Characteristics of evaporation of propane (R290) in compact smooth and microfinned tubes

Abstract

Evaporation of flowing propane and the effect of enhanced geometry on heat transfer coefficient and pressure drop is experimentally investigated. One smooth tube and two microfinned tubes with an outer diameter of 5 mm were tested. Heat transfer coefficient and pressure drop were determined for saturation temperatures of 0, 5 and 10 °C for smooth tube, and the effect of using tubes with enhanced geometries was evaluated at heat fluxes ranging between 15 and 33 kW m−2 and mass fluxes between 250 and 500 kW m−2 s−1. The increase of heat transfer coefficient for microfinned tubes relative to smooth tube diminishes with increasing mass flux, while the increase of pressure drop remains unaffected. Comparison of the experimental results with correlations for prediction of pressure drop and heat transfer coefficient demonstrates availability of reliable correlations. Nevertheless, correlations show considerable divergence in accuracy for different microfinned tubes.