Effect of thickness constraints on pool boiling morphology and heat transfer enhancement of different structural surfaces

With the rapid development of microelectronics technology, electronic devices are evolving toward higher performance and greater integration, posing serious thermal management challenges, as chip overheating may compromise their stable operation. Boiling phase-change heat transfer is a key approach for addressing thermal management in high-performance electronic devices. To further enhance its heat transfer performance, this study investigates the effects of four surface structures and thickness-constrained spacing on pool boiling heat transfer. A thickness-constraints boiling experimental platform was built, and four surfaces—copper plate, two layers #200 mesh (2*#200 mesh), spiral woven mesh composite flat mesh (SFCM), and spaced spiral woven mesh (SSWM)—were designed and fabricated. Boiling morphologies and heat transfer performances were examined at restricted spacings of 5.7, 0.7, and 0.4 mm. Experimental results indicate that spatial confinement shortens the bubble nucleation to escape cycle, thereby enhancing boiling heat transfer as spacing decreases. At 100 W heat load, the surface temperature (Tc) of the copper block at 0.1 mm confined spacing was about 5 °C (4.7%) lower than that at 5.7 mm. At 5.7 mm spacing and power above 25 W, the Tc order from low to high was SSWM, 2*#200 mesh, SFCM, and copper surface. When spacing was reduced to 0.4 mm, the order changed to SSWM, copper surface, 2*#200 mesh and SFCM. Among all configurations, the SSWM exhibited the best boiling heat transfer performance. Consequently, designing an ultra-thin confined structure above the heat source may help to improve heat transfer, and applying a SSWM-like structure is expected to further reduce the heat source temperature, offering guidance for optimizing design of phase-change dissipation devices.