Experimental investigation of substrate board orientation effect on the optimal distribution of IC chips under forced convection

Abstract

ABSTRACT Steady-state experiments are conducted under the laminar forced convection heat transfer mode for the cooling of seven asymmetric IC chips (heat sources) mounted at different positions on the substrate board. The board is oriented at different angles, i.e., at 0° (horizontal), 30°, 60°, and 90° (vertical) to study its effect on the cooling of the IC chips. The goal is to determine the optimum configuration (arrangement of these seven IC chips on the board) leading to minimize their maximum temperature. The optimal configuration is determined by employing a hybrid optimization strategy that combines the Artificial neural network (ANN) with Genetic algorithm (GA) which is further validated with suitable experiments. Different correlations are proposed to study the effect of the substrate board orientation on the Nusselt number (cooling rate) and temperature of the IC chips. The results suggest that the temperature of the IC chips is a strong function of their size, positioning on the substrate board, input heat flux, and the substrate board orientation. The temperature of the IC chips is least for the 30° oriented board, as for this case, the maximum surface area of the board is in contact with the flowing air. This helps in cooling the chips effectively in lowering their temperature. The surface area available to dissipate the heat from the IC chips keeps on decreasing after the 30°. For the vertical orientation, the air entering the inlet section of the substrate board hits perpendicular to it. Hence, the temperature of the IC chips is maximum for the vertical substrate board. Air velocity is also crucial for the cooling of the IC chips. There is a temperature drop of 1.42–17.33% for the higher velocity (8 m/s) as compared to the lower one (4.5 m/s).