Numerical optimization and experimental validation of vapor chambers having an outwardly protruding boss

Abstract

The purpose of vapor chamber (VC) is to spread heat from small concentrated heat sources. In practice, a protruding boss surface on the VC is used to meet the layout of printed circuit board assembly. This study numerically examines the effect of outwardly protruding boss on the performance of the VC subject to various geometrical design parameters under varying heat load conditions. The overall thermal resistance, spreading resistance, and temperature distribution are monitored to characterize the thermal performance. The experimentally validated numerical model is used to undertake parametric studies of the VC. It is found that the compound pillars and the area ratio in the boss region have significant effect on the thermal performance of the VC. The shape of compound pillars in the peripheral region, and the impact of the height of the vapor region are also studied. Pillar diameter and the number of pillars in the boss region impose the maximum effect on the performance of the VC as they directly influence the evaporative heat transfer and the surface temperature. The optimal design based on the compound pillar structures and area ratio in the boss region reduces overall thermal and spreading resistances by 18.2% and 18.9%, respectively.