Numerical simulation of combined natural convection-conduction cooling of multiple protruding chips on a series of parallel substrates

The advantages of natural convection cooling have prompted many experimental and numerical investigations to determine the heat transfer performance of microelectronic components. In this study, we have performed two-dimensional numerical simulations for prediction of the natural convection flow and heat transfer behaviour of a vertical board of finite thermal conductivity with a number of protruding chips mounted on it. A series of parallel substrates open at the top and bottom are considered which allows the use of repeated boundary conditions. In order to validate the CFD code, the experimental results of Fujii et al (1996) are used, and their geometry of a realistically sized board with 18 protruded chips is adopted. Simulations have been performed with various substrate thermal conductivities and channel widths. The chip power level has been varied over the range of a realistic chip temperature. The relationship between the induced flow rate and natural convection parameters is examined. The results indicate that conduction in the solid has an important effect on the flow and temperature fields in the fluid and strongly affects heat transfer behaviour.