CONSIDERATIONS ON THE IMPORTANCE OF PROPER HEAT TRANSFER COEFFICIENT MODELING IN AIR COOLED ELECTRONIC SYSTEMS

This paper illustrates, based on a practical example of a hybrid circuit, the influence of proper heat transfer coefficient modelling in air cooled electronic systems on the accuracy of thermal simulations. This circuit contains a transistor heat source and a set of temperature sensors. The measurements of their temperature responses are taken in natural convection and forced air cooling conditions. The experimental data provide the information necessary to estimate the local heat transfer coefficient values in heat source and temperature sensor locations. Moreover, the experiments rendered possible the fitting of parameters of an empirical heat transfer coefficient model for different surface temperature rise values and cooling air velocities, and hence allowed significant improvement of thermal simulation accuracy.