Two-phase Closed Thermosyphon with Nanofluids

Nanofluids, stabilized suspensions of nanoparticles typically < 100 nm in conventional fluids, are evolving as potential enhanced heat transfer fluids due to their better thermal conductivity, increase in single phase heat transfer coefficient and significant increase in critical boiling heat flux. In the present paper, we investigate the overall thermal resistance of a closed two-phase thermosyphon using pure water and various water based nanofluids (of Al2O3, CuO and Laponite clay) as working fluids. We observed that all these nanofluids show inferior thermal performance than pure water. Furthermore, it is observed that the wettability of all nanofluids on copper substrate, having the same average roughness as that of the thermosyphon container pipe, is better than that of pure water. The behavior of nanofluids is explained in the light of pool boiling dynamics and the interplay of nucleating cavities with wettability of the nanofluids.