Three-Dimensional Multiphysics Analyses of a CPU Integrated Thermal Heat Sink
Recent advances in electronic packaging have led to small, lightweight and highly efficient heat sink designs. Some of these attempts are aiming to integrate the heat sink with the packaging wall structure. In this paper, a three-dimensional multiphysics numerical model is developed for the integrated heat sink to carry out CFD and thermal analyses, stress analyses due to thermal expansion and modal analyses. Finite volumes were used to model the conjugate heat transfer (CHT) for the coupled fluid-structure fields representing the air and heat sink fin walls and base, respectively. In this analysis, both natural and forced convection analyses were considered. The predicted temperature distribution was then used to calculate the mechanical stresses due to thermal expansion, using finite elements. Lastly, modal analyses were conducted to calculate the natural frequencies of the model. The effect of varying the source heat generation rate, air flow speed, and some geometry features such as number of fins and fin’s height on the performance and structural integrity of the assembly have been studied.