Assessing the effect of composition on dielectric constant of sustainable aviation fuel

• Dielectric constants for 35 individual molecules and 6 SAFs are compared to 172 jet fuels. • Hydrocarbon types contribute differently to the Clausius-Mossotti relationship. • 100% drop-in capacitance-based FQIS-compatible SAF compositions need aromatics. • Two blending rules were validated for the dielectric constant of jet fuel range hydrocarbons. One of the challenges in developing 100% sustainable aviation fuels is the effect of synthetic blend components on the dielectric constant. Modern aircraft often employ capacitance-based gauging systems that rely on the dielectric constant of the fuel onboard to determine fuel quantity. Aircraft manufacturers have expressed concern over inaccuracies in fuel gauging attributable to variances in the dielectric constant between conventional jet fuels and 100% paraffinic sustainable aviation fuel. In our study, dielectric constant and density data were gathered from 172 conventional jet fuel samples to establish a baseline “experience range.” Subsequently, thirty-five individual hydrocarbon molecules from the jet fuel range and nine fuels were acquired, characterized, and reported herein according to the Clausius-Mossotti relationship. Our findings indicate that different hydrocarbon group types exert varying effects on the Clausius-Mossotti relationship. To align with the established experience range for both the dielectric constant and the Clausius-Mossotti relationship, it appears that 100% drop-in SAF will need to incorporate some aromatic compounds. Finally, we explored two blending rules for the dielectric constant of jet fuel range hydrocarbons and achieved excellent coefficients of determination (R 2 values of 0.9942 and 0.9983, respectively).