Accession Number:

ADA155609

Title:

The Influence of Oil Contamination on the Nucleate Pool-Boiling Behavior of R-114 from a Structured Surface.

Descriptive Note:

Master's thesis,

Corporate Author:

NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s):

Report Date:

1985-03-01

Pagination or Media Count:

124.0

Abstract:

The U.S. Navy currently uses refrigerant R-114 in centrifugal chilled-water air-conditioning plants aboard submarines and surface ships. The Navy hopes to reduce the size of these units and increase their performance by using enhanced evaporator and condenser surfaces. The external nucleate pool-boiling heat-transfer coefficient of a horizontal smooth copper tube in R-114-oil mixtures 0 to 10 percent oil was measured for heat fluxes from 1 to 100 kWsq m at two different saturation temperatures -2.2 C and 6.7 C. A copper-nickel tube coated with the Union Carbide High Flux coating was similiarly tested. The High Flux coating was found to improve the heat-transfer coefficient by at least a factor of 7 in oil-free R-114. Oil resulted in about 20 percent reduction of the heat transfer coefficient of the High Flux surface at heat fluxes less than 30 kWsq m and up to an 80 percent reduction at heat fluxes above 30 kWsq m with greater than 6 percent oil. Under all conditions, the High Flux coated tube outperformed the smooth copper tube. Keywords Heat transfer enhancement Porous-coating enhanced surfaces. Theses.

Subject Categories:

  • Air Conditioning, Heating, Lighting and Ventilating
  • Thermodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE