Effect of Different Explosion Relief Outlet Angles on Explosion Relief Efficiency in Confined Areas

In this paper, we study the effect of explosion pressure relief from different angles of outlet in confined areas under methane-air premixed gas with a methane volume concentration of 9.5%. Results showed that increasing the angle of explosion pressure relief outlet from 30 degrees to 150 degrees generates a subsequent change in the overpressure attenuation rate of the straight pipeline segment (range 19.51-33.96%). Notably, the explosion pressure relief efficiency is most significant under working conditions of 60 degrees-75 degrees, and the overpressure attenuation rate is 30.21%-33.96%. The overpressure attenuation rate of the straight pipeline exhibits a non-monotonic relationship with the explosion pressure relief outlet angles, while the overpressure peak is positively correlated with the explosion pressure relief outlet angle. Collectively, these results provide a theoretical basis to guide future designing of explosion pressure relief outlet angles in a restricted space.