Convective boiling of R-407c inside horizontal microfin and plain tubes

摘要

This work presents experimental results on the nucleate and convective boiling of R-407c, flowing with a mass velocity in the range 200-300 kg m(-2) s(-1), at 770 kPa, inside horizontal plain and microfin tubes with outside diameters (OD) of 7.0 and 12.7 mm. The data are presented for heat fluxes of 10 and 20 kW m(-2). The experimental data are discussed in terms of the heat transfer coefficient and the pressure drop as a function of the vapor quality. For a heat flux of 10 kW m(-2) and a mass velocity of 200 kg m(-2) s(-1), the dominant heat transfer mechanisms for the 7 turn OD tube is the nucleate boiling regime whereas for the 12.7 mm OD tube it is the convective boiling regime. (C) 2003 Elsevier Science Inc. All rights reserved. [References: 29]