Experimental study on explosion characteristics of DME-blended LPG mixtures in a closed vessel

Experiments were performed to study the explosion characteristics of DME-blended LPG mixtures with different DME contents and equivalence ratios using a closed vessel. The maximum explosion pressure (P_max), the maximum rate of pressure rise (dP/dt)_max and the propagation velocity of shock wave (v) were investigated. The results indicated that both the peak overpressure and peak rate of pressure rise were raised with increasing DME content, reaching peak values at the equivalence ratio of 1.2. Furthermore, it was found that slight incorporation of DME had a small effect on the explosion hazard, but as the ratio of DME to LPG/DME mixture exceeded 30%, the explosion hazard would increase dramatically. The propagation of the shock wave behind the obstacle was divided into three stages in this paper: initial acceleration, stable acceleration and decaying. In the propagation process, P_max, (dP/dt)_max and v first increased and then decreased along the pipeline, and the peak values often appeared in the stable acceleration stage. The peak overpressure and the maximum value of v also appeared in the same location approximately, indicating that the occurrence of maximum overpressure risk was often accompanied with the appearance of the most severe dynamic evolution.