CFD simulations of heat transfer from a heated module in an air stream: Comparison with experiments and a parametric study

In the last decade or so, CFD simulations have become increasingly widely used in studies of electronic cooling. Validation of these simulations has been considered to be very important. Nakayama and Park (1994, 1996) have performed a series of experiments with the aim of measuring the heat transfer and flow field in the simple geometry of a heated chip in an air stream. They observed a number of complex features in both the flow field and heat transfer behaviour. In this study, their experimental geometry has been used to simulate the flow and temperature fields in a parallel-plate channel with a heated block mounted on the floor. The channel inlet flow velocity has been varied between 1 and 7 m/s. Various turbulence models have been tested, and the effect of the channel inlet flow on the heat transfer rate has been determined by considering both a uniform and fully-developed condition. The substrate adiabatic heat transfer coefficient is also numerically determined. The results indicate that the flow in the vicinity of the module is three-dimensional, and exhibits flow separation and vortex formation, hence leading to a complex distribution of the local heat transfer coefficient on the substrate. The air temperature next to the floor is strongly affected by the heat transfer from the block, which leads to the formation of a thermal wake downstream of the block. The experimental data is used to validate the CFD predictions and agreement for some parameters is shown to be favorable