Article ID Journal Published Year Pages File Type
651618 Experimental Thermal and Fluid Science 2014 9 Pages PDF
Abstract
Experiments to measure flow boiling heat transfer coefficients and pressure drops of R134a and R407C inside a smooth horizontal tube (9.52 mm outside diameter, 1.2 m length) were performed at a refrigerant mass flux range of about 100-400 kg/m2 s varying the inlet temperature of the evaporator within the range of 5-9 °C, with heat fluxes within the range 3-10 kW/m2. The experimental data are described in terms of the heat transfer coefficients and pressure drop gradient as a function of the vapor quality. The experimental results clearly show that the heat transfer coefficients of R134a are always higher than those of R407C (for a minimum of +55% to a maximum of +87%) for same operating conditions. Furthermore, an assessment of predictive methods is provided for heat transfer coefficients and pressure drop gradients; also a comparison of flow regimes visualizations for R134a with a flow pattern map available in the literature has been presented.
Related Topics
Physical Sciences and Engineering Chemical Engineering Fluid Flow and Transfer Processes
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