Energy conservation optimization based on RSM-NPSO and safety boundary research of hydrogen engine thermal management system

Hydrogen propulsion is a promising pathway for achieving zero-emission aviation. The thermal management system (TMS) is essential in extending the operational envelope of hydrogen engines. However, the complex thermal regulation mechanisms of TMS can significantly increase operational costs and introduce safety risks. To address these challenges, this study proposes a hybrid strategy integrating response surface methodology with nonlinear adaptive-weight particle swarm optimization (RSM-NPSO) framework. First, an integrated model of the hydrogen engine and its TMS is established. The RSM is employed to quantify the significance of key TMS parameters, and subsequently, the NPSO is applied to optimize energy conservation performance. Finally, the impact of TMS performance deviations on engine safety is examined, enabling the definition of precise safety limits. Results indicate that collectively optimizing heat exchanger power, turbomachinery efficiency, heat transfer medium mass flow, and multi-branch mass flow ratio reduces fuel consumption by 14.54 % and transport cost by 11.74 %. The proposed NPSO outperforms conventional particle swarm optimization method, achieving a 71.37 % reduction in computational time and an average improvement of 22.5s in specific impulse. Additionally, the simulations reveal that safety boundaries of TMS vary considerably across operating points, yielding distinct safety power ranges for each heat exchanger within the flight envelope.