An Investigation of Particle Deposition Mechanisms During Impregnation of Dual-Scale Fabrics with Micro Particle Image Velocimetry

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. (C) 2009 Society of Plastics Engineers