Void fraction, pressure drop, and oil holdup measurements were taken for smooth,axially grooved, and 18?? helically grooved horizontal tubes in evaporation. All threecopper test sections had an outer diameter of9.53 mm (3/8"). R134a was used in thisexperiment in combination with ICI's EMKARATE RL32S Polyol Ester (POE) oil. Datawas taken at various operating conditions with mass fluxes ranging from 75 to 500kg/m2s (55 - 367 klbm/ft2hr), test section inlet qualities of 10 to 70%, test section heatfluxes from 0 to 10 kW/m2, and loop oil concentrations varying from approximately 0.2to 6% oil. All tests were run with a test section inlet temperature of 5??C (41??F).Data collected from these tests will be presented in this thesis. Void fraction andpressure drop measurements will also be compared to models developed for purerefrigerants in order to help better understand the effect of oil in refrigerationapplications.
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