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ACRC Contract Report 54PDF


Title:An Experimental Investigation of Pressure Drop and Heat Transfer in an In-Tube Condensation System of Ammonia with and Without Miscible Oil in Smooth and Enhanced Tubes
Author(s):Komandiwirya, H.B.; Hrnjak, P.S.; Newell, T.A.
Subject(s):heat transfer
pressure drop
Abstract:Measurements of pressure drop and heat transfer coefficient were taken for smooth and internally enhanced smooth sections. Pure ammonia was used in both smooth and enhanced tubes, whereas ammonia mixed with oil only used in smooth tubes. The inside diameter of the tubes are 8.1 mm. The mass fluxes were varied from 20 to 270 kg/m2-s (15 to 1999 klbm/ft2-hr) and inlet quality was varied from 0 to 95%. The test section heat fluxes ranges from 2.0 to 10.0 kW/m2 (635 to 3175 Btu/ft2-hr). The majority of data points were taken at inlet refrigerant temperature of 35°C (95°F). The data is then compared to several pressure drop and heat transfer correlations to understand the characteristic of the test sections. Experimental data shows variation along the circumferential of the test section, which will be discussed more thoroughly. Oil has effects of lowering the heat transfer coefficient and increasing the pressure drop. Microfin tube has positive and negative effects on the heat transfer coefficient, depending on the fin height.
Issue Date:2005-04
Publisher:Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign.
Series/Report:Air Conditioning and Refrigeration Center CR-54
Genre:Technical Report
Date Available in IDEALS:2009-08-06

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