Spectroscopic detection of carbon particulates from a high speed jet stream with extended plasma visualization

The detection of carbon is conducted by the Laser Induced Breakdown Spectroscopy (LIBS) in the flow system for replication of aircraft exhaust flow conditions. The flow visualization is conducted in addition to the spectroscopic analysis to validate the LIBS results. In the elemental analysis, both C (247.86 nm) and CN band (388.3 nm) peaks are selected for detecting carbon. The detected signals from the emissions stream of velocity up to 70 m/s showed that in-situ characterization of carbon particulates in the high speed exhaust are proven feasible.