Enhanced nucleate pool boiling on copper-diamond textured surfaces

• Published in: Applied thermal engineering 2019-11, Vol.162, p.114145, Article 114145
• Main Authors: MacNamara, R.J., Lupton, T.L., Lupoi, R., Robinson, A.J.
• Format: Article
• Language: English
• Subjects: Copper; Diamonds; Experiments; Heat flux; Heat transfer; Heat transfer coefficients; Hydrophobic surfaces; Multiscale analysis; Thin films
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2019.114145

•A solid state additive manufacturing technology is used for coating boiling surfaces.•Cu-Diamond composite surfaces are fabricated using Cold Spray manufacturing technology.•Heat transfer enhancement of up to 300% is achieved with a 35% increase in CHF.•Capillary wicking is proposed as an important mechanism of enhanced boiling. This work describes an experimental investigation of enhanced nucleate pool boiling of water on textured surfaces. The textured surfaces are formed atop thin Copper-Diamond composite layers deposited by the Cold Spray manufacturing technique. The resulting surface is multi-scale, mildly hydrophobic and supports liquid wicking. Pool boiling experiments are performed on coated and non-coated surfaces and performance improvements are quantified in terms of enhanced boiling heat transfer coefficients and CHF. Heat transfer coefficient enhancement levels increased with applied heat flux up to 300%, achieving 200 kW/m2 K on the textured surfaces. CHF was enhanced with the textured surface up to ∼35%, achieving over 1500 kW/m2. Some qualitative descriptions of the boiling process on both the plain and textured surfaces are provided by evaluating high speed video footage. It is hypothesized here that at high heat fluxes (>1000 kW/m2), capillary wicking in the textured surfaces plays a key role in both the very high heat transfer coefficients and improved CHF.