Experimental study of pool boiling heat transfer on an annealed TiO2 nanofilm heating surface
The hydrothermal stability of titanium oxide (TiO 2 ) made it a potential candidate in nanofilm (NF) coating on heating substrate for pool boiling enhancement ramified under passive technique. The objective is to conduct an experimental study on pool boiling of saturated water by the implementation...
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Veröffentlicht in: | Journal of thermal analysis and calorimetry 2021, Vol.144 (3), p.1073-1082 |
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Hauptverfasser: | , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | The hydrothermal stability of titanium oxide (TiO
2
) made it a potential candidate in nanofilm (NF) coating on heating substrate for pool boiling enhancement ramified under passive technique. The objective is to conduct an experimental study on pool boiling of saturated water by the implementation of an annealed TiO
2
micro-/nanostructured heating surface for the enhancement of heat transfer between the liquid and the heating surface envisioned as the corollary of annealing. Electron beam physical vapour deposition is employed to synthesize four TiO
2
nanofilm-coated substrates of two different thicknesses (500 and 100 nm); among them, one from each thickness is annealed at an inert atmosphere. The test samples are characterized by transmission electron microscopy, scanning electron microscopy, and atomic force microscopy and contact angle metre (dynamic) to understand the morphology, topology and crystallinity and hydrophilicity of the surface. Experimental analysis of heating surfaces revealed that the annealed TiO
2
1000 nm micro-/nanostructure-recorded maximum reduction in wall super heat (Δ
T
) of 52% and enhancement in heat transfer coefficient (
h
) of 74% than untreated copper substrate also exhibit superior structural stability after several runs rendering annealing a potential method for the amelioration of nucleation and structural stability of heating substrates. As hypothesized, annealing of nanofilm coating improved the structural stability of the NF rendering unwavering boiling performance evident from the results. |
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ISSN: | 1388-6150 1588-2926 |
DOI: | 10.1007/s10973-020-09503-3 |