2008;Khayamyan et al 2014) have been used to distill the geometrical effect. Following this trend we will continue to study the pore-doublet model presented in Khayamyan et al 2013.…”

Visualization of Merging Flow by Usage of PIV and CFD with Application to Grate-Kiln Induration Machines

“…The commercial code ANSYS CFX 11.0 is used for the numerical simulations and they are validated with experiments on a physical model using Particle Image Velocimetry (PIV). PIV is a non intrusive measuring technique that measures instantaneous velocity fields in arbitrary planes in any transparent fluid (Murzyn et al, 2006;Nordlund et al, 2007;Nordlund et al, 2010;Green et al, 2010). Using PIV to validate CFD simulations has previously been done by for example van Ertbruggen et al (2008) and Ranade et al (2001).…”