Explosion dynamics and sensitivity analysis of blended LPG/DME clean fuel promoted by H₂ in a confined elongated space

The involvement of highly chemically reactive H₂ greatly increases the fuel explosion risk. In order to reveal the elevated explosion risk of LPG/DME blended gas due to the participation of H₂, the explosion-promoting dynamics of H₂ and its sensitivity characteristics are investigated based on a combination method of numerical simulation, experimental verification and theoretical analysis. The results show that the participation of H₂ increases the explosion overpressure and the shockwave propagation velocity by 147.9% and 90% respectively to the greatest extent. The explosion temperature shows five typical combustion stages, with the participation of H₂, the maximum temperature rise range of the shock wave adiabatic compression heating period and the combustion period is significantly increased, the adiabatic holding time is prolonged, the peak flame temperature is increased, and the flame propagation velocity is also significantly improved. The addition of H₂ causes the relative distance between the explosion shock wave and the flame front first increases, then decreases and then increases in the shape of “half-morning glory”. The number and sensitivity coefficients of the new explosion-promoting elementary reactions brought by H₂ are larger than that of the new explosion-inhibiting elementary reactions, which explains and confirms the explosion-promoting nature of H₂ in terms of the reaction mechanism.