Abstract
In this work, experiments data from vented explosions tests using gasoline-air mixtures in a small, open square duct with a 90° bend were performed using high-speed camera. It is found that pressure history in the semi-confined space can be divided into four phases, i.e. constant volume explosion, effusive flow overpressure, disturbance explosion, vibration attenuation. The bend structure has an impact on the flame structure during the explosion. In the confined space, the flame transforms from sphere to brush-like shape. The transformation of flame shape in the pipe can be classified into six stages. When flame propagates to the bend structure, it bypasses the bend along the inner wall of the pipe. Flame velocity and flame front position can be divided into four stages: explosion initial stage, accelerated effusion stage, disturbance explosion stage, and energy attenuation stage. Both changes are consistent with changes in flame morphology.
