Joshua Heyne, Ph.D., and Jamie Ervin, Ph.D.
Mechanical and Aerospace Engineering
As efforts continue to fight climate change by transitioning energy sources away from fossil fuels and towards renewable alternative, the commercial aviation sector finds itself at danger of falling behind in emissions reductions. To combat this, the best term opportunity to reduce the industry’s contribution to greenhouse gas emissions has been identified as sustainable aviation fuel, or SAF, derived from renewable feedstocks like agricultural waste or used cooking oil. Currently, SAF is regulated to a 50%v blending limit with conventional petroleum-based fuel to maintain certain jet fuel properties, including material compatibility with elastomer o-ring seals. When these seals come in contact with conventional fuels, they absorb fuel and swell, creating a tight seal at junctions in fuel systems. O-rings have been found to not absorb SAF as proficiently due to low aromatic content, which is also known to contribute to sooting (and, consequently, higher emissions) during combustion. Thus, it is desirable to develop SAF that can induce sufficient o-ring swell while limiting aromatic content as much as possible. To make progress towards 100% drop-in compatible SAF, this study reviews relevant literature on the subject to inform experimental methods and designs. Optical dilatometry measurements, featuring a updated heated method, for seal swell are analyzed alongside the steric effects, molar volume, and density of a number of potential aviation hydrocarbons covering multiple hydrocarbon classes. Additionally, a linear volumetric blending rule is examined for this property and is used to develop a simple model for SAF blend property predictions centered around o-ring swell. The data gathered and property relationships identified in this study will aid in the advancement of SAF towards the 100% drop-in approval needed to meet industry and government goals for decreasing GHG emissions.
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Aerospace Engineering | Mechanical Engineering
Faulhaber, Conor J., "Elastomer O-Ring Seal Swell Measurements for Sustainable Aviation Fuel Material Compatibility" (2022). Honors Theses. 384.