Dr. Ashvin Hosangadi will be presenting at the ASME 2018 Turbomachinery Technical Conference & Exposition in Oslo, Norway. The presentation is titled: “Numerical Simulations of CO2 Compressors at Near-Critical and Sub-Critical Inlet Conditions.”
Monday, June 11, 2018, 14:00 PM-15:30 PM
Supercritical CO2 (SCO2) power cycles take advantage of liquid-like density of CO2 at supercritical pressures to reduce the power required by compressors and improve system efficiency. This results in compact turbomachinery rotating at very high speeds that operate near the critical point (304.12K, 7.37 MPa. However large variations in properties near the critical point make it difficult to design these compressors for stable and efficient operation over a wide range of full-load to part-load operating conditions; rapid density variations can potentially shift the compressor from a stable point to stall or choke for a fixed mass flow leading to potentially damaging unsteady dynamics.
In this paper, we will present an advanced real-fluid numerical framework for trans-critical CO2 spanning both the supercritical and sub-critical regime near the critical point. This framework has been implemented within the CRUNCH CFD® tool that has been extensively validated for near critical conditions. The numerical algorithm has specialized implicit integration methodology that allow sharp variations of thermodynamic derivatives near the critical point to be modeled faithfully. It also features advanced preconditioning of the time derivative that permits efficient treatment of numerical stiffness and results in accurate performance predictions near the critical point.