EXPERIMENTAL STUDY OF THE INFLUENCE OF OBSTACLES AND PARTIAL CONFINEMENT ON FLAME PROPAGATION. PART II
To gain more insight into the characteristics of flame propagation in obstacle environments an experimental investigation has been performed. An obstacle array consisting of horizontal tubes parallel to each other near the ground was used. To study the effect of partial confinement a plate was mounted parallel to the ground over the obstacles. The tests were performed on two different scales. The influence of such parameters as the gap between obstacles and ground, obstacle separation, top plate height, porosity of a perforated top plate, gas reactivity and the location of the ignition source on flame propagation was studied. Maximum flame speeds up to 310 ms**-1 in the case of central ignition were found when the obstacles were partially confined, whereas in the absence of confinement maximum flame speeds of about 50 ms**-1 were encountered. This demonstrates the overriding effect of partial confinement in vapour cloud explosions. As the experiments were performed on two different scales, scaling of flame speed results from vapour cloud explosion experiments could be studied at the same time. This showed that simple scaling should be possible as long as flame propagation is dominated by molecular transport processes. Blast measurements performed on a large scale revealed a stronger than acoustic decay close to the non-spherically symmetric obstacle arrays. Within the array a maximum overpressure of 70 kPa (central ignition) was measured.
Bibliographic Reference: EUR 9541 EN (1985) MF, PART II, 82 P., BFR 150, BLOW-UP COPY BFR 410, EUROFFICE, LUXEMBOURG, POB 1003
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Record Number: 1989123095700 / Last updated on: 1987-01-01
Available languages: en