Colloquium: Pietro Colonna (FPT)

The demand for efficient energy solutions is driving innovation in waste heat recovery (WHR) systems, which convert wasted thermal energy into usable power. This thesis investigates integrating the thermal recuperation of a WHR-Organic Rankine Cycle (ORC) system within an aircraft engine, introducing the Tr-HEX (Turbine-Heat Exchanger) concept. The study focuses on a regenerative diffuser, where the turbine diffuser also functions as the WHR system’s recuperator, minimizing weight and volume—critical requirements for airborne applications. Using the in-house N1D-Flow computational code, the aero-thermal behavior of fluids with varying molecular complexity in quasi-one-dimensional swirling flows is analyzed, modeling effects such as heat transfer, area variation, and viscous friction. The findings highlight potential performance improvements, including enhanced pressure recovery and reduced boundary layer separation, alongside preliminary geometrical adaptations for heat regeneration. This work demonstrates the feasibility of Tr-HEX, offering a promising pathway for integrating WHR into propulsion systems for sustainable aviation.

Supervisor: Dr. M. Pini