Experimental and mechanism research on the deflagration characteristics of H2/C2H5OH mixture under non-atmospheric conditions

Abstract

To ensure the safe production and utilization of hydrogen/ethanol fuel, the deflagration characteristics of hydrogen/ethanol mixture at elevated temperature and pressure (TAP) are investigated. The impacts of single factors, including temperature, pressure, fuel concentration, as well as the synergistic effect of TAP on explosion parameters are analyzed. Additionally, a comparative assessment is made based on the explosive pressure hazards posed by hydrogen, ethanol, and the hydrogen/ethanol mixture when subjected to high TAP. The results show that a linear relationship is observed between the initial pressure and the explosion pressure across varying concentrations of hydrogen/ethanol mixture. It is noted that the sum of the individual effects of initial TAP on the explosion pressure of the hydrogen/ethanol mixture is less than the effect of initial pressure alone, but greater than the combined effect of initial TAP. Moreover, the reliability of the NUI mechanism is verified by the laminar burning velocity obtained through the constant volume method. Sensitivity analyses are conducted to elucidate the key elementary reactions and clarify the reaction mechanisms of hydrogen/ethanol mixture. The increase in initial TAP only alters the temperature sensitivity coefficient, while the primary elementary reactions varies with increasing ethanol concentration. Finally, prediction models for predicting the explosion pressure of hydrogen/ethanol mixture at elevated TAP are established based on three algorithms, MLR, KNN and RF, respectively, in which the KNN model has higher predictive ability and better applicability.