4678 – Convective Evaporation on Plain Tube and Low-Fin Tube Banks Using R-123 and R-134a PDF

This experimental study investigates the convective evaporation heat transfer in a tube bundle. Heat transfer experiments were performed using R-134a and R-123 on a plain tube and a fin tube having 15.9 mm (0.626 in.) O.D. over a range of vapor qualities (0.03~0.34) with low mass velocities (8 to 40kg/m²s, or 1.6 to 8.2 lbm/ft²s) for a wide range of heat flux. Pool boiling data were also tested in the same apparatus. The fin tube having fins 0.6 mm (0.024 in.) high, with 0.6 mm (0.024 in.) fin pitch and 0.3 mm (0.012 in.) fin thickness, results in up to 170% boiling performance enhancement over the plain tube.

The present experimental data were compared with correlations using superposition and asymptotic models. The superposition-type correlation provided better prediction than the asymptotic model.

Units: Dual