Impact of the blockage ratio and void fraction of porous obstacle on gas explosion characteristics in semi-confined channel.

This study conducted various explosion experiments under different porous obstacle conditions of blockage ratio (BR) and void fraction (Φ f). The impact of porous obstacle on flame propagation velocity (v) and peak overpressure (P op) were analyzed. The results indicate that an increase in the BR enhances explosion pressure near the blockage area for both porous and non-porous obstacles. However, it also increases the downstream pressure decline gradient. An increase in the Φ f weakens the hindrance of porous obstacle on the flame propagation, allowing more flame to pass through the internal void channels of obstacles, thus delaying the downstream pressure decay. Compared to non-porous obstacles, gas explosions disturbed by porous obstacles with both high BR (BR＞75%) and high Φ f (Φ f ＞0.55) exhibit a lower downstream pressure decline gradient and a longer positive pressure duration. As a result, the explosion can produce a broader range of destruction. • The impact of porous and non-porous obstacles on flames was compared. • The propagation stability of flame gradually reduces with an increasing BR. • Increasing BR results in the forward shift of the maximum P op point. • Increasing V f tends to delay downstream explosion pressure decline. • Porous obstacles can amplify the destructive range of explosion. [ABSTRACT FROM AUTHOR]