Abstract
This paper discusses the thermal behavior of a high-pressure mercury lamp in a horizontal position compared to that of a vertical lamp when the supply current varies. The model adopted is 3-D, steady, and dc powered. After the validation of the model, pressure of the lamp is kept at 6 × 10 5 Pa and the supply current varied from 1 to 10 A. Then, by comparing the case of the lamp in a horizontal position with that in a vertical one, the temperature fields, the flow of heat conduction, the flow of convective heat, and the accumulation of mercury behind the electrodes are analyzed.