Computer simulation of the operating pressure of tungsten halogen lamps

Abstract

The small bulb of the tungsten halogen lamp often operates at several hundred degrees Celsius and an internal pressure higher than atmospheric pressure. The cold lamp contains a gas filling at about 3 bar; the pressure during operation is much higher than that. The objective of our project is to analyse the internal operating conditions (such as the pressure and the thermal behaviour) of certain halogen lamps. The actual measurement of the operating conditions is far from easy. Rather, a computer model has been developed to evaluate the operating conditions in these lamps, based on the substantial partial differential equations of the free convection problem. This model can help determine the temperature distribution, the velocity field and the pressure in these lamps.The free convection has been simulated by the following two appropriate equations: the convection–conduction equation—it is the heat transfer equation for convecting materials—and the incompressible Navier–Stokes equation. We could get the temperature field from our results, which helped us to calculate the operating pressure of the lamps. The pressure dependence on dimensionless characteristic numbers was evaluated.