Session: 

Paper Number: 154283

Design and Cfd Validation of Heat Exchangers in an Ammonia Aircraft Fuel System Using Supercritical Carbon Dioxide Waste Heat Recovery 

The use of alternative fuels in aviation has become critical in reducing carbon emissions and addressing global climate challenges. Ammonia is a carbon-free energy carrier, and it is gaining attention due to its high energy density. It has the ability to be cracked into hydrogen for combustion resulting in zero carbon emissions at the exhaust. In ammonia-fueled aircraft, achieving the necessary thermodynamic conditions for cracking is essential to ensure efficient hydrogen production. This paper explores the integration of a supercritical carbon dioxide (sCO2) Waste Heat Recovery System (WHRS) to provide the required thermal energy for ammonia cracking through heat exchange and the design and validation of the components. sCO2 is an ideal working fluid for this application due to its high thermal efficiency, ability to recycle exhaust heat, and capability to generate additional energy for onboard systems. By using sCO2 to transfer heat from the exhaust, the system not only heats the fuel but also contributes to the overall aircraft energy efficiency. 

Two consecutive heat exchangers are designed to deliver latent and vaporizing heating to the ammonia fuel system using waste heat from the exhaust, recycled using the sCO2 cycle. The focus of this study is the design and CFD validation of these heat exchangers, which must handle the complexities of multiphase flow and phase transitions. The challenges and strategies in optimizing heat transfer and managing multiple-phase flow are discussed in the pursuit of improving carbon emissions.  

Presenting Author: Claire-Phonie Bury University of Central Florida

Presenting Author Biography: I am a mechanical engineering graduate at the University of Central Florida (UCF). Past and current focus is on thermal management systems for aviation. Currently, I conduct research at the Center of Turbomachinery and Energy Research Lab UCF. Under the NASA ULI, I am investigating the integration of sCO2 Waste Heat Recovery System (WHRS) in an Ammonia-fueled aircraft engine, all to support decarbonation.

Authors:

Claire-Phonie Bury University of Central Florida
Alejandro Moreno University of Central Florida
Marcel Otto University of Central Florida
Erik Fernandez University of Central Florida
Jayanta Kapat University of Central Florida