An Experimental Study of Dropwise Condensation on Vertical Discs.

Abstract

Three hydrophobic coating systems were tested for their ability to promote permanent dropwise condensation of steam at 21 KPa (3 psia). The coatings used were: (1) Nedox, a Teflon coating that uses a porous nickel substrate to improve adhesion, (2) Sputtered Teflon, and (3) C-6 fluoroepoxy, a protective coating developed for naval aircraft. Copper-nickel discs, 32 mm in diameter, were tested with all three coatings. In addition, copper and titanium discs were tested with the sputtered Teflon coating. Coating thickness was varied from 0.08 to 25.0 microns. The coatings tested provided only moderate improvements in heat transfer. The 0.08 micron coating of sputtered Teflon on copper-nickel provided only a 58% improvement in the heat transfer coefficient over filmwise. A chemically promoted specimen tested in the same experimental apparatus gave a 500% improvement in the heat transfer coefficient. All coatings tested showed surface deterioration after two to ten hours of testing, and none would be considered a practical permanent promoter of dropwise condensation. (Author)

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1979
Accession Number
ADA085052

Entities

People

  • Kevin Patrick Perkins

Organizations

  • Naval Postgraduate School

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies
  • Weapons Technologies

DTIC Thesaurus Topics

  • Chemistry
  • Coatings
  • Coefficients
  • Condensation
  • Diameters
  • Energy
  • Heat Energy
  • Heat Transfer
  • Heat Transfer Coefficients
  • Measurement
  • Physical Properties
  • Plastic Explosives
  • Surface Temperature
  • Temperature Gradients
  • Thermal Conductivity
  • Thermophysical Properties
  • Thickness

Readers

  • Combustion and Flow Dynamics.
  • Surface Coatings Technology.
  • Surface Engineering/Surface Coating Technology.