Spatial and Temporal Behavior of the Density Field in Flowing Cohesive Powders

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National Science Foundation - Division of Chemical &Transport Systems Particulate & Multiphase Processes Program (1415)ABSTRACTProposal Number: 0553819Principal Investigator: Tomassone, SilvinaAffiliation: Rutgers University New BrunswickProposal Title: Spatial and Temporal Behavior of the Density Field in Flowing Cohesive PowdersThis proposal focuses on the development of experimental and computational methods for achieving enhanced understanding of the behavior of the density of cohesive powders used in catalyst, food, and pharmaceutical manufacturing, as a function of the flow parameters and material properties. The overall goal of the proposal is to develop a predictive methodology that combines experiments and numerical simulations to characterize cohesive materials, focusing on the understanding of density functions and dilation effects. A general experimental method for quantifying density fluctuations in granular materials, based on the use of X-Ray micro computerized tomography (CT) will be implemented. Computational approaches, based on the Discrete Element Method, for predicting granular density will be obtained using materials primarily used in catalyst manufacturing (Silica and Alumina) and in food and pharmaceutical products (microcrystalline cellulose and lactose) for three types of flows used in powder processing: tumbling blenders, high shear blenders, and vibratory shakers.Intellectual Merit: A unifying theory for granular flow phenomena comparable to the one for fluids does not yet exist. Though significant progress has been made for non-cohesive powders, the field of cohesive powders remains relatively uninvestigated. This project will develop experimental and computational tools to characterize the behavior of the density field in cohesive powders, and to unravel the coupled interactions of shear, stress, and density, which is an important step required to obtain constitutive relations for cohesive granular materials.Broader Impact: The proposed research program will have direct impact on the catalyst, pharmaceutical and food industries, by promoting a better understanding of the density of materials important to these industries. Methods obtained from this work can be expanded to examine density in many powder flows. The educational impact of the work will be maximized by making optimum use of existing educational infrastructure, including an IGERT in Pharmaceutical Engineering.