Experimental study on the flame-dual field overpressure coupling evolution characteristics of LPG/DME blended gas explosion venting

To reveal the LPG/DME blended gas explosion venting flame -dual flow field overpressure evolution characteristics, a multi -gas explosion venting experimental platform was established in this paper. Blended gas concentrations with equivalent ratios of Phi = 0.8, 1.0, 1.2, 1.6, and 2.0 were selected to study the dynamic evolution of the venting flame and the overpressure propagation -risk mechanism. The results show that: The venting flame propagation speed first suddenly rose and then slowly fluctuated down along the axial direction. As the Phi increase, the maximum flame propagation speeds are 65.17 m/s, 164.38 m/s, 178.65 m/s, 122.55 m/s, and 75.66 m/s, respectively. With an increase in Phi > 1.0, the outfield of the flame gradually shifts from deflagration to diffusion combustion. The flame shape transforms from "jet" to "flaming cloud". Both external overpressure and internal overpressure increase at first and then decrease with the increase of 0. and due to the dilution effect of explosion venting concentration, the peak overpressure reaches a maximum of 150.94 kPa and 21.25 kPa, respectively. In all equivalent ranges, a secondary explosion is formed at Phi = 1.6 with an overpressure of 8.97 kPa, which more complicated the risk of overpressure in the explosion venting.