Investigation of the Effects of Hydrogen Addition on Explosion Characteristics and Pressure Fluctuations of Ethyl Acetate

This study systematically explored the characteristics of explosion and pressure fluctuations of ethyl acetate (EA)/hydrogen (H2)/air mixtures under different initial pressures (1–3 bar), H2 fractions (4%, 8%, 12%), and equivalence ratios of EA (0.5–1.4). The flame images indicated that a higher pressure, a higher H2 fraction, and a higher equivalence ratio could cause flame instability. An analysis of the dimensionless growth rate indicated that the flame instability was impacted by both thermal diffusion and hydrodynamic effects. The results also indicated that a higher initial pressure or H2 fraction could accelerate the combustion reaction and increase the explosion pressure and deflagration index. The maximum values were observed at 21.841 bar and 184.153 bar·m/s. However, their effects on explosion duration and heat release characteristics differed between lean and rich mixtures. Additionally, this study examined pressure fluctuations in both the time and frequency domains. The findings indicated a strong correlation between pressure fluctuation and flame instability. Modifying the H2 fraction and equivalence ratio to enhance flame stability proved effective in reducing pressure fluctuation amplitude. This study offers guidance for evaluating explosion risks associated with EA/H2/air mixtures and for designing related combustion devices.