Effect of rib diameter on flow boiling heat transfer with staggered rib arrays in a heat sink

With the integration development of electronic equipment, a more compact and higher efficiency heat dissipation system is required to meet its cooling demands. In this work, the design of ribbed channel heat sink in a limited volume to maximize its heat transfer capacity is analyzed. Two-phase flow boiling performance of rib diameters ranging from D = 1–10 mm is characterized using the Mixture multiphase model. The working fluid is coolant Novec649 and its mass flux is 1527 kg m⁻² s⁻¹. The heat fluxes imposed on the channel wall range from 50 to 300 kW m⁻². The results show that the average heat transfer coefficient increases and the wall temperature decreases with the increase of the rib diameter, respectively. The heat transfer performance factor increases with the decrease of heat fluxes, and first decreases with the increase of the rib diameters, then keeps constant. The comprehensive heat transfer performance factor is defined by temperature uniformity. It appears two maximum values which are located at D = 5 and 10 mm, one minimum value at D = 7.14 mm. The best comprehensive heat transfer performance of the heat sink is at D = 10 mm.