Characterization of a Lean Premixed Prevaporized Combustor with Conventional and Sustainable Fuel

This study quantifies the behavior of a lean premixed prevaporized combustor operating at elevated temperatures and pressures, using both conventional and sustainable aviation fuel. Three different fuel compositions, 100% Jet-A, 100% hydrogenated esters and fatty acids (HEFA), and a 50/50 volumetric blend, are tested at various equivalence ratios and air preheat temperatures. Mie scattering is used to examine the liquid fuel spray pattern in the combustor; phase Doppler particle analysis is used for droplet sizing; 10-kHz OH planar laser induced fluorescence is used to determine the flame surface distribution and to examine the lean blowoff process. Experimental data show that the pure HEFA fuel had smaller droplets and lower fuel penetration depths because of favorable physical properties, but did not otherwise affect the combustor behavior. Despite the differences in fuel spray, the flame surface density fields are similar across fuels. Furthermore, the lean blowoff Damköhler vs Reynolds-number behavior is the same for all fuels within experimental uncertainty. These results demonstrate promising fuel flexibility for low-emission lean premixed prevaporized combustor technologies.