Flame spread-over thin paper samples in low-speed concurrent flow is experimentally investigated in a 5.18s drop tower. In the experiment, the oxygen molar percentage is varied from 30 % down to the flame extinction limits and the forced flow velocity from 5.29 cm Is down to the quenching limits. Motion pictures are taken to observe flame shape, color, size, and spread rates. These quantities are compared with a theoretical model describing concurrent flame spread over thin solids in low-speed flows. The paper also discusses the similarity and difference between concurrent-flow and opposed-flow flame spread in microgravity and between low-speed and high-speed concurrent-flow flame spread. Finally the limitations of using a drop tower for flame spread research is assessed.
Grayson, G., Sacksteder, K.R., Ferkul, P.V., T'ien, J.S., Flame Spreading Over a Thin Solid in Low-Speed Concurrent Flow - Drop Tower Experimental Results and Comparison with Theory, Microgravity Science Technology, Hanser Publisher, Munich, Germany, Vol., VII/2, pp. 187-195, July 1994.