Title: Eulerian-Lagrangian Simulation of Spray Combustion in Detonation and Rocket Engine
Time: 9:30, April.24, 2024
Place: F301, School of Mechanical Engineering
Host: XIA Xi, Assoc. Professor (Institute of Aerospace Propulsion)

Biography
Dr. Peng Zhang joined the City University of Hong Kong as an associate professor in 2022. Before that, he was an assistant and then associate professor at the Hong Kong Polytechnic University during 2012-2022. He received a Ph.D. in Mechanical and Aerospace Engineering from Princeton University in 2010 and worked as a Combustion Energy Research Fellow at Princeton University during 2010-2012. Dr. Zhang’s current research areas are droplet and spray dynamics, theoretical and numerical combustion, and theoretical chemical kinetics. He has published over 100 papers in international peer-reviewed journals in these areas (see https://www.rgcombustion.org/ for details).

Abstract
Liquid fuel has promising applications in propulsion systems, in which spray combustion is the most prevailing form of combustion. This talk will present our recent computational works on spray combustion in detonation and rocket engines. Through the utilization of the Lagrangian particle tracking (LPT) and spray equation methods, we have successfully achieved liquid-fueled detonation and dual-fuel spray impingement, respectively. In liquid-fueled detonation, we proposed a dynamic model to reflect the physical image of the droplet breakup process. This model has been implemented in OpenFOAM, and our simulation results demonstrate its ability to effectively predict experimentally determined detonation parameters. Notably, our model eliminates the need for the KH breakup time parameter, which is required by the ReitzKH-RT model to fit experimental data. Furthermore, we have conducted simulations of liquid-fueled detonation within the combustor of an oblique detonation engine. Our findings reveal distinct detonation modes that arise from varying gas/liquid ratios and breakup models employed. In dual-fuel hypergolic propellant impingement combustion, we innovatively extend the spray equation so that it describes the mixing of fuel and oxidant. Meanwhile, we have established a combustion model with coupled gas-liquid phase reactions, which can describe the combustion process of hypergolic propellants effectively. The "popping" phenomenon was discovered for the first time in the framework of numerical simulations through the first realized liquid-phase reaction. This harsh burning phenomenon is qualitatively consistent with NASA's experimental findings. Further, we explain the cause of the popping phenomenon and analyze its periodic dynamics.