Air-methane mixture ignition with Multi-Walled Carbon NanoTubes (MWCNTs) and comparison with spark ignition

This paper presents the potentialities of a new ignition system based on exposition of multi-walled carbon nanotubes containing 75% in weight of ferrocene to a low-consumption flash camera. The experiments were performed in a constant-volume chamber equipped with an optical access, to allow the acquisition of high-speed camera images, and with a piezoresistive pressure sensor. The chamber was filled with an air-methane gaseous mixture and its combustion was triggered by flashing the nanotubes. The resulting combustion process was compared with the one obtained triggering the mixture ignition with a traditional spark plug. The combustion process was characterized for different air-methane ratios. The results show that the ignition with nanotubes determines a higher combustion pressure gradient and a higher peak pressure than spark ignition for all the tested air-methane ratios. Furthermore, high-speed camera images show that the ignition with nanotubes leads to a more distributed homogeneous-like combustion and then a faster consumption of the air-methane mixture without the formation of a discernible flame front.