Abstract: In order to study propagation characteristics of gas explosion shock waves and flame waves in pipelines with differently-shaped obstacles, Fluent software was used to simulate changes of overpressure and temperature during gas explosion, and effects of circular, square and rectangular obstacles on gas explosion shock waves and flame waves were systematically studied. The results show that peak pressure of gas explosion can reach 0.84 MPa when a square obstacle with a side length of 0.13 m exists in pipelines and explosion-proof facilities should be strengthened especially where there are square obstacles in actual roadways. For all obstacles of various shapes, increase of their sizes will lead to increase of peak explosion overpressure. For circular obstacles, peak temperature increases first and then decreases and its change range is small when blocking rate changes from less than 50% to more than 50%. Therefore, it can be inferred that peak temperature will change in different ways with a blocking rate of 50% as the boundary. As for square and circular obstacles, peak temperature will increase with an increase of blocking rate. It is also found that explosive flame waves will flow around different obstacles, indicating that obstacles will accelerate propagation of flame waves.

Key words: gas explosion, shock waves, numerical simulation, obstacles, obstruction rate