Influence of equivalence ratio and H₂ blended ratio on explosion propagation characteristics of DME/H₂ blended gas in closed narrow space

To reveal the explosion risk and propagation law of dimethyl ether (DME)/hydrogen (H₂) blended gas, the explosion propagation characteristics of DME/H₂ blended gas under different equivalence ratio (Φ) and hydrogen blended ratio (λ) was investigated based on experimental research and theoretical analysis. The results show that the peak overpressure (P_p), the peak pressure rise rate (dP/dt)_p and the peak shock wave propagation velocity (V_p) show an increasing and then decreasing trend with the increase of Φ, and reach the maximum at Φ = 1.0. The effect of a little addition of H₂ on the explosion hazards of blended gas is small, but when λ > 10%, the explosion hazards increase significantly. The magnitude of increase of P_p, (dP/dt)_p and V_p is different with the increase of λ. Compared with the enhancement effect on P_p and (dP/dt)_p, the enhancement effect on V_p is more obvious with the continuous blend of H₂. Comprehensive analysis of the thermodynamic and chemical kinetic parameters of H₂, the chemical kinetic parameters of H₂ play a dominant role in the explosion risk of hydrogen-blended gases.