Large-Scale Experiments on the Transmission of Fuel-Air Detonations from Two-Dimensional Channels

Abstract

Results of large-scale experiments on the transmission of hydrogen-air and ethylene-air detonations from a twodimensional channel into a large volume are reported. These data confirm the surprising observations of Liu et al who reported recent laboratory scale results which indicate that successful transmission of a detonation emerging from a rectangular orifice with a large aspect ratio L/W > 5, requires that the minimum width of the channel need be only about three detonation cell diameters, i.e., Wr ~ 3\. These results are surprising in view of the previous findings of Soloukhin and Edwards, where for square channels (L/W = 1), they observed that Wc ~ 10X. The apparatus for the largescale experiments consisted of a two-dimensional confined channel (1.83-m wide x 2.44-m long) with a variable width orifice, to the end of which was attached an inflated polyethylene bag of much larger dimensions to provide an unconfined environment for detonation transmission. Observations were made with high-speed cinematography and with smoked foils to measure the detonation cell size. Our results indicate that a minimum channel width of 3 is required for successful transmission from channels whose aspect ratios varied from 34 to 8. For channel asoect ratios of lass