Thermal Management System Modelling for Liquid Hydrogen-Fueled Hybrid Electric Aircraft

Abstract The aviation industry is undergoing a significant transformation as it seeks to align with global sustainability goals, particularly the ambition to achieve net-zero carbon emissions by 2050. Conventional aircraft, which rely on fossil fuels, are responsible for a substantial portion of global greenhouse gas emissions. As a result, there is an urgent need to develop alternative propulsion systems that minimize carbon footprints. Hybrid electric aircraft, powered by a combination of hydrogen, fuel cells, and battery systems, represent one of the most promising pathways toward sustainable aviation. Hydrogen is a clean energy carrier with the potential to significantly reduce emissions. However, the integration of these technologies presents significant thermal management challenges, which must be addressed to ensure safe and efficient operation. This study presents the modeling and simulation of a thermal management system (TMS) designed for hybrid electric aircraft powered by liquid hydrogen (LH2), fuel cells, and battery systems. It addresses these challenges by developing a TMS model that efficiently regulates the temperature of the fuel cells, batteries, and associated electronic components while maintaining overall system performance. The proposed system employs a multi-loop architecture, combining active and passive cooling techniques, such as liquid cooling and heat exchangers with liquid hydrogen as heat sink which is typically stored in a tank at cryogenic temperatures (∼20 K). The effectiveness of the TMS is evaluated under a single mission scenario. A pipe diameter of 45 mm was found optimal, balancing pump power and system weight. Coolant mass flow reduces by 48.67% from take-off to cruise, with the fuel cell route dominating at 78.15% (take-off) and 94.43% (cruise).