Effect of current connection to the anode nozzle on plasma torch efficiency

Experiments have been performed to demonstrate the influence of the location of the electric power connection to the anode nozzle on the efficiency of de plasma torches, The de plasma torch used in these experiments offers the flexibility to work with different anode geometries and the possibility of connecting the electrical power to the anode at two different locations, For each set of experiments, the controllable parameters such as total gas how rate, gas composition, and electric current were kept constant, changing only the location of the electrical connection to the anode nozzle, The efficiency of the torch, derived from a conventional energy balance, shows a significant change as the location of the electrical connection to the anode nozzle is changed, The measured mean voltage as well as the amplitude of the voltage fluctuations were also affected by the location of the electrical connection to the anode nozzle, An explanation for the are behavior is given, based on an analysis of the forces acting on the anode are column and their influence on the variation of the are column length, Experimental data are in good agreement with analytical predictions.