Experimental and kinetic study on the laminar burning velocities of NH3 mixing with hydrous C2H5OH in premixed flames

Abstract

In the present work, the laminar burning velocities of NH₃ + hydrous C₂H₅OH + air flames were measured using the heat flux method at 1 atm with varied equivalence ratios and mixing ratios (with hydrous ethanol molar fractions of 45%–75%). The measurements were carried out at unburned temperatures of 358 and 378 K. The results show that the laminar burning velocities increase with the increase of hydrous ethanol mixing ratio and temperature, indicating that hydrous ethanol contributes to the combustion of NH₃ flames. Based on Wang et al.'s CEU-NH3 mechanism, sensitivity, reaction pathways, and product formation rate analyses were conducted. The results show that the addition of water reduces the laminar burning velocities of mixed fuel. Intermediate radicals such as NH and HNO are crucial for the formation of NO. After adding water, in the preheating zone, the total production rates of key species such as NH₃, H, O, and OH radicals and intermediate species like NH₂, NH, HNO, and N decrease, leading to a reduction in the total NO generation rate and the peak mole fraction of NO in the reaction zone.