Open AccessInfluencing factors on flow boiling of carbon dioxide in enhanced tubes and comparison with correlations
Author(s) -
R. Mastrullo,
A.W. Mauro,
John R. Thome,
Giuseppe Peter Vanoli,
Luca Viscito
Publication year - 2020
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1599/1/012010
Subject(s) - refrigerant , thermodynamics , boiling , carbon dioxide , refrigeration , heat transfer , heat transfer coefficient , materials science , boiling heat transfer , flow (mathematics) , boiling point , mechanics , working fluid , mechanical engineering , chemistry , nucleate boiling , heat exchanger , engineering , physics , organic chemistry
Carbon dioxide two-phase flow characteristics are different from those of conventional refrigerants, due to the CO 2 particular thermodynamic and transport properties obtained by working at high reduced pressures. Moreover, the use of peculiar heat transfer surfaces such as grooves and internal fins are often preferred to enhance the boiling heat transfer performance. This paper collects CO 2 flow boiling heat transfer coefficient data from different independent databases available in scientific literature, regarding both smooth and enhanced geometries and a wide range of operative conditions, that are typical of refrigeration systems and heat pumps. The database for enhanced tubes covers internal diameters from 0.8 to 8.92 mm, saturation temperatures from -30 to +20 °C, imposed heat fluxes from 1.67 to 60 kW/m 2 and mass velocities from 75 to 800 kg/m 2 s, collecting more than 800 points. Heat transfer data for smooth and enhanced surfaces under the same conditions are collected, in order to measure the enhancement and to correlate it to the geometry augmentation. The assessment of quoted prediction methods explicitly developed for carbon dioxide is finally carried out, with a proposal for a correction factor.