Effect of swirl flow on an atmospheric inductively coupled plasma supersonic jet

Recently supersonic jets extracted from atmospheric inductively coupled plasmas (ICP) have attracted a lot of attention. Usually atmospheric ICP generators have employed swirl flow injection in order to stabilize the plasma. However the effect of the swirl flow injection on the performance of atmospheric ICP generators has not been understood enough. This work found that the injection of the swirl flow deteriorates the performance. First we conducted the total enthalpy measurement based on the sonic flow method and evaluated the averaged specific enthalpy. Then laser absorption spectroscopy was employed in order to measure the temperature and the velocity of the extracted supersonic jet. The both measurements observed that the specific enthalpy of the jets decreased with the increase in the swirl flow fraction. This would be because the swirl flow affected the shape and the position of the plasma significantly.