Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

The effect of oil contamination on the nucleate pool-boiling performance of R-114 from a porous-coated surface

Conference · · ASHRAE Trans.; (United States)
OSTI ID:6515762
The external, nucleate pool-boiling heat-transfer coefficient in R-114 with up to 10% oil (by mass) was measured on a smooth copper tube and on a porous-coated copper-nickel tube. The heat flux was varied from 160 to 30,000 Btu/hr . ft/sup 2/ (0.5 to 95 kW/m/sup 2/) at boiling temperatures of 28 F and 44 F (-2.2/sup 0/C and 6.7/sup 0/C). The porous-coated surface was found to improve the heat-transfer coefficient over the smooth surface by a factor of 7 to 10 in oil-free R-114. The presence of up to 3% oil caused about a 35% reduction in the heat-transfer coefficient of the porous-coated surface at all heat fluxes. With 6% or more oil, the boiling performance of this surface declined drastically at heat fluxes in excess of 9500 Btu/hr . ft/sup 2/ (30 kW/m/sup 2/). Some plausible mechanisms to explain the observed behavior are described.
Research Organization:
Dept. of Mechanical Engineering, Naval Postgraduate School
OSTI ID:
6515762
Report Number(s):
CONF-8606125-
Conference Information:
Journal Name: ASHRAE Trans.; (United States) Journal Volume: 92:2B
Country of Publication:
United States
Language:
English