Air cooling augmentation in an array of heated modules by horizontal semicircular cylindrical shells as cross flow barriers

Abstract

A three dimensional study of air cooling from an array of heated blocks in a rectangular channel for a range of Reynolds number is presented. Heated blocks represent electronic modules mounted on horizontal circuit boards. Numerically obtained average heat transfer coefficients for the top surface of the heated modules are compared with experimentally obtained values, and it is found that there is a good agreement between the two at low Reynolds numbers. Further, circular cylinders, semi-circular cylinders, and semicircular cylindrical shells with length equal to the width of the channel are introduced as flow barriers in the domain separately to study the influence on heat transfer and pressure drop. These horizontal cylinders over each row of modules in cross flow augment heat transfer from the heated modules considerably. The heat transfer enhancement is found to be more dependent on the vertical position of the cylinders with respect to the modules than on the horizontal position. Air cooling is predicted to be augmented from the modules by shifting the cylinders closer to the heated modules up to a certain limiting distance, and beyond which the heat transfer decreases. Semicircular cylindrical shells prove more beneficial than any of the other two barriers for heat transfer enhancement from the modules. It is observed that the semicircular shells in cross flow result in lesser pressure drop when compared to semicircular cylinders, though the former produces maximum heat transfer from the modules.