The combustion of metallic nanoparticles : iron and aluminum as possible candidates for metallic fuel in an internal combustion engine

This work is focused on the combustion of metallic nano-particles under an air flow, with the aim of using them as potential fuels for Internal Combustion Engines (ICEs). This thesis is part of an European Project, called COMETNANO: it is an EU-funded, 3-years project, focusing on the evaluation of metallic nano-particles as fuel. It is an integrated approach studying the synthesis of metallic nano-particles, their controlled combustion under realistic conditions and the recycling of such spent fuels by renewable means. In particular, this work is focused on the investigation of different kinds of nano-particles in a cylinder chamber, in order to test their behavior during combustion under engine conditions: the approach is both quantitative (measurements of pressure and luminous intensity) and qualitative and supported by a video-optical system. Following this, data resulting from tests are post-processed to obtain important information on the way in which these particles burn. The nano-particles investigated are different in type and dimension: • Iron: 25 – 50 – 70 - 85 nm • Aluminum: 18 – 85 nm The tests show that iron gives better opportunities to reach the aim of this project. Moreover, in accordance with project aim, a study on NOx emissions was carried out: a set of tests on iron and aluminum under different operating conditions was performed and the exhausted gas analyzed. The results clearly show that NO’s concentration is the only one detected, although its value is very small. Finally, it has been presented an investigation on regenerated nano-particles; in fact, one of COMETNANO main goal was the possibility to re-use burnt nano-powders after a regeneration process. Consequently, after the realization of a suitable method for their production, their combustion behavior was tested and compared with the original particles.