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).

摘要

在层流强制对流传热模式下进行稳态实验，用于冷却安装在基板不同位置的七个非对称IC芯片（热源）。板子以不同的角度定向，即0 ^°（水平）、30 ^°、60 ^°和90 ^°（垂直）研究其对 IC 芯片冷却的影响。目标是确定最佳配置（这七个 IC 芯片在板上的排列），从而最大限度地降低它们的最高温度。最佳配置是通过采用混合优化策略来确定的，该策略将人工神经网络 (ANN) 与遗传算法 (GA) 相结合，并通过合适的实验进一步验证。提出了不同的相关性来研究基板方向对 IC 芯片的 Nusselt 数（冷却速率）和温度的影响。结果表明，IC 芯片的温度是其尺寸、基板上的位置、输入热通量和基板方向的强函数。IC芯片的温度最低为30 ^°定向板，对于这种情况，板的最大表面积与流动的空气接触。这有助于有效冷却芯片以降低其温度。可用于散发 IC 芯片热量的表面积在 30 ^°后继续减少。对于垂直方向，进入基板入口部分的空气与其垂直。因此，IC芯片的温度对于垂直基板是最高的。空气速度对于 IC 芯片的冷却也很重要。与较低的速度 (4.5 m/s) 相比，较高速度 (8 m/s) 的温度下降了 1.42-17.33%。