Energy distribution in the squeezing of particles in concentrated suspension

In the present work, the squeeze flow geometry is used to investigate the properties of concentrated suspensions. The suspensions consist on hard glass spherical particles dispersed in a viscoplastic fluid. With such a material, following the solid volume fraction, the material rheological behaviour ranges from purely viscoplastic fluid to granular media. During the squeezing action, the material structure evolves with energy variation due to particle displacement and interaction. The goal of our study is to identify the effect of energy evolution on the flow properties of suspensions and detect granular contact evolution. The proposed study consists on an energy approach based on the analysis of the global squeeze force and sample height with time. The squeeze force is decomposed in a combination of an average force component and a fluctuating one. This local fluctuating component is investigated from Fourier analysis as a function of solid volume fraction and compression velocity. Results show the evolution of the energy distribution during compression and allow the flow regime modification to be evaluated.