Simulation of the Temperature Distribution in Automotive Head Lamps

Abstract

The design of head lamps plays an important part in the development process of modern cars as it contributes significantly to the first impression of a car. However, beyond the design aspect technical requirements have to be fulfilled. These are foremost the lighting properties, the quality of the product and its lifetime. In this respect, the knowledge of the maximum temperature of different components of the head lamp is of great importance during the development process, as the temperature limits of the various materials are not to be exceeded. Therefore, numerical simulation is an important tool for the prediction of temperature distributions in head lamps during the development process. The heat transfer in an automotive head lamp is a complicated process, as different mechanisms have to be taken into account. These are the conduction in the solid parts and the transport due to convection by the air, respectively. Furthermore, heat transport due to thermal radiation plays a dominant role. Together with Audi AG, Merkle & Partner has investigated a method to predict the temperature distribution in a head lamp by means of numerical simulation. Therefore we use Star-CD for the computation of the convective flow field and the software AURA for the calculation of the radiation heat transfer. Both codes are coupled by user-subroutines. Within this paper we want to briefly describe the methodology of the process. As an example a simplified model of an automotive head lamp is investigated. The influence of the different heat transfer mechanisms is described.