A Modeling Framework for Supercritical CO2 Power Systems in Aviation

This study focuses on developing and validating a supercritical carbon dioxide (sCO₂) Brayton cycle with an approach of individual component modelling using Simcenter Amesim. The aim is to validate the Amesim model with the behavior of the Sandia National Laboratories (SNL) loop and adapt it for use as a waste heat recovery (WHR) system in aircraft engines. First, the turbomachinery model is validated against known reference points from the SNL report. Using the Helmholtz equation of state and detailed pressure-ratio (PR) and efficiency maps for turbomachinery, the system tracks key temperature, pressure, and mass flow rate conditions across the simulation. Fluid properties are obtained using Coolprop. The test results closely matched the maps generated and remained within their defined operating ranges. Compressor performance showed only minor deviation from the reference map, confirming expected behavior. However, the turbine required additional polynomial fitting to better capture its performance trends. In summary, this work provides a comprehensive method for validating turbomachinery performance maps and establishes a foundation for its use in transient modeling. As aircrafts operate under continuously changing conditions, a single reference map cannot represent all flight regimes. The validation performed in this study enables to move forward with corrected maps to be reliably applied and evaluated under various off-design and transient scenarios in future.