Abstract: In order to understand propagation mechanism of premixed flame, influence of multi-hole obstacles at different locations in semi-closed pipes on flame propagation was studied through experiments. Then, propagation process was recorded by high-speed cameras, and shape and dynamic changes of flame before and after passing through obstacles were analyzed. Meanwhile, its edges were detected by using boundary operator, pixels were calculated, and folds were measured. The results show that compared with cases without obstacles, multi-hole obstacles intensifies flame front folds, which therefore increases pixel value of its edge and shortens time to spread in pipes. In addition, it was found that the farther obstacles are away from ignition position, the more significant impact they will have on flame. And compared with cases of zero obstacle, when it is at 100 mm position, maximum transmission speed of flame is increased by 54%, transmission time is reduced by 76.2%, and flame edge pixel increased by 52.7%.

Key words: multi-hole obstacles, premixed flame, flame propagation speed, flame fold, image edge detection