No abstract

Torch plasma arcs have useful high-energy and high-current characteristics. Torch plasma arcs can be flexible even if exposed to high-speed laterally flowing gases. This study measured the length, voltage, input power, heat power and heat efficiency of a torch plasma arc to the anode to elucidate their influence upon the plasma torch arc anode attachment with a high-velocity laterally flowing gas. That velocity was varied from 0 to 60 m s −1 . The axial plasma gas argon flow rates used were 4, 8 and 12 slpm. Consequently, the input power increased about 8000-16 000 W with these lateral gas air velocities. The heat efficiency decreased with lateral gas air velocity from about 50% to 25% at a current of I = 150 A. The torch plasma arc length, L a , was ca 1 cm. The results of this study are applicable for providing electrical power from the ground to high-speed vehicles or vice versa and for reducing anode erosion by anode spot movement.

Thermodynamicproperties such as enthalpy and specific heat, and viscosity of different compositions of argon-iron mixture gases are calculated under the assumption of local thermal equilibrium for a temperature range of 2,500K to 30,000K.The enthalpy decreases basically with increasing iron vapor content, however increases in the temperature range between 5,000 and 14,000K due to the ionization of iron atoms around 7,000K. The specific heat changes complexly with temperature having several peaks corresponding to the ionization of iron and argon atoms and their ions. The viscosity decreases with increasing iron vapor content above the temperature range of 6,000K due to the iron ions, which have a relatively large coulombic cross section. Increasing pressure causes the enthalpy to be decreased, however the viscosity to be increased. This result comes from the upward shift of temperature region in which the ionization reactions proceed efficiently.

No abstract

No abstract