Numerical analysis of heat transfer in a compact plastic ball grid array package air cooling model

The thermal performance of a temple package air cooling model composed of a 672-pin plastic ball grid array (PBGA) package mounted on a printed circuit board (PCB) and a compact system box has been investigated by numerical simulations of heat transfer. A geometry model resembling the PBGA/PCB package with directional homogeneous solid blocks was constructed, and a three-dimensional computational approach of thermal flow simulation was developed considering conduction and convection modes of heat transfer. Having been verified by experimental results, the approach was applied to the analysis of heat transfer in the package air cooling system. Computational results show that the thermal resistance of PGBA/PCB package model under the condition of natural air cooling is about 27.0 K/W and closes to 25.0 K/W gradually with the increase of heat spreading. Under the condition of forced air cooling, its thermal resistance decreases with the increase of airflow velocity, and the reasonable velocity of air cooling is revealed to be about 0.8 m/s.