TO-98-03-4 -- Heat Transfer Characteristics and Correlations for R-410A Flowing Inside a Horizontal Smooth Tube PDF

This study was carried out to provide data on heat transfer coefficient and pressure drop for R-410A flowing inside a horizontal smooth copper heat transfer tube and also to obtain the empirical correlations of the heat transfer coefficient and pressure drop for R-410A to design the heat exchanger installed in an air conditioner. In the present experiments, a horizontal copper smooth tube with an outside diameter of 7.0 mm (2.2 in.) was employed, and the measurements of local heat transfer coefficient and pressure drop for R-410A, including R-407C and R-22, were made under the practical evaporation and condensation conditions of the air conditioner. In order to obtain the correlations, the experimental results of heat transfer coefficients were compared with the existing correlations, while the new correlations of two-phase friction multipliers for evaporation and condensation pressure drops were developed in this investigation. Since good agreement between the experimental data for R-410A and the existing correlations was shown for both evaporative and condensing heat transfer coefficients and the pressure drop data were also well correlated by the present unique equations, the correlations proposed in this investigation on heat transfer coefficient and pressure drop are applicable to designing a heat exchanger using R-410A.

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