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 (H-2) blended gas, the explosion propagation characteristics of DME/H-2 blended gas under different equivalence ratio (Phi) and hydrogen blended ratio (lambda) 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 Phi, and reach the maximum at Phi = 1.0. The effect of a little addition of H-2 on the explosion hazards of blended gas is small, but when lambda > 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 lambda. 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 H-2. Comprehensive analysis of the thermodynamic and chemical kinetic parameters of H-2, the chemical kinetic parameters of H-2 play a dominant role in the explosion risk of hydrogen-blended gases.