Kinetic Theory Modelling of Liquid-Vapour flows at the Micro/Nano Scale

Abstract:
The liquid-vapor phase change is a complex, multiscale process which involves length scales spanning many orders of magnitude. When the characteristic spatial scale has a macroscopic size, the liquid and vapor bulk phases are well described by hydrodynamic equations. In contrast, the structure of the liquid-vapor interfacial region is more complex, with sharp gradients in flow variables bringing in to play additional physical effects which must be accounted for in order to connect the two hydrodynamic domains. The talk focuses on the kinetic theory modelling of fluid flows involving phase change based on the Enskog-Vlasov equation. In spite of its approximate nature, this kinetic equation has the capability of handling both the liquid and vapour phases, including the interfacial region. Therefore, the Enskog-Vlasov equation is a useful bridge between the continuum approaches, which fail to properly deal with the complexities of interfacial phenomena, and the Molecular Dynamics (MD) simulations which require a huge computational effort. After a brief overview of the basic elements of kinetic theory, the Enskog-Vlasov equation is presented and some applications are briefly discussed. These include the drag coefficient of nano-sized particles, the formation/breakage of liquid menisci in nanochannels, and the impact of micro/nano-sized droplets on solid surfaces.

Bio:
Livio Gibelli is Lecturer in Mechanical Engineering at the University of Edinburgh. He received his PhD in applied mathematics from the Politecnico di Milano and, prior to the current position, he worked as Research Fellow at the University of Warwick, Politecnico di Milano, Politecnico di Torino, and University of British Columbia. His main research interests include non-equilibrium multiphase fluid flows, the continuum description of slightly rarefied gases, the numerical methods for solving kinetic equations, and the modelling of crowd dynamics.