Towards DNS of spray flame stabilization processes with Sustainable Aviation Fuels

Concern for emission reduction and energy security have motivated the development of new cost-effective alternative sustainable aviation fuels (SAFs). Drop-in SAFs are beneficial because they are made from renewable biomass and waste resources and do not require engine modifications for use in current aviation engines. However, any new fuel must characteristically match commercial Jet-A (or A2) fuel in order to meet the criteria for drop-in SAFs. Combustion characteristics are of particular concern when comparing a new fuel with Jet-A. Therefore, a fundamental understanding of the differences in combustion dynamics of new fuels is necessary to identify the impact of SAFs on current combustors. The objective of our research is to perform Direct Numerical Simulations (DNS) of spray flames under gas turbine cruise operating conditions (high pressure and temperature). Specifically, flame stabilization dynamics will be investigated using a jet flame configuration at representative thermodynamic conditions of the central recirculation zone (CRZ) in a swirl-stabilized combustor. The simulations will be performed using PeleLMeX, the low-Mach solver of the Pele suite. Lagrangian multi-phase modeling will capture the liquid spray injection and Adaptive Mesh Refinement (AMR) will allow for higher resolutions in targeted regions of the domain. The proposed DNS configurations will closely follow laboratory experiments performed at Sandia National Laboratories Combustion Research Facility. Two different SAFs (C1 and C9) will be compared with the reference Jet-A fuel. The impact on flame stabilization dynamics from 'turbulence-chemistry' interactions and low-temperature chemistry dependency on fuel properties are investigated.