Description: A novel and physically correct molecular dynamics simulation model for the solid wall-fluid heat transfer boundary condition has been developed to capture the physics of transient phase transition of a nano-scale liquid argon film on a heated platinum surface. The eventual colloidal adsorption phenomenon on the platinum surface is precisely simulated for the first time as the evaporation is diminishing. The objective of this work is to provide microscopic characterizations of the dynamic thermal energy transport mechanisms during the liquid film evaporation and also the resulting non-evaporable colloidal adsorbed liquid layer at the end of the evaporation process. A nanochannel is constructed of platinum (Pt) wall atoms with argon as the working fluid. The proposed model is validated by heating liquid argon between two Pt walls and comparing the change in internal energy to that calculated from thermodynamic properties of argon. Phase change process is studied by simulating evaporation of a thin liquid argon film on a Pt wall using the proposed model. The gradual evaporation, initiated by rigorous jet convection, exponentially decreases with time. A non-evaporating thin film is eventually resulted and the factors governing its thickness are identified. A new method based on the current molecular dynamics simulation is developed and used to evaluate the Hamaker constant for the "adsorbed" film and the Hamaker constant compares well with the experimental value.

Biography: Jacob N. Chung is the Andrew H. Hines, Jr./Progress Energy Eminent Scholar Chair Professor in the Department of Mechanical and Aerospace Engineering at the University of Florida. He is also the Director of micro-Scale and Microgravity Fluid Mechanics and Heat Transfer Lab at the University of Florida. He is a fellow of the American Society of Mechanical Engineers (ASME). From 2002-2005, he served as an associated editor for the ASME Journal of Heat Transfer in the areas of phase-change heat transfer and multiphase flows. He is a member of the ASME Heat Transfer Division K-11 and K-19 committees. Dr. Chung's research activities for the past thirty years have been in the general areas of fluid mechanics and heat transfer with a special focus on bubble and droplet dynamics and heat transfer, phase change heat transfer, multiphase flows, microgravity boiling, laminar-turbulent transition, turbulence in heated flows, nano- and micro-scale thermal transport phenomena, and cryogenic two-phase heat transfer. He has authored and co-authored a total of 120 archival journal papers in the above research areas. Dr. Chung and two co-authors published a book entitled "Transport Phenomena with Drops and Bubbles".