Study of cooling process of plasma jet flowing around a thin ablating graphite rod

Abstract

Abstract We present results of spectroscopic measurement of electron temperature in submerged nitrogen and argon mixture plasma jet for cases of free flow and introduction of thin graphite rod into the jet. The observed cooling of plasma caused by rod introduction agrees with the calculated enthalpy decrease from graphite rod heating and ablation. In this experiment, a marker was used to create artificial optical inhomogeneities in the flow, which allowed us to determine flow velocity from the analysis of their movement. In this case, we aim to determine the degree of influence of rod introduction into the plasma on its parameters. Upon introduction into the plasma, the rod was heated and partially destroyed by the plasma flow, reducing its temperature by 8-20% depending on the flow rate of the plasma-forming gas. The observed plasma cooling was compared with the calculated decrease in enthalpy caused by the cost of heating and ablation of the rod material.