关键词: 热管理, 内循环, 图论, 网络动力学, 模态分析

Abstract: Introducing an internal circulation loop boosts aircraft thermal management system (TMS) heat sink efficiency. However, it cre-ates complex dynamics with flow-dependent response delays. TMS couples thermodynamic and fluid dynamic processes, featur-ing numerous interconnected nodes that exhibit high heterogeneity and complexity. Conventional modeling fails to capture these dynamics or analyze delay causes, hindering control design. This paper proposes a hierarchical (hydraulic-thermal) graph-based modeling method for internal loop TMS dynamics. It reveals delay mechanisms and quantifies delay zones across flow states. The results show that the fundamental cause of the delay effect is that the internal circulation alters the topological structure of system dynamics and adds positive feedback terms, and the larger the flow rate of the internal circulation, the slower the system response speed.

Key words: Thermal Management System, Internal Circulation, Graph Theory, Network Dynamic, Modal Analysis