HEAT-TRANSFER AND COLD-CATHODE EROSION IN ELECTRIC-ARC HEATERS

A simple thermophysical model is proposed for cold electrode erosion i n electric are heaters. The model regards erosion as characterized by an effective enthalpy of electrode material ablation, resulting in hea t unbalance between heat supply and heat removal by conduction, Replac ing the are spot by a moving surface heat source, the space-time evolu tion of the electrode surface temperature is studied in coordinates co upled to the source. Applying heat diffusion equations, we show that t he erosion problem can be represented by a system of three simple equa tions, An experimental coaxial setup, with a magnetically driven are, has been used for the erosion measurements in copper electrodes. Speci al thermal experiments were carried out for measuring needed are spot parameters, A comparison of the model with our own and other experimen tal data demonstrates a reasonable agreement. The present model reveal s the relative significance of the different parameters in the erosion process, and permits us to predict the erosion behavior in cold elect rode electric are heaters in a wide range of parameters.