It is normal practice to use centrally positioned vents or single vents in most experimental work and in the application of explosion venting in industry. This work seeks to investigate the influence of non-central and multiple distributed vents on the explosion overpressure. A 10L cylindrical vessel of 460mm length and 162mm diameter (L/D=2.8) was used for vented explosion with free venting (without a vent cover). Three different vent coefficient (Kv) were investigated, Kv, 3.6, 5.4 and 10.9 for both non-central and 4 hole vents. 10% methane-air and 7.5% ethylene-air mixtures were investigated to determine the influence of the mixture reactivity. The position of the spark ignition was in the centre of the end flange opposite the vent. It was shown for the non-central vent that the flame speed upstream of the vent was lower than for a central vent and this reduced the mass flow through the vent, which reduced the overpressure and reducing the external explosion due to the lower exit velocity of the unburnt gas and hence lower external turbulence. The external flame jets downstream of the vent was influenced by the increase in characteristic length scale of the vent, which was changed by increasing the number of vents.
展开▼
机译：在大多数实验工作中以及工业上的爆炸通风应用中，通常使用中心通风孔或单个通风孔。这项工作旨在调查非中央和多个分布式排气孔对爆炸超压的影响。使用长度为460mm，直径为162mm（L / D = 2.8）的10L圆柱形容器进行带自由排气的排气爆炸（无排气盖）。研究了三种不同的排气孔系数（Kv），分别是非中心排气孔和4孔排气孔的Kv，3.6、5.4和10.9。研究了10％的甲烷-空气和7.5％的乙烯-空气混合物，以确定混合物反应性的影响。火花点火的位置在与排气孔相对的端部凸缘的中心。对于非中央通风口，表明通风口上游的火焰速度低于中央通风口，这减少了通过通风口的质量流量，这降低了过压并由于较低的出口速度降低了外部爆炸。未燃烧的气体，从而降低了外部湍流。排气孔下游的外部火焰喷射受到排气孔特征长度尺度的增加的影响，而长度尺度的增加会随着排气孔数量的增加而改变。
展开▼
