Developing low-emission aircraft conditioning systems: ISAE-SUPAERO and Liebherr-Aerospace Toulouse join forces

Hand in hand to develop air-conditioning systems for future carbon-free aircraft. Partners for 25 years, ISAE-SUPAERO and Liebherr-Aerospace Toulouse are strengthening their collaboration through an industrial chair. This initiative, co-financed by the French National Research Agency (ANR), aims to stimulate cooperation between public and private research players. Entitled CASTOR, "Chair in Radial Turbomachinery Aerodynamics", it began on January 1, 2024, and will run for 4 years.

The aim is to make progress on the design of radial turbomachinery stages, which are at the heart of the air systems designed by Liebherr-Aerospace Toulouse, and on which ISAE-SUPAERO has cutting-edge skills and research infrastructures.

This work will give rise to three theses, two post-doctorates and the creation of a research engineer position, with the support of teams from the Aerodynamics, Energetics and Propulsion (DAEP) department at ISAE-SUPAERO and Liebherr Aerospace Toulouse. A doctoral student and a post-doctoral fellow are due to arrive at the ISAE-SUPAERO site in February. The total amount of 1.250 million euros, half financed by Liebherr-Aerospace Toulouse and half by the ANR, will be used to finance equipment and subcontracting work.

Adapting the sizing of components

"In an aircraft, the air conditioning system regulates pressurization, temperature and air renewal within the cabin", explains Professor Nicolas Binder of DAEP. "In other words, it is essential for passenger safety and comfort. Traditionally, compressed air is drawn from the engines. But new low-carbon motorization systems require independent air-conditioning systems. To do this, we need to adapt the sizing of the components, which must satisfy new constraints. The CASTOR Chair’s research is part of this evolution."

Radial turbomachines are key elements in the air-conditioning system manufactured by Liebherr-Aerospace Toulouse. They comprise turbine and compressor stages. When designing them, the shape of the blades must be finely optimized to obtain the best energy yields. And this applies regardless of the aircraft’s flight phase. "This requires a high degree of operating flexibility, without compromising performance", explains Nicolas Binder. This design stage is essential in order to offer aircraft manufacturers more energy-efficient air-conditioning systems for future low-emission aircraft.

Researchers will be exploring several avenues. Unconventional radial turbine configurations will be calculated and tested, to improve efficiency and operating ranges. Compressor stability will be assessed. Likewise, efforts will be devoted to advancing numerical and experimental methods.

The research initiated by the CASTOR Chair opens the way to many applications beyond the aviation sector. "Many decarbonized systems involve this type of turbomachinery", emphasizes Nicolas Binder.

A win-win partnership

For Liebherr Aerospace Toulouse and ISAE-SUPAERO, this chair represents an opportunity to intensify their collaboration and structure a joint research program.

It enables the firm from Toulouse to mobilize and finance over the long term the cutting-edge skills present in ISAE-SUPAERO’s research laboratories, in the service of its future products. Thanks to this collaboration, Liebherr Aerospace Toulouse will be able to continue offering key technologies for the decarbonization of aviation, with more efficient air systems that consume as little energy as possible for future aircraft.

For ISAE-SUPAERO, it symbolizes recognition of the relevance and applicability of its research teams’ work by the French Ministry of Higher Education, Research and Innovation. What’s more, the resulting substantial funding will enable the institute to develop its experimental and digital capabilities.

Thumbnail: © Liebherr Aerospace Toulouse SAS