| Abstract | In 2017/18, the NRC undertook biofuel contrail flight research from a number of jet transport aircraft and jet fuels, including petroleum JetA1, JP-5, HEFA and ethanol-derived ATJ biofuels. The flight contrail data, consisting of derived ice particle number, size, spherical mass, and the FSSP-100 optical properties of effective size, extinction coefficient, optical depth and laterally-integrated optical depth, was obtained and compared for JetA1, JP-5 and biofuels (43% HEFA-SPK blend with Jet A1 and 92% ethanol-derived ATJ-SPK blend with aromatics). Contrail conditions covered sublimating to persistent. Contrail properties were compared with aerosol and non-volatile particulate emissions, and with previous soot modeling of young contrails. Results showed progressive reductions in persistent contrail ice particle number with biofuel blend percentage, almost log-linear reductions with non-volatile aerosol emissions, a slight increase in ice particle size with 92% ATJ-SPK. The lateral integrands of optical depth showed 30-50% reductions for the 92% blend ATJ-SPK, compared to Jet A1. |
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