Study on the effect of pre-blended section ratio and hydrogen blended ratio on explosion dynamics of dimethyl ether-hydrogen blended gas

Abstract

To reveal the explosion risk of dimethyl ether-hydrogen blended gas in the process of hydrogen energy utilization, this paper studies the effects of different hydrogen blended ratios and pre-blended section ratios on the explosion characteristics of dimethyl ether-hydrogen blended gas. The results show that the maximum explosion overpressure decreases with the increase of hydrogen blended ratio in the rapid decay zone of overpressure hazard, and it is the smallest when the hydrogen blended ratio is 0.9. In the slow decay zone of overpressure hazard, the relative error of the peak overpressure at different hydrogen blended ratios is within 3 %, and the effect of hydrogen blended ratio on the explosive power is very limited. The overpressure in this zone is relatively small, but the propagation and impact distance is the largest. Shock waves under different pre-blended section ratios in the corresponding fuel-premixed zone are constantly accelerated in their propagation, resulting in the maximum explosion overpressure in their corresponding fuel-premixed zone showing an increasing evolutionary law. The maximum explosion overpressure under different pre-blended section ratios increases to a maximum in 1/4, 1/2, 3/4, and 4/4 of the pipe, respectively. The greater the proportion of premixed zone, the greater the peak overpressure, resulting in greater explosive power and hazard.