Characterization and microscopic mechanism analysis of urea-modified dry water powders for inhibiting dust explosion of aluminum‑magnesium alloys

Abstract

Aluminum‑magnesium alloy has been widely used in electronics, automotive, aerospace and other fields due to its advantages of high strength, low density and good heat dissipation. The accompanying aluminum‑magnesium alloy dust explosion accidents have been increasing. In order to prevent the occurrence of this accident, a new type of urea-modified dry water (UMDW) powder was prepared by using urea solution as a core material, which was applied to the suppression of aluminum‑magnesium alloy dust explosion. Experiments on dust explosion pressure and flame propagation characteristics were carried out, and the explosion products were analyzed by XRD, XPS and other testing methods. The results showed that after the addition of 40 wt% UMDW, the maximum explosion pressure of aluminum‑magnesium alloy dust decreased from 0.621 MPa to 0.093 MPa, with a decrease of 85.02 %; (dp/dt)_max decreased from 11.6 MPa/s to 1.29 MPa/s, with a decrease of 88.88 %; the flame propagation height decreased from 600 mm to 269.54 mm. The flame propagation height decreased from 600 mm to 269.54 mm, and the flame propagation speed decreased from 5.51 m/s to 0.7 m/s. Chemkin pro was used to perform temperature sensitivity analysis to find out the key reaction steps of UMDW on the explosion suppression of aluminum and magnesium alloys dust, and to reveal its microscopic and efficient explosion suppression mechanism.