Mitigating post-impact energy release from liquid fuels

Abstract

Impacts that target fuel depots, fuel tanker trucks or rail cars, or the fuel tanks of vehicles, in addn. to impacts that use a fully fueled vehicle as a weapon, inflict greater damage by rapidly releasing much of the energy content of the fuel. Here, high-performance polymers are used to inhibit misting of fuel following impact to mitigate fuel explosion/conflagration. The approach is complementary to strategies that modify materials of construction of vehicles or buildings. Polymers added to fuel can mitigate impact-induced damage even when it is not possible to retrofit existing equipment or structures. Mist control polymers are complementary to approaches that provide fire retardant when impact is detected. Mist control polymers dissolved in fuel function through their innate response to rapid elongational deformation and do not require sensors or control devices to activate their response. The present polymers overcome prior obstacles to mist control fuel additives: 1) they do not degrade during transport of fuel through pumps and pipelines; 2) they remain sol. at low temps. (down to the f.p. of kerosene); 3) they are compatible with necessary fuel processing (filtering and dewatering); and 4) they burn in unmodified engines without measurably affecting power output or fuel efficiency. This combination of attributes was guided by theor. predictions of the mol. structure and concn. range in which end-to-end assocn. of polymers could produce a significant population of supramols. having mol. wt. greater than 5 Mg/mol, referred to as "megasupramols." This talk will summarize the theor. basis for the mol. design, the synthetic route to the polymers and characterization of their mol. structure, their rheol. properties in shear flow, and their performance in various fuel tests, including qual. observations regarding post impact misting, ignition and flame propagation.