Experimental Investigation of a Flat-Plate Oscillating Heat Pipe With Groove-Enhanced Minichannels

Abstract

<jats:title>Abstract</jats:title> <jats:p>The thermal and capillary performance of a groove-enhanced, or ‘microchannel-embedded’, flat-plate oscillating heat pipe (MC FP-OHP) was experimentally investigated while varying heating width, orientation, working fluid and operating temperature. The copper MC FP-OHP possessed two layers of 1.02 × 1.02 mm2 square channels, with the center 14 channels possessing two embedded microchannels (0.25 × 0.13 mm2) aligned coaxially with the primary minichannels. A FP-OHP without embedded microchannels, but with deeper minichannels (DC FP-OHP), was also tested for comparison. The FP-OHPs were filled with Novec 7200 or water (both at 80% ± 2% by volume), and the heating widths were varied between full-width and localized configurations: 38.71 cm2 and 14.52 cm2, respectively. Experimental results demonstrate that the MC FP-OHP is significantly less sensitive to operating orientation and can perform with less detriment as heat flux increases. The MC FP-OHP has a lower startup heating requirement and provides more fluid wetting along the FP-OHP structure – which is advantageous for pumping liquid from the evaporator to condenser. The MC FP-OHP has enhanced convective heat transfer during operation, as it was observed to have similar or lower thermal resistances to that of the DC FP-OHP for a wide range of operating conditions. The groove-enhanced minichannel within the MC FP-OHP also provides for enhanced heat transfer due to there being more thin film evaporation sites and vapor-liquid mixing between the minichannel and microchannels</jats:p>

A Review of MHP Technology and Its Research Status in Cooling of Li-Ion Power Battery and PEMFC

“…Xu et al, 116 in order to improve the wettability of the wick and enhance the phase change heat transfer, added a superhydrophilic nano CuO coating to the surface of the MHP's inner channel, which improved the boiling heat transfer ability of heat pipes and reduced their thermal resistance. Rhodes et al 117 implanted microchannels into the MHP. The results show that the microchannels provide more surface wetting, film evaporation, two-phase mixing, and boundary layer disturbance than non-microchannels, which enhanced the heat transfer ability.…”