Multiscale Modeling and Simulation of Liquid-Vapor Phase Change

Friday, Sept. 22, 3:15 pm
Sidney & Marian Green Classroom (3550 MEK)

Yuwen Zhang, Ph.D.
James C. Dowell Professor and Chairman
Department of Mechanical & Aerospace Engineering
University of Missouri

Molecular dynamics is a computer simulation technique that the time evolution of a set of interacting molecules is followed deterministically by solving the equations of motion of classical multi-body systems following Newton’s second law. Rapid boiling of liquid water film heated by a hot copper plate as well boiling of liquid argon on a nanostructured surface are simulated using molecular dynamics. The results show that liquid molecules close to the plate are instantly overheated and undergo a rapid phase change process. The nanostructure has significant effect on evaporation /boiling of thin film. The degrees of superheat and size of nanoparticles have significant effects on the trajectories of particles and net evaporation rate. Effects of nanostructured defects of copper solid surface on the bubble growth in liquid argon have been investigated through a hybrid atomistic-continuum method. Phase change of argon on five nanostructures has been observed and analyzed. The results showed that the solid surface with wedge defect tends to induce a nano-bubble relatively more easily than the others, and the larger the size of the defect is the easier the bubble generate.

Dr. Yuwen Zhang is a James C. Dowell Professor and Chairman of the Department of Mechanical and Aerospace Engineering at University of Missouri. His research interests are in the areas of thermal-fluids science and engineering, including ultrafast and high-energy laser materials interaction, multiscale transport phenomena in multiphase systems, inverse problems and optimization under uncertainty, micro- and nanoscale heat transfer, and sustainable and renewable energy. He has published five books, over 275 journal articles, and more than 160 conference papers/presentations. He is recipients of the Young Investigator Award from the US Office of Naval Research, Senior Faculty Research Award from the College of Engineering in University of Missouri, as well as the Chancellor’s Award for Outstanding Research and Creative Activity from the University of Missouri (2010). He is a fellow of the American Association for the Advancement of Science (AAAS), and a fellow of the American Society of Mechanical Engineers (ASME). He is the Co-Editor-in-Chief for two international journals, as well as editorial board members of other 10 international journals.