Graph-Based Dynamic Modeling of a PAO Loop for Aircraft Thermal Management Systems

Advances in electrification of air vehicles have presented new challenges in managing highly transient, distributed heat loads from onboard high-power electronic systems. To address these challenges, system-level modeling is necessary that is both dynamically accurate and computationally tractable. While prior work has focused primarily on modeling the air cycle machine (ACM), far fewer studies have modeled and analyzed the dynamic behavior of refrigeration-based cooling loops in aircraft thermal management systems (TMS). This paper extends prior work by introducing a modular, graph-based modeling framework capable of automatically generating and simulating variable architecture TMS. A polyalphaolefin (PAO)-based cooling loop is modeled as a representative subsystem. Using the proposed system-graph generation method, multiple architectures are programmatically constructed and simulated to assess transient performance. This work establishes a foundation for automated architecture synthesis and graph model-based architecture optimization, supporting further work in system-level modeling, control, and optimization.