C5.2 - AER-X: Airbone Energy Recovery via vapor eXpansion

Motivation

In recent years, there has been a growing interest in harnessing waste heat in various industrial applications. A particularly promising avenue involves the integration of ORC (Organic Rankine Cycle) turbines into contemporary airborne propulsion systems. Essential to this initiative is the challenge of defining the optimal design of propulsion architectures that incorporate WHR-ORC (Waste Heat Recovery - Organic Rankine Cycle) systems. This requires a multidisciplinary approach which combines engineering expertise from various fields. Moreover, the design of turbomachinery operating with non-ideal compressible flows (NICF) is a critical aspect. Developing best-design practices in this context is essential to ensure the reliability and efficiency of these systems.

Objective

The project aims to demonstrate the feasibility of ultra-compact airborne ORC systems and to develop a multidisciplinary methodology for achieving an optimal design integration. The design focuses on maximising the energy recovered. However, special attention is given to compactness and to the impact on the overall propulsion performance. In this regard, optimal placement of heat exchange components is considered to minimise their footprint and weight. Furthermore, potential additional propulsion configurations, including electric hybrids powered by the ORC system itself, are evaluated.

Methodology

The design will unfold on several levels, ranging from a thermodynamically beneficial design and fluid selection over topology optimisation, and ultimately to shape optimisation accounting for turbine-diffuser-volute interaction. Additionally, by utilising machine learning, as well as numerical and experimental techniques, the goal is to create an extensive database of optimal design families for several realistic boundary conditions corresponding to different propulsion architectures and flight operating conditions. This will enable the development of data-driven models to assist in the design, selection, and scaling processes of the turbomachinery operating with non-ideal fluids. Lastly, the feasibility of implementing regenerative diffuser concepts in airborne ORC turbines is under evaluation to further enhance their compactness.