Nanoparticle deposition on roughened copper surfaces via nanofluid pool boiling

Nanofluid pool boiling is assessed as a technique for controlled nanoparticle deposition, which can produce surfaces with enhanced nucleate boiling performance. This paper presents nanoparticulate deposits obtained during Cu-water (1.6 wt%) nanofluid pool boiling on a roughened copper surface. Two surfaces were fabricated via identical laser etching of copper samples. Pool boiling experiments were carried out on each sample; one reference sample was tested in DI water, while the second one was tested in the Cu-water nanofluid to deposit a thin layer of nanoparticles. The samples were characterized by scanning electron microscopy (SEM), 3D profilometry, and static contact angle measurements to analyze the morphological and wettability characteristics before and after the nanoparticle deposition. The coated sample was then tested with pure DI water to assess the effects of the nanoparticle coating on the boiling performance of the surface and to investigate the stability of the coating. An enhancement of the critical heat flux (CHF) by 27% was measured and the SEMs confirmed that the thin nanoparticle coating survived multiple boiling tests, including one test carried out up to CHF. This study demonstrates that nanofluid boiling can be used as a deposition technique to realize stable coatings for enhancement of CHF using pure fluids in the absence of nanoparticles