数値計算シミュレータを用いたプラズマ噴流挙動支配要因の検討

プラズマアーク切断機構に関する研究(第2報)

抄録

The authors had investigated the kerf formation phenomena in an argon plasma cutting and in a nitrogen one in the previous report. Then, it was clarified that the optimal value of cutting speed for minimum bevel angle condition is different from that for minimum dross adhesion one. This fact suggests that the plasma arc behavior generated within the copper nozzle due to constricting the arc remarkably influences the kerf formation phenomena in the plasma arc cutting.
However, it is not easy to examine the plasma arc behavior by experimental methods. Especially, the behavior within nozzle cannot be observed by the experimental method.
So, the authors tried to make a numerical simulator to estimate the flow behavior of plasma arc within and out of nozzle. Then, governing factors of the plasma behavior were examined with the new simulator.
Consequently, it was concluded that the dissociation phenomena of working gases influence on the radial temperature and velocity distribution of plasma arc. Then, the mixing phenomena of surrounding gas into plasma arc flow govern the spreading phenomena of arc diameter out of the nozzle.
Moreover, the influences of arc current and working gas flow rate on the radial temperature and velocity distributions are clarified in the present study.