Publication

Abstract : The ability of supercritical carbon dioxide (sCO2) oxy-combustion power cycles like Allam cycle to capture 99% of the carbon produced in combustion started gaining attraction nowadays. The Allam cycle works at extreme pressure conditions (200–300 bar), and it substantially increases the efficiency. To promote and accelerate the growth and development of combustors for such cycles, a study on kinetic models using sCO2 as diluent has to be conducted by exposing it to extreme operating conditions such as higher pressures (300 bar) and high inlet temperatures (1000 K) along with different levels of CO2 dilution. The paper focuses on identifying the effect of supercritical CO2 in a combustor where the fuel used is methane by analyzing its impact on parameters such as temperature and ignition delay time (IDT) for the CH4–O2–CO2 mixture with variation in CO2 dilution. The software ANSYS Chemkin-Pro is used for the initial simulations where two zero-dimensional models are analyzed with the above said conditions of pressure and temperature for various mixture ratios of CH4–O2–CO2. Saudi Aramco 2.0 mechanism is used for Chemkin simulations. Finally, computational fluid dynamics (CFD) simulation of combustor is done in ANSYS Fluent by importing GRI-Mech 3.0 and the reduced Aramco 2.0 mechanisms and compared the results for different CO2 dilutions.