Abstract: Grooved microchannels are used to enhance the capillary action in the transport line of two-phase heat dissipation devices, such as loop heat pipes, capillary pump loops, or spray cooling devices, or others. Efficient heat dissipations achieved by enhancing the capillary pumping force for the liquid flow without significantly increasing the friction force. The effective cross-sectional area of the liquid line is made smaller than that of the condensation section, either by inserting a plug or shrinking the liquid line, to provide additional pumping force for the coolant recycling.

Abstract: Heat from a heat generating device such as CPU is dissipated by a heat sink device containing a recycled two-phase vaporizable coolant. The coolant recycles inside a closed metal chamber, which has an upper section and a lower section connected by a conveying conduit, and a wick evaporator placed in connection with the lower section. The liquid coolant in the evaporator is vaporized by the heat from the heat generating device. The coolant vapor enters the upper section and condenses therein, with the liberated latent heat dissipated out through the inner top chamber wall. The condensed coolant is then collected and flows into the lower section, and further flows back to the wick evaporator by capillary action of the evaporator, thereby recycling the coolant. Space or a piece of element with parallel grooves is used to at least one of the sections to reduce friction in the liquid flow path.