Thermal spreading resistance of grooved vapor chamber heat spreader

•Thermal resistances of two grooved vapor chambers were experimentally studied.•Power input and charging ratio were two factors affecting its thermal performance.•Spreading resistance dominated in the total thermal resistance of vapor chamber.•Charging ratio affected effective thermal conductivity, hence spreading resistance. Thermal spreading resistance problem is encountered when the heat spreader is subjected to a concentrated heat source, which has attracted researchers’ attention for decades with the increasing heat flux of electronic packages or power electronic devices. Vapor chamber heat spreader has been regarded as one promising solution to this problem for its excellent thermal performance. In this work, two kinds of groove wick structure, i.e., radial groove and cross groove, copper-water vapor chamber heat spreader were fabricated and tested for their thermal performance. The dimension of the vapor chamber heat spreader was 120 mm × 120 mm × 7.5 mm. It was sandwiched between a heater copper block and an air-cooled aluminum heat sink. The effective heating area was 30 mm × 30 mm. The power input varied from 60 W to 350 W. Test results demonstrated that the thermal spreading resistance played an important role in the total thermal resistance of the vapor chamber heat spreader. In addition, the influence of charging ratio on the thermal spreading resistance of the vapor chamber was also numerically investigated.