Abstract

The transportation sector's significant contribution to global emissions, primarily through internal combustion engines (ICEs), has intensified the search for cleaner alternatives. Hydrogen (H2), with its zero carbon emissions, is a promising candidate. However, its highly reactive nature and low density present challenges in achieving stable combustion, necessitating precise control over injection and combustion processes. The Wankel rotary engine, known for its compact size and high power-to-weight ratio, offers both opportunities and challenges for hydrogen combustion, making it ideal for specific applications like aircraft or as a range extender in hybrid vehicles.

This research focuses on analyzing hydrogen injection and combustion in a modern Wankel engine using numerical models and three-dimensional computational fluid dynamics (CFD) simulations. The models were validated against experimental data from gasoline combustion to ensure accuracy before being applied to hydrogen. Results indicate that stable, low-emission combustion can be achieved with lean hydrogen mixtures, particularly when direct injection (DI) strategies are used. DI, especially when aligned with the engine's major axis, was found to enhance power output and reduce inefficiencies compared to port fuel injection (PFI) strategies. The study also explored the impact of nozzle geometry on mixture formation, revealing that multi-hole nozzles generated higher turbulent kinetic energy, leading to better mixing and more homogeneous charges in ICE applications.

Additionally, a modified level-set G-Equation approach was implemented to simulate flame propagation and its interaction with combustion chamber walls. The findings highlight that flame quenching, driven by gas dynamics, significantly impacts emissions predictions. This research contributes to the optimization of hydrogen combustion in Wankel engines, providing insights that could enhance the performance and environmental impact of ICEs in specialized applications.

Biography

Kevin Moreno is a Ph.D. candidate in the Mechanical Engineering Program within the Physical Science and Engineering (PSE) Division at KAUST, under the supervision of Prof. Hong G. Im. He earned his bachelor's and master's degrees in Mechanical Engineering from the National University of Colombia, Bogotá, in 2015 and 2017, respectively. Kevin began his Ph.D. studies at KAUST in 2019. His research focuses on computational fluid dynamics (CFD) applications, with particular interest in hydrogen combustion and injection modeling in internal combustion engines, including the Wankel rotary engine concept.