Abstract: In order to understand the propagation law of dust explosions in bend ducts， variety of bend pipes were set up based on 1m³ explosion test system， including pipes with a 90-degree bend， S-shaped pipes， U-shaped pipes and long straight pipes. Corn starch was used as the explosion test sample. The overpressure development and flame propagation along the bend pipes were recorded by the computer and analyzed. For the established test rig， the results show that the explosion overpressure in the pipes shows a downward trend for the same dust concentration， but its attenuation rate at the bend part decreases. The attenuation rate of those four kinds of pipes is as follows:straight pipe>90-degree bend>S-bend>U-bend. Although the flame propagation velocity is continuously accelerated in the pipes， the bend hinders the flame propagation. The rate of flame propagation velocity rise in bend pipes is smaller than that in the straight pipes. The above research conclusions have reference and application value for the explosion proof design of the dust removal system.

Key words: U and S-shaped bend pipes, 90-degree bend pipes;dust explosion, explosion overpressure, flame propagation velocity