CALCULATION OF TEMPERATURE PROFILES OF HIGH PRESSURE ELECTRIC ARCS USING DIFFUSION APPROXIMATION FOR RADIATION TRANSFER

A method is described for calculating the temperature profiles of high pressure electric arcs using the diffusion approximation for radiation flux density. Account is taken of energy transfer due to thermal conduction, emission and absorption of radiation. The input material functions that are required are the thermal and electrical conductivity and the spectral absorptivity as a function of temperature. By representing the radiation as fourteen continuum bands of equal width, extending to 7×1015Hz (400 Å), numerical results have been obtained for arcs in air at 30 atm and 100 atm gas pressure. It is shown that for high input power densities and for high gas pressures, self-absorption of radiation in the ultraviolet has a considerable effect on the temperature profile. Calculations using the diffusion approximation with different boundary conditions are compared with exact calculations. © 1969.