Passive two-phase cooling solution with a novel heat transfer enhancement technique for electronic packages

A passive two-phase cooling solution for electronics package is presented in this paper. The heat from the electronics is removed by nucleate boiling. A novel pool boiling enhancement technique is developed and characterized as part of this work. The boiling heat transfer enhancement is obtained using surface modification and micro-machined porous channels (MMPC). An experimental rig is developed to investigate the heat transfer enhancement by the technique and compared with heat transfer from a plain silicon surface. Critical heat flux from a horizontally oriented silicon chip using fluorocarbon liquid FC-72 is found to be 14.8 W/cm². Boiling heat transfer limits of the designed enhancement technique is investigated. The pore size in the MMPC structure is found to influence the heat removal capabilities. Maximum heat flux of 45.6 W/cm² is handled with a MMPC structure having 0.5 mm pore size in 0.5 mm width channels. One MMPC structure is integrated with a 40 mm BGA and gravity driven two-phase cooling solution is developed. The cooling limit of the cooling solution is tested and reported