Nucleate Pool Boiling Performance of Smooth and Finned Tube Bundles in R-113 and R-114/Oil Mixtures
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
Pagination or Media Count:
Heat-transfer measurements were made for boiling of refrigerants and refrigerantoil mixtures from smooth and finned tube bundles. The bundles contained 15 heated tubes arranged in an equilateral triangular pitch of 19.1 mm. The outside diameter of the smooth tubes 15.8 mm was equal to the diameter to the tip of the fins of the finned tubes. The smooth tube bundle was tested in pure R-113 with varying surface histories as well as tested in pure R-114oil mixtures. The finned tube bundle was tested in pure R-114oil mixtures. Oil concentrations used were 1, 2, 3, 6, and 10 by mass. The majority of data sets were taken with decreasing heat flux where hysteresis is normally not seen as shown in present experiments when using the simulation heaters. The addition of oil to the smooth tube bundle showed heat-transfer performance to increase over that measured with pure R-114 up to a 6 concentration. The maximum enhancement in heat-transfer performance of the smooth tube bundle was around 44 with R-114 and 2 oil. Performance was only slightly degraded from the case of pure R-114 at the maximum oil concentration of 10. Heat-transfer performance was more than doubled for the finned tubes when compared to that for the smooth tubes. Addition of oil to a concentration of 3 by mass, yielded a maximum increase in finned-tube performance of 22 over that measured with pure R-114. Theses.
- Air Conditioning, Heating, Lighting and Ventilating