3-D thermo-fluid computer simulations of high intensity discharge lamps

Summary form only given, as follows. A 3-dimensional thermo-fluid finite-element simulation of horizontal and vertical high intensity discharge (hid) lamps was performed. The governing equations are the Navier-Stokes equations and Poisson´s equation; the latter allows for volumetric Joule heating that is included in the energy balance equation. The simulations show that there is a single convection cell when the hid lamp is operated in vertical orientation. When the lamp is rotated 90 degrees (horizontal orientation) the results show the effects of gravity by bowing upwards the arc core of the gas discharge and the development of two disconnected convection cells. An animation of a particle tracer will be exhibited.