(732c) Evaluating Mixing Performance of a Resonant Acoustic Mixer Both Experimentally and Using a Coupled Lbm-DEM Technique

Bladed mixers are widely used in many industrial processes that require mixing of a liquid phase and a solid phase (pharmaceutical, polymers, cement, propellant, etc.). Resonant acoustic mixing (RAM) is a non-contact mixing method that uses low frequency vibration to promote mixing and is a relatively new alternative to mix complex blends. RAM mixers are touted as being able to enhance mass transport, require a shorter time to mix, and apply less shear to the materials than bladed mixers, all valuable characteristics for mixing materials that are sensitive to shear and/or highly viscous. Nevertheless, the operation of this class of device is not well understood and little formal literature research is available. The primary purpose of this project is to evaluate the mixing performance of a highly-loaded solid phase within a viscous liquid using a RAM device. Our methodology involves both experimental and computational examination of this device. First, we develop a code that mimics the RAM and captures the fluid flow using the lattice Boltzmann method (LBM) in three dimensions. This model is coupled with the discrete element method (DEM) in order to elucidate the impact of particle loading on the operation of this mixer. Experimentally the effect of the size of the particles in a bimodal mixture and that of the viscosity of the fluid and mixing parameters (mixing time and acceleration) on the mixing performance was examined via the uniformity of the resultant blend. In order to determine the uniformity of the blend the relative standard deviation and the mean mass fraction were used. The acceleration, bimodal distribution size and viscosity have an important effect in the mixing performance experimentally and the same trend was observed using the model.