Revealing the effect of Ni NPs on the ignition characteristics of Al/ethanol nanofluid fuel: Experimental and DFT insights

Abstract

Aluminum (Al)/ethanol (EtOH) nanofluid fuel with high energy can be used in aerospace engine. However, the propellant performance will be limited by the easy oxidation of aluminum nanoparticles (Al NPs). The use of Ni nanoparticles (Ni NPs) to improve the ignition characteristics of Al-based nanofluid fuels is a feasible approach. In this work, the ignition delay of the Al-Ni/EtOH nanofluid fuel was investigated and the catalytic mechanism of Ni NPs on the decomposition of EtOH droplet was analyzed by a density functional theory (DFT). As the concentration of Ni NPs increases, the ignition delay of the Al/EtOH droplet decreases. In addition, the “CH3CH2OH → CH3CH2O → CH3CHO → CH3CO → CH3C → CH2C → CHC → CC” is the most preferred route for the breakdown of EtOH on the Ni (111) surface, in which the process of CH3C to yield CH2C is the rate-limiting step. The results of the adsorption properties of the relevant intermediate species indicate the existence of the chemical interactions between them and the Ni (111) surface. These results are expected to provide some information and theoretical ideas for the future modification of metal particles in nanofluid fuels.