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I A1-IA 5

Experiment ID IA1-IA5 (5 tests)
Short Description Partial confinement – simulating a “lane” – consisting of 2 parallel walls at a distance of 3 m with a length of 12 m and a height of 3 m. The whole volume has been filled with H2/air mixture, enclosed within a very thin PE-foil. At one of the front sides of this lane a container (length 3 m, cross section 1.5x1.5 m2) with a variable opening (vent opening ratios 0.1 and 0.3, i.e. ratio of areas: opening area/front side area of container) has been installed, containing the same mixture as in the lane. The mixture has been ignited at the rear side of the container. The flame jet emerging out of the container ignites the mixture within the lane.
What phenomena were studied The background for doing this type of tests has been the idea, that the phenomenon of DDT in geometrically similar arrangements could be scaled by means of the detonation cell width. Within a test set-up similar to that described above, but with dimensions being a factor of 3 smaller, Battelle/Germany succeeded in getting DDT for stoichiometric H2/air mixtures, but no DDT with other concentrations. If it is assumed that the effect can be scaled linearly with the detonation cell size, then in a similar test set-up with dimensions, which were 3 times larger, the limit for DDT (go/no go) should be in mixtures with H2 content of 20.5 vol% according to the U-shaped relation between detonation cell size and fuel concentration or equivalence ratio.
What phenomena / effects can be studied Geometrically similar facilities of the type investigated here, can be linearly scaled with detonation cell size with respect to DDT.
Instrumentation Gaschromatographic analysis of mixture homogeneity. Accuracy of H2 : ± 0.3 vol%. 2 piezoresistive pressure transducers within container. 2 sets of pressure transducers within the lane floor (8 piezoresistive and 8 piezoelectric transducers). 3 high speed cameras (2 with view from above, 1 with horizontal view into the lane).
Test variables Vent opening ratio of container front side: 0.1 and 0.3; hydrogen concentration (vol%): 20.2 – 22.5
Data description / Data completeness Film recordings (16 mm) available; pressure/time histories as hardcopies
Data availability Publicly accessible
Source of data / Reference Fh-ICT-report (Oct.1984): Versuche zur Freistrahlzündung partiell verdämmter Wasserstoff/Luft- Gemische im Hinblick auf die Skalierbarkeit des Übergangs Deflagration/Detonation
Why were chosen Of relevance for realistic scenario: ignition in closed room with venting (garage for example) and subsequent flame jet ignition of partially confined cloud outside (some sort of a lane)
Relevance to the project purposes Important for the establishment of criteria for DDT, especially scaling of DDT- phenomena
Experimental data
Results of simulations
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Page last modified on December 22, 2008, at 01:50 PM