Study on Explosion Characteristics of Ammonia/Dimethyl Ether/Air with Different Mixed Compositions

Author：Zhang, Z. H., Zheng, K. X., Ning, X. Y., Wang, X. H., Wang, J.

Journal：Energy & Fuels

DOI:  10.1021/acs.energyfuels.3c01551

Keywords: laminar burning velocity, ignition delay-time, heat release rate, flame speed, performance-characteristics, dimethyl ether, high-pressure, ammonia, air, combustion, Energy & Fuels, Engineering

Abstract: 

The blend of ammonia (NH3) and dimethyl ether(DME)is a promising renewable and clean fuel. This work studies the basicexplosion characteristics of NH3/DME/air with varying equivalenceratios (from 0.6 to 1.8) and DME fractions (from 0.2 to 1). Threeessential parameters, i.e., explosion pressure (P (max)), explosion time (t (c)),and maximum pressure rise rate ((dP/dt)(max)), were experimentally obtained, and the heat lossduring the explosion was quantitatively analyzed. Besides, the heatrelease characteristics and critical flame radius of destabilizationin the explosion process were analyzed using the detailed NH3/DME reaction mechanism. The results showed that adding DME to themixture can significantly increase the P (max), increase the (dP/dt)(max), and shorten the t (c). The heat loss duringthe NH3/DME/air explosion mainly presents a negative correlationwith the explosion intensity, as reflected by (dP/dt)(max) and t (c). In addition, at stoichiometric ratios, the elementary reactionR12: H + OH + M = H2O + M contributes most to the totalheat release of the NH3/DME/air explosion, while the NH3- or DME-related reactions subdominate the total heat production.Adding DME reduces the critical flame radius, causing the flame toenter an unstable state earlier, which is mainly dominated by thehydrodynamic effect.