Dr Aleksandar Ribnishki

Alex's Journey in AAPS: An Alumni Profile

Alex joined the AAPS CDT after graduating from the University of Bath with an MEng in Mechanical with Automotive Engineering. His final year was strongly focused on investigating the surface-to-volume ratio of a two-stage Wankel engine, proposing an optimised design to reduce thermal losses and improve efficiency. This experience inspired him to pursue research that combines his love for engines with his commitment to sustainability.

PhD Focus

Alex’s PhD, Multi-Objective Optimisation of Hydrogen and Ammonia Chemical Kinetic Mechanisms for Internal Combustion Engine Applications, supervised by Prof Sam Akehurst, Dr Stefania Esposito and Dr Hao Yuan, focused on improving the predictive modelling of hydrogen and ammonia internal combustion engines by creating high fidelity chemical kinetic mechanisms. Hydrogen offers a promising alternative to fossil fuels, with benefits such as carbon neutrality, high energy density, and the ability to operate under ultra-lean conditions for high efficiency and low emissions.

His research addressed key questions, including:

• What are the most accurate chemical kinetic mechanisms for internal combustion engine applications today and how accurate are they?

• What improvements can be made to existing chemical kinetic mechanisms for better accuracy and computational efficiency and how?

• How much better do optimised chemical kinetic mechanisms perform for autoignition prediction in real engines compared to traditional ones?

• What is the computational cost incurred to optimise a chemical kinetic mechanism and how much can it be reduced?

By advancing modelling techniques and exploring simplified approaches, Alex’s work contributed to the development of hydrogen and ammonia engines as a viable solution for sustainable mobility.

The Reflection on AAPS

Alex describes his time at AAPS as transformative. The programme’s interdisciplinary approach and strong industry links broadened his perspective and equipped him with skills directly applicable to his career goals. He values the collaborative environment, which allowed him to work alongside leading researchers and industry experts, and credits AAPS for providing the tools and networks to make a meaningful impact in sustainable propulsion.

To Alex, advanced propulsion systems represent the future of transportation - an ecosystem of innovative solutions designed to reduce environmental impact while enhancing performance.