Enhancement of Saturation Boiling of PF-5060 on Microporous Copper Dendrite Surfaces

Experiments are performed to investigate saturation boiling of degassed PF-5060 dielectric liquid on microporous copper dendrite surface layers deposited on $10×10mm2$ Cu substrates. The electrochemically deposited surface layers are of different thicknesses (⁠$145.6μm$⁠, $46.3μm$⁠, and $33.1μm$⁠). The thickest layer gives the best results: the saturation CHF of $25.27W/cm2$ occurs at a surface superheat of only 2.9 K and the maximum nucleate boiling heat transfer coefficient, $hMNB$⁠, near the end of the fully developed nucleate boiling region, is $8.76W/cm2K$⁠. In addition, nucleate boiling ensues at a surface temperature slightly above saturation $(<0.5K)$⁠, with no temperature excursion. The temperature excursions before initiating boiling on the $46.3μm$ and $33.1μm$ thick Cu nanodendrite surface layers are small (3.7 K and 6 K), corresponding to surface temperatures of $∼55.1°C$ and $57.4°C$⁠, respectively. These temperatures are much lower than recommended $(85°C)$ for reliable operation of most silicon electronics and central processor units.