Experimental investigation on the effect of size modification of Alumina nano-additives on the performance and emission characteristics of a compression ignition engine

Particulate matter emissions from conventional automobiles are of great concern due to their significant health impacts. Upgradation of fuel has become essential for the reduction of these emissions. The study focuses on the effect of the size of aggregated Alumina (Al2O3) nanoparticles dispersed as nano-fuel on the emission and performance characteristics of a Compression Ignition engine. The size distribution of the dispersed nanoparticles significantly affects various physicochemical and transport properties of the nanofluids. In this work, effect of the size reduction of dispersed Alumina particles using mechanical methods like ball milling and ultra-sonication, on the emission and performance characteristics of a compression ignition engine, is studied in detail. The long-term dispersibility of the nano-fuel was studied using the Dynamic Light Scattering (DLS) technique. The particle stabilization through the inhibition of agglomerate formation was achieved with the surfactant Span80. The DLS analysis showed improvement in the long-term stability of dispersed particles when ball milling and bath sonication were combined with the surfactant. It was observed that the ball-milled Al2O3 particles remained dispersed even after 24 days of preparation. The nano-fuel sample with an Al2O3 concentration of 50 ppm and 100 ppm prepared using mechanical methods showed improved engine and emission characteristics. The results show a significant difference in the emission characteristics compared to neat diesel and nano-fuel prepared without ball milling. The maximum improvement in brake-specific fuel consumption, hydrocarbon emissions, nitrogen oxide emissions, and smoke opacity was found to be 16.8%, 27.4%, 25.1%, and 14.8%, respectively.