Abstract
Vertically standing mercury-arc discharge was investigated with a fluid model which treated radiation power due to optically thick lines precisely. Transport coefficients were determined using on electron-mercury atom collision cross section which was recently measured by England and Elford. The radiation power which was expressed as a function of temperature agreed with experiment for a 400-W operation. Variations of temperature and axial velocity were studied as a function of tube radius. At the central region, it was found that the input power almost transferred to radiation power for large tube radii and that it was mainly consumed as heat conduction loss for small tube radii. Normalized axial velocity profile along the radial direction was almost independent of the tube radius, although its maximum value increased with increase in the tube radius.