Effects of solids' concentration and oleic acid dispersant on the stability and combustion characteristics of aluminum/bioethanol nanofluid fuel

In this work, four samples of nanofluid fuel were prepared by sequentially blending bioethanol with 1 wt% aluminum (Al), 5 wt% Al, 10 wt% Al, and 5 wt% Al + 1 wt% oleic acid (OA). The stability and combustion characteristics of the samples were investigated. The experimental results show that the addition of OA had a beneficial effect on the stability of samples by preventing the formation and growth of Al agglomerates. Moreover, the sample containing OA showed the shortest normalized ignition delay time (0.015 s/mm2), the largest combustion rate constant (28.79 mm2/s), and the highest maximum surface temperature (932.60 °C) during combustion. The increase in solids' concentration is also helpful in improving the stability, ignition, and energy release of the samples within the studied ranges of the parameters. However, excessive solids' concentration enlarges the size of Al core during combustion and will further decrease the overall combustion efficiency. The present work provided a comprehensive experimental investigation towards the effects of solids' concentration and OA dispersant on the stability and combustion characteristics of Al/bioethanol nanofluid fuels. [Display omitted] •Stability and combustion characteristics of Al/bioethanol nanofluid fuel are studied.•Effects of solids' concentration and oleic acid are compared experimentally.•Stability was analyzed by comparing settling time and microstructure of sediments.•A laser ignition testing system was designed for the combustion experiments.•Oleic acid turns out to be a superior additive for Al/bioethanol nanofluid fuels.