Ignition and combustion mechanism of alcohol/aluminum suspension nano-fluid droplets

Abstract

The ignition and combustion of nano-fluid fuels composed of alcohol and nano-aluminum (ANP) lack atomic insights. A nanodroplet with methanol as shell and ANP as core was constructed for reactive molecular dynamic simulation. Combustion of nano-droplets can be divided into four stages: I: methanol volatilization accompanied by reaction with ANP; II: methanol fragment reacts with O2 and ANP accompanied by chain expansion; III: micro-explosion of composite aluminized phase; IV: gas phase combustion. ANP accelerates the CH3OH decomposition, reduces the ignition delay and activation energy. ANP extract hydrogen and oxygen accelerates the decomposition of CH3OH and forms H-Al and O-Al. H-Al releases H and H2, which leads to rapid generation of active fragments such as O, H, HO2, OH and CHx. It is the fundamental for reducing ignition delay. High temperature accelerates hydrogen extraction of ANP and make micro-explosion more intense. ANP increases the yield of H2O and CO2. This work explains the ignition and combustion mechanism of ANP/CH3OH, hoping to provide insights into alcohol-nanofluid fuel application in engine.