Dropwise condensation of steam on ion implanted titanium surfaces

• Published in: International journal of heat and mass transfer Vol. 53; no. 1; pp. 423 - 430
• Main Authors: Rausch, M.H., Leipertz, A., Fröba, A.P.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15-01-2010; Elsevier
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Dropwise condensation; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Heat transfer; Heat transfer coefficient; Ion implantation; Nucleation; Phase transitions and critical phenomena; Physics; Solid surfaces and solid-solid interfaces; Surface free energy; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Theoretical studies. Data and constants. Metering; Titanium; Titanium; Ion implantation; Nucleation; Heat transfer coefficient; Dropwise condensation; Surface free energy; Surface preparation; Experimental study; Free energy; Surface energy; Heat transfer
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2009.09.014

Stable dropwise condensation of steam was achieved by ion beam implantation of N
+ on titanium surfaces stabilized by a preoxidation procedure. It is pointed out that dropwise condensation can be adjusted by ion implantation in spite of increased wettability indicated by contact angle and surface free energy measurements. Our results suggest a nucleation mechanism possibly caused by interactions of nano-scale surface roughness and surface chemistry effects connected with precipitation of nitrides. Measured heat transfer coefficients for dropwise condensation were up to 5.5 times larger than values calculated by Nußelt film theory. No significant influence of the applied ion implantation parameters was found.