Session: 06-11 Innovations in Steam and Bottoming Cycles

Submission Number: 178515

Heat Exchanger Design for Aero-Engine Waste Heat Recovery 

Modern aircraft engines operate with thermal efficiencies in the range of 40–45%, resulting in 55–60% of the fuel energy being rejected as high-temperature waste heat. Recovering this waste heat through a bottoming cycle presents a promising pathway to enhance overall propulsion efficiency. The Air Bottoming Cycle (ABC), which utilizes air as the working fluid, offers distinct advantages for aerospace applications due to its compatibility with existing engine architectures and the avoidance of complex heat exchangers. However, implementing ABC systems in flight environments remains a significant challenge, constrained by strict limits on weight, volume, thermal loads, and the need for robust performance at variable operating conditions. 

This paper presents a performance assessment of state-of-the-art (SoA) heat exchangers using literature correlations for waste heat recovery (WHR) in aero-engine applications. An automated optimization framework—developed using HEEDS, STAR-CCM+, and Python—was employed to enhance fin geometries for improved thermal performance. In parallel, the performance of additively manufactured (AM) fin, as reported in recent studies, was evaluated. The optimized designs were benchmarked against current SoA configurations, demonstrating significant improvements in heat transfer efficiency and pressure drop characteristics. Furthermore, this study identifies and discusses key challenges in implementing high-temperature WHR heat exchangers in aerospace environments, including material limitations, thermo-structural performance, and system-level integration constraints. The findings provide valuable insights toward enabling practical, high-efficiency WHR solutions for next-generation aviation propulsion systems.

Presenting Author: Changmin Cao Collins Aerospace Ireland

Presenting Author Biography: Changmin Cao is Technical Fellow, AeroThermalFluid at the Applied Research and Technology organization of Collins Aerospace, Ireland. She graduated with a PhD degree in Thermo-physics engineering from the University of Science and Technology of China in 2015. She has extensive experience in the area of fluid and fire dynamics, heat transfer, and multi-physics modelling. Cao has authored and co-authored over 25 peer-reviewed publications in international scientific journals and conferences. She has over 10 granted patents and number of under review patent applications in her technical areas.

Authors:

Changmin Cao Collins Aerospace Ireland
Hariharan Kallath Collins Aerospace Ireland
Herol Dsouza Collins Aerospace Ireland
Jeonghoon Heo Collins Aerospace Ireland
El Hassan Ridouane Collins Aerospace Ireland
Christopher Mcnab HS Marston Aerospace
John Mccormick HS Marston Aerospace
Berwyn Pollard HS Marston Aerospace