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Experimental Study on Evaporation Heat Transfer and Oil Effect in Micro-fin Tube Using $CO_2$  

Lee, Sang-Jae (Department of Mechanical Engineering, Hanyang University)
Choi, Jun-Young (Korea Testing Laboratory)
Lee, Jae-Heon (Department of Mechanical Engineering, Hanyang University)
Kwon, Young-Chul (Department of Mechanical Engineering, Sunmoon University)
Publication Information
Korean Journal of Air-Conditioning and Refrigeration Engineering / v.20, no.2, 2008 , pp. 106-112 More about this Journal
Abstract
In this paper, the experimental results on evaporation heat transfer characteristics were reported for a micro-fin tube using $CO_2$. An experimental refrigerant loop had been established to measure the evaporation heat transfer coefficient and pressure drop of $CO_2$. Experiments were conducted for mass fluxes, heat fluxes, saturation temperatures and PAG oil concentrations. With increasing the heat flux and the saturation temperature, the evaporation heat transfer coefficient increased. At the higher mass flux, however, the exit vapor quality of the micro-fin tube was to be lower. The peak of the heat transfer coefficient was shifted toward low quality region. The evaporation pressure drop increased as the mass flux increased and the saturation temperature decreased. As PAG oil concentration increased, the evaporation heat transfer coefficient decreased and the dryout was delayed by oil addition.
Keywords
Carbon dioxide; Evaporation heat transfer; Oil effect; Micro-fin tube; Dryout;
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