Additive could keep jet fuel from exploding in crashes

Regular untreated jet fuel (top) and fuel with the polymer additive (bottom)(Credit: Caltech/JPL)

Living through an airliner crash involves more than just surviving the initial impact – many people are also killed by the flames and smoke that follow when the jet fuel ignites. Researchers at Caltech, however, are trying to minimize the chances of that second part happening. They've developed an additive that helps reduce the intensity of postimpact fuel fires.

In regular jet engines, fuel is mixed with compressed air to form a fine mist that is then ignited with an electric spark, producing forward thrust. Unfortunately, that same mist easily combusts in the event of a crash, when it escapes from the combustion chamber.

To keep that from happening, a team led by Prof. Julia Kornfield developed a polymer that can be added to jet fuel without affecting its performance or energy capacity. This polymer consists of long molecular chains known as a "megasupramolecules," which are joined end-to-end via Velcro-like chemical connectors at the end of each one.

These connectors pull apart to let the megasupramolecules separate, as the fuel/polymer mix is expelled from a fuel injection nozzle. This lets the fuel work as it normally does, temporarily forming into droplets that make up a mist. If that mist isn't ignited immediately, however, the connectors reconnect with one another as the droplets meet, causing the mist to coalesce back into a less flammable concentration.

Kornfield's colleague Ming-Hsin "Jeremy" Wei is now working on creating a reactor that could produce commercial-scale quantities of the polymer. He hopes to have it up and running in less than a year.

A paper on the research was published today in the journal Science. The flame-retardant qualities of the polymer are demonstrated in the video below.

Source: Caltech

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