Evaluation of Aircraft Environmental Control System Order Degree and Component Centrality

Air cycle systems (ACSs) are primarily used in aircraft environmental control systems (ECSs) to provide a suitable cabin temperature and pressure environment for passengers and avionics. It comprises heat exchangers, compressors, turbines, water separators, and various other components that are interconnected to form an information-transmission network. Traditional research on ACSs has focused primarily on their thermal performance. This study abstracted ACSs into network graphs based on their information-transmission characteristics, determined the weight of each information-transmission route using the fuel weight penalty method, calculated and compared the order degree of different ACSs using the structure entropy method, and measured the importance of each component using centrality for the first time. The results showed that the order degree of the ACSs gradually increased with an increase in the number of wheels in the air cycle machine (ACM), and ACSs with high-pressure water separation had a higher order degree under wet conditions than under dry conditions. Moreover, based on the centrality of each vertex in the graphs, the ACM and secondary heat exchanger in the ACS were fundamentally important and should be focused on during the system design. The methodology proposed in this study provides a theoretical basis for the evaluation of the ACS organizational structure and the design performance of components.