Abstract: In order to study the influence of explosion relief on the gas explosion parameters in bend pipe, the changing law of explo- sion pressure with opening states was analyzed based on experi- mental test and numerical simulation. The experimental results show that the maximum explosion pressure is 0.437 MPa at 4.727 m inside the elbow of the closed pipeline, and the maximum explosion pressure reduces by 13.5% after venting. The maximum influence point of the change of the position of the outlet on the explosion pressure is located at 4.772 m in the bend. When the ex- plosion vent is located at 4.757 m, the maximum explosion pressure reduces by 9.84% at 4.8 m, including the obvious discharge effect of the induced precursor wave in the early explosion stage and the weakening discharge effect due to the superposition and pressure accumulation of shock wave reflection in the later explosion stage. With the increase of the distance between the position of the venting and the ignition point, the maximum explosion pressure at the bend decreases then increases, showing the Gauss one-dimensional functions. The maximum explosion pressure in the bend pipe with relief explosion is lower than that of closed pipeline when it locates after 4.786 m. The maximum explosion pressure in the bend pipe which follows a exponential function that decreases monotonically with the increase of the distance between the ignition source.

Key words: gas explosion, explosion pressure, explosion relief, numerical simulation, pipe with 90° bend