Impacts of hydrogen fraction and equivalence ratio on the explosion characteristics of ethanol/hydrogen mixtures

With the anticipated widespread integration of biofuels and hydrogen fuels within the future energy landscape, the potential explosion hazards after their release within confined spaces under the atmospheric are deserving of heightened attention. The present work takes the mixtures of ethanol and hydrogen as the objects and experimentally studies the impacts of hydrogen fraction and equivalence ratio on the explosion characteristics in a constant-volume explosion vessel at 0.10 MPa and 400 K. The data reveals that an increase in the hydrogen fraction leads to a rise in the maximum explosion pressure during lean explosions but causes a decrease during rich explosions. Nonetheless, the duration of the explosion decreases with the increase of hydrogen fraction in all the explosions. In consideration of explosion pressure, the maximum pressure rise is found to be exponential in relation to the maximum explosion pressure. However, the confidence level diminishes significantly with an increase in the hydrogen fraction. Conversely, the maximum rate of pressure rise during an explosion appears to be a function of the duration of the explosion, suggesting that the reaction rate plays a more pivotal role in determining the hazardous level. Meanwhile, the duration of fast combustion steadily occupies approximately 83 % of the explosion duration. Furthermore, the deflagration index is no more than 30 MPa*m/s, namely, ethanol/hydrogen mixture is a promising fuel with mild hazardous potential.