Effects of oil on boiling R-123 and R-134a flowing normal to an integral-finned tube bundle

Local, experimental heat transfer coefficients have been measured for boiling refrigerant flowing up and across a tube bundle segment representing a full flooded evaporator tube bundle. R-123 and R-134a data with 26 fins per inch (1024 fins per meter) tubes have been obtained. The refrigerant enters...

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Bibliographic Details
Published in:ASHRAE transactions 1999-01, Vol.105, p.478-490
Main Authors: Tatara, Robert A, Payvar, Parviz
Format: Article
Language:English
Subjects:
Boiling liquids
Evaporators
Flow of fluids
Heat flux
Heat transfer coefficients
Refrigerants
Temperature measurement
Tubes (components)
Vapors
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Summary:Local, experimental heat transfer coefficients have been measured for boiling refrigerant flowing up and across a tube bundle segment representing a full flooded evaporator tube bundle. R-123 and R-134a data with 26 fins per inch (1024 fins per meter) tubes have been obtained. The refrigerant enters at 15% vapor quality and exits at nearly 100% vapor in order to simulate an actual flooded evaporator bundle. The nominal area heat flux was varied from 2,607 to 10,427 Btu/h times ft super(2) (8,224 to 32,893 W/m super(2)) as the tube bundle oil content ranged from 0 to 15% (by weight) for each refrigerant /tube combination. The performance of R-22 without oil has also been determined. Local tube and bulkfluid temperatures were measured directly by thermocouples to calculate the refrigerant-side heat transfer coefficients. The bundle segment saturation temperature set point (taken at the top of the tube bundle) is 40 degree F (4.4 degree C).
ISSN:0001-2505