Impact of Puller Fan Integration on the Design and Off-Design Performance of a Hybrid-electric Fuel Cell Aircraft Thermal Management System

Kurzfassung

Thermal management systems (TMS) are a key challenge for aircraft fuel-cell (FC) propulsion. Ram-air heat exchangers (HX) lose performance under off-design conditions, especially on the ground. Adding a puller fan can improve heat rejection, but existing studies often use simplified fan models. The study aims to improve this approach by coupling a fan map with the HX duct system resistance curve, assessing its impact on aircraft mission performance in terms of cooling drag and fan power. The work is conducted within the Clean Aviation EU-funded project TheMa4HERA, using as reference the HERA UCB concept. A TMS architecture with fan might be beneficial in terms of mass and energy savings compared to a concept that uses a battery to support ground operations. Assuming a simple fan model with constant efficiency and pressure ratio is found to be a reasonable approximation, capturing key aircraft-level effects with lower modeling effort.