Computational Modeling of Hydrogen and Hydrogen-Methane Fuel Combustors for Gas Turbine Engine Applications

Abstract Related to the Sustainable Aviation Programs, focused on technologies to achieve some ambitious decarbonization goals for aircraft engines, research and development efforts into using alternative fuels, such as Sustainable Aviation Fuel (SAF) and Hydrogen. In relation to these efforts, this proposed study will focus on using Hydrogen and Hydrogen fuel blends in aircraft engine combustor to study the impact of reducing CO2 and NOx levels at typical operating conditions. Along with other SAF, Hydrogen is one of the most promising fuels for the Aviation industry to reduce CO2 levels significantly. However, NOx emissions are a bigger challenge in a Hydrogen-Air combustion system. Understanding the NOx emissions and its levels along with the temperature distribution in the combustor becomes even more challenging with Hydrogen as the primary fuel. Numerical simulations of combustion, with appropriate representation of chemical kinetics is expected to provide more insights about the temperature distribution and NOx emissions, thus aiding better combustor designs. At the present time, limited computational studies are underway in the gas turbine community. In this paper, multiple computational fluid dynamics (CFD) analyses have been completed by varying the combinations of mass fraction of Hydrogen and Methane in the fuel mixture for a NASA published public domain gas turbine combustor geometry under two different fuel flow conditions. All the previous calculations were for non-reacting cases, primarily to study the fuel-air mixing characteristics. The Hydrogen percentage in the mixture was varied from 0 to 100% (all Methane to fully Hydrogen) in steps of 25%. In this particular study, reacting flow simulations were performed for a pure Hydrogen and 50% H2-50% CH4 mixture and are presented and discussed. Converge CFD software was utilized for all the reacting flow calculations using the referenced NASA combustor geometry under combustor inlet conditions at the design point. The numerical results are presented and discussed with the available experimental data for the combustion performance and emissions.