Local Flame Propagation Characteristics in a Rectangular Chamber

摘要

Experimental investigations were performed to examine the characteristics of propagating flame fronts around multiple bars within a rectangular chamber. The explosion chamber is 400 mm in height, 700×700 mm~2 in cross-section and has a large top-venting area, A_v, of 700×210 mm2. This results in a value of 0.44 for A_v/V~(2/3) and a L/D value of 0.57. The multiple obstacles of length 700 mm with blockage ratios of 30 % and 43 % were placed within the chamber. Temporally resolved flame front images were recorded by a high speed video camera to investigate the interaction between the propagating flame and the obstacles. Results showed that the flame propagation speeds before the flame impinges onto the obstacle almost equal to the laminar burning velocity. As the propagating flame impinged on the obstacle, the central region of flame began to become concave, this resulted in the flame deceleration in the region. As the flame interacted with the modified flow filed generated behind the central obstacle, the pdfs were extensively distributed toward higher speeds.