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Three Dimensional Radiative Ignition and Flame Spread Over Thin Cellulose Fuels.


pdf icon Three Dimensional Radiative Ignition and Flame Spread Over Thin Cellulose Fuels. (309 K)
Olson, S. L.; Kashiwagi, T.

NISTIR 6242; October 1998.

National Institute of Standards and Technology. Annual Conference on Fire Research: Book of Abstracts. November 2-5, 1998, Gaithersburg, MD, Beall, K. A., Editor(s), 67-68 pp, 1998.

Available from:

National Technical Information Service
Order number: PB99-102519

Keywords:

fire research; fire science; fire suppression; cellulosic fuels; ignition; flame spread; space shuttle; lamps

Abstract:

Radiative ignition and transition to flame spread over thin cellulose fuel samples was studied aboard the USMP-3 STS-75 Space Shuttle mission in February and March of 1996, using the RITSI hardware. A focused beam from a tungsten/halogen lamp was used to ignite the center of the fuel sample while fan-drawn air flow was varied from 0 to 6.5 cm/s. Non-piloted radiative ignition of the paper in air was found to occur more easily in cicrogravity than in normal gravity. Ignition of the sample was achieved under all conditions studied, with transition to flame spread occurring for all but the quienscent flow condition. After ignition, the flame spread only upstream, in a fan-shaped pattern. The fan angle increased with increasing external flow from zero angle (tunneling flame spread) at the limiting 0.5 cm/s external air flow, to 90 degrees (semicircular flame spread) for external flows at and above 5 cm/s. The downstream flame is inhibited due to the 'oxygen shadow' of the upstream flame, despite the convective heating from the upstream flame. Only after the upstream flame spread was complete could downstream flame spread occur.