'Middle East Technical University, Faculty of Architecture'
Abstract
An electronics package on a rotary platform including two components with 600 W, one component with 350 W and one small component with 70 W heat dissipation rates (1620 W total heat load) is numerically and experimentally investigated under steady state conditions. In order to avoid rotary joints and to reduce the costs of design, maintenance and production, the thermal management solution for the heat dissipation is entirely placed on the rotary platform. The thermal management solution includes heat sinks attached to the vertical side surfaces of the platform and heat pipes connected to heat sinks. The heat dissipating components are connected to the heat sinks with heat pipes. The heat sinks are cooled by forced convection with high power fan assemblies. Two different fin configurations are considered. One of them is a pin fin design and the other one is a plate fin covered with duct design. The thermal management systems are numerically modeled and then one of the numerical models is validated with a set of experiments. The validated model is used for the optimization of the system and as a demonstration of feasibility of the heat pipes. The optimization parameters are the heat pipe locations, their connections to the heat sinks and geometrical properties of the heat sinks. The optimization criteria are to maintain nearly uniform temperature distributions on the heat sinks and to keep critical components below their thermal shut-down points. The constraints are the lengths of the standard heat pipes and the limited options to bend the heat pipes due to their fragile structures. The success of the system is that it can keep the hot spot temperatures below the allowed maximum temperature of 120 oC even for the case of 50 °C ambient air temperature. The limitation of 120 oC working temperature comes from the thermal shut-down limits of the components in the electronics package.M.S. - Master of Scienc