Evaluation of the Effects of Roll Angle on the Natural Convection Heat Transfer from an Array of Cylindrical Spines

摘要

Electronically steered phased array antennae frequently exhibit degraded performance due to the lack of proper heat transfer between the interior crystalline materials and the environment. This causes higher than optimum temperature environments for the crystalline materials and a subsequent loss of reliability. One possible solution to such a problem considers a surface augmentation through the use of pin fins (or spines) to assist in the dissipation of the heat. Experimental data has been obtained that predicts the effect of roll angle upon the natural convection heat transfer from an array of cylindrical spines or pin fins. A correlation is presented that permits evaluation of the Nusselt Modulus as a function of the Rayleigh Modulus and the roll angle and it shows that maximum heat transfer is obtained at roll angles between 20 and 30 degrees.