Computational Investigation of Centrifugal Compressors Operating with Air and Supercritical CO2

The increasing concentration of carbon dioxide (CO2) in the atmosphere has spurred the need for effective Carbon Capture, Storage, and Utilization (CCSU) technologies. Supercritical CO2 (sCO2) has emerged as a promising working fluid in CCSU applications due to its compactness and efficiency in transportation and power generation cycles. However, the highly nonlinear behavior of sCO2 near the critical point requires further research to enhance numerical design models. In this context, this study focuses on the fluid-structural interaction (FSI) in the analysis of centrifugal compressors used in CCSU applications. The use of sCO2 as a working fluid enables the construction of more compact and efficient components, but it also poses challenges related to aerodynamic loads resulting from FSI. Structural failure modes, modal analysis, and resonance conditions are critical to ensure safe and reliable operation of sCO2-based compressors. Three case studies are presented in this work, including a literature-based compressor and two cases with application in CCSU. Static and modal structural analyses are conducted, and new geometries for the compressors are proposed based on the findings. The results reveal that while aerodynamic loads had minimal influence on the static behavior of the literature-based and the first-stage compressors, they were a significant source of load and required detailed treatment in the case of the fourth-stage compressor.