Harnessing Two-Phase Detonation: Theory and Molecular Simulation of Shock-Impacted Droplet Vaporization
MIE Department Seminar
October 17, 2024
11:00 AM - 12:00 PM America/Chicago
Presenter: Nikolaos Kateris, PhD, Stanford University
Location: ERF 1043
Abstract: Pressure-gain combustion, or detonation, is a mode of combustion characterized by a shock wave coupled with heat release. Given the high speed of shocks (several km/s), detonation can be utilized for powerful, efficient and compact propulsion and power generation. However, gas-phase detonation is often unstable and difficult to control. Using liquid fuels in two-phase detonation facilitates stable and controlled detonation but raises the quantitative question of how quickly droplets undergo vaporization when impacted by a shock. A vaporization theory is therefore necessary for the continuum simulation and design of two-phase detonation engines. Molecular dynamics simulations of n-dodecane nano-droplets impacted by a Mach 5 nitrogen shock display the same dynamics observed for large droplets in experiments and reveal the momentum and energy transfer mechanisms responsible for droplet displacement and vaporization. This allows the development of a coupled momentum and energy transfer analytical theory, which reproduces experimental and simulation results spanning different fuels, thermodynamic conditions and shock strengths across several orders of magnitude in droplet size. Molecular dynamics simulations also reveal interesting physics that arise during shock-induced droplet vaporization, including supercritical and non-equilibrium phenomena.
Speaker Bio: Nikolaos Kateris is a postdoctoral researcher at Stanford University, working in the Mechanical Engineering department. He obtained his PhD in mechanical engineering from Stanford University in 2024, under the supervision of Prof. Hai Wang, after receiving his bachelor's and master’s degrees in mechanical and aerospace engineering from the University of Cambridge. His research focuses on energy conversion at a molecular scale, spanning the areas of two-phase detonation, electrochemical energy storage and carbon nanomaterials. He has served as a reviewer for research proposals and articles, and he has been the recipient of awards, such as the Anthony Kennedy Mechanical Engineering fellowship and the Ricardo Prize in thermodynamics.
Date posted
Oct 11, 2024
Date updated
Oct 11, 2024