A Reduced Order Model Approach Based on Progress Variables for Simulation of Oxycombustion in the Allam-Fetvedt Cycle

The Allam-Fetvedt Cycle (AFC), which is designed to allow straightforward integration of baseload electricity generation from conventional and alternative fuels with Carbon Capture Utilization and Storage (CCUS) is based on oxycombustion in supercritical carbon dioxide (sCO2). Accurate simulation of oxycombustion under supercritical conditions requires the use of a real gas equation of state such as the Soave-Redlich-Kwong (SRK) equation as well as correlations for transport properties. Simulations of reacting flow in sCO2 are extremely computationally intensive, due to (1) the computational expense of using the SRK equation of state and transport property correlations, (2) the need to use reduced time steps to ensure stability, and (3) the use of compressible flow formulations, even at relatively low Mach numbers. Previous work simulated a model combustor featuring injection of CH4 mixing with and reacting with O2 in the sCO2 environment. Further exploration of the parameter space requires creation of more efficient computational methods. The current work details the development of a reduced-order model allowing for lower computational cost by projecting the thermochemical state onto a lower dimensional manifold is explored in the new simulations.