Application of CCD Cameras to Investigations of Mixing on Boundaries of a Thermal Plasma Jet

摘要

Mixing of a thermal plasma jet with the surrounding atmosphere was studied using two CCD cameras (PCO SensiCam) situated detecting simultaneously the radiation of argon and nitrogen.The evaluation of image differences between two records showed that the location of regions on plasma jet boundaries characterised by stronger nitrogen radiation changes with the plasma flow rate.Close-to-laminar flow results in a small mixing rate and consequently low nitrogen optical emission on plasma jet boundaries.The increase of the flow rate leads to the formation of a relatively thick and stable layer on the boundaries characterised by strong nitrogen radiation.Further enhancement of the flow rate results in the formation of unstable regions of excited nitrogen molecules moving along the jet.