Ignition and combustion characteristics of magnesium-based nanofluid fuel.

Mg-based nanofluid fuel is a promising fuel for propulsion system in Mars exploration. In this study, Mg-based nanofluid fuel were prepared by one-step method, and the effect of Mg(magnesium) content, Mg size(68 μm,110 μm,175 μm), and oleic acid (OA) on droplet ignition and combustion under the atmosphere of 90 % CO 2 and 10 % O 2 were investigated. According to the TG-DSC results, 68 m Mg particles under CO 2 had the highest exothermic efficiency of 4472 J/g. The combustion of Mg/OA/kerosene droplets consists of five stages: ignition, d2-law combustion, micro-explosion, vapor flame extinguishment, and agglomerate explosion. The ignition delay time of Mg (68 μm, 5 %)/kerosene is 0.045s, which is half that of kerosene (0.0890s). The agglomerates explode violently and emit a brilliant white light at the end of the Mg-based nanofluid fuel combustion. The explosive effect of Mg agglomerates diminishes as the Mg content increases. The rate of combustion decreases with increasing particle size. In the sample with added oleic acid, Mg (68 μm, 5 %)/OA/kerosene shows the best combustion rate of 0.6320 mm2/s. Finally, a numerical model for the combustion of Mg-based nanofluid fuel droplets is proposed. The predictions are within 2 % of the experimental results. The findings are expected to explore future in-situ utilization of CO 2 on the Mars surface. • Combustion characteristics of a novel Mg-based nanofluid fuel for Mars are studied. • Effects of Mg particle size and content on the combustion properties are analyzed. • The optimal Mg-based nanofluid fuel formulation is Mg (5 wt%, 68um)/OA/kerosene. • A numerical model for the combustion of Mg-based nanofluid fuel droplet is proposed. [ABSTRACT FROM AUTHOR]