Experimental characterization of polydisperse particle‐loaded flow for linear resin transfer molding injections

Abstract

This study investigates the experimental filtration of micron-scale particles of a wide granulometry through fibrous media. The method used examines a key parameter in the resin transfer molding process which is the spatial evolution of particulate filler concentration. Tests were carried out with three grades of ceramic microparticle suspensions dispersed in glycerol/water blends, injected into a quasi-unidirectional fibrous medium. The influence of process parameters was extensively studied through a series of experiments by varying initial concentrations of suspension, injection pressures, pure liquid viscosities, fiber volume fractions, and particle size distributions. A non-destructive, simple, economical, and rapid characterization method was used, which consisted of taking samples of suspensions at different points through the preform length and obtaining concentrations through density measurements. The evolution of granulometry from the inlet to the outlet was studied and the size range of retained particles was deduced. Tests revealed that the particle concentration decreased with increased sampling distance. Fiber content and particle size distribution were the most influential factors on filtration behavior. The analysis showed that the smaller-sized particles are largely deposited at the fiber's surface, while the average-to large-sized ones were either blocked at the inlet, transported to the outlet, or settled under gravitational forces.