MODELING AND SIMULATION OF MULTIPHYSICAL PROCESSES IN PARTICULATE MEDIA

Speaker: Dr. Tarek Zohdi, California State University-BerkleyAbstract:
Recently, several applications, primarily driven
by micro-technology, have emerged where a successful
analysis requires the simulation of flowing particulate media involving simultaneous near-field interaction between charged particles and momentum exchange through mechanical contact. For example, industrial processes such as Chemical Mechanical Planarization (CMP), which involves using chemically-reacting particles embedded in fluid (gas or liquid) to ablate rough small-scale surfaces flat, have become important for the success of many micro- and nano- technologies. Charged material can lead to inconsistent ``clean'' manufacturing processes, for example, due to difficulties with dust control, although intentional charging of particulate material can be quite useful in some applications, for example involving electrostatic copiers, inkjet printers, powder coating machines, etc. The presence of near-field interaction forces can produce particulate flows that are significantly different than purely contact-driven scenarios. The determination of the dynamics of such materials is important for the accurate description of the flow of powders, which form the basis of micro-fabrication. Near-field forces can lead to particle clustering, resulting in inconsistent fabrication quality.
Therefore, neglecting such near-field effects can lead to a gross miscalculation of the characteristics of such flows.
Thus, an issue of overriding importance to the successful characterization of such flows is the development of models and reliable computational techniques to simulate the dynamics of multibody particulate systems involving near-field interaction and contact simultaneously (including thermal effects).Ideally, in an attempt to reduce laboratory expenses, one would like to make predictions of a complex particulate flow's behavior by numerical
simulations, with the primary goal being to minimize time-consuming
trial and error experiments. A central objective of this presentation is to provide basic models and numerical solution strategies for the direct simulation of flowing particulate media that can be achieved within a relatively standard desktop or laptop computing environment. Also, if time permits, the closely related topic of ``swarms'' is discussed.
The topics to be touched upon are:(1) Particulate flows(2) Related problems in swarm modeling(3) Optical (electromagnetic energy) propagation(4) Acoustical (mechanical energy) propagation(5) Degradation/aging of particulate continua and(6) Related problems in electromagnetic materials

Location: Kaprielian Hall (KAP) - 209

Audiences: Everyone Is Invited

Contact: Evangeline Reyes