An improved vapor chamber with enhanced two-phase transport by using structured surfaces

The novel type of vapor chamber (VC) with combined superhydrophilic/superhydrophobic surface holds great potential in hot spot cooling. In this study, an improved VC was developed by implementing structured surfaces on both condenser and evaporator. The thermal resistance, condenser temperature uniformity, and gravity independence were discussed. It was found that sintering an appropriate copper mesh on condenser could reduce the thermal resistance but would cause a slight deterioration in the temperature uniformity of the condenser. On the evaporator, the thermal performance of VC was further improved by introducing micro grooves on the wick in order to enhance bubble discharge of the boiling working fluid. Moreover, to strengthen the liquid recirculation on the evaporator, pore size gradient was adopted in the evaporator wick. Compared to the axial gradient of pore size, the radial gradient of pore size was more efficient in accelerating the working fluid recirculation. Among all the results reported in this study, the combination of sintering copper mesh on the condenser and implementing micro-grooves and pore size gradient on the evaporator wick yields optimal results, with the minimum thermal resistance of the VC reaching 0.041 K/W and the critical heat flux exceeding 213.3 W/cm2, which shows excellent thermal performance.