Numerical analysis of flow patterns maps in horizontal pipes with variation of inclination angles in a collector/evaporator of a DX-SAHP

Abstract This research describes the flow pattern maps of R600a that were generated in a horizontal pipe with different inclination angles in a collector/evaporator of a DX-SAHP. The solar flat-plate collector dimensions were 3.8 and 1000 mm of internal diameter and length, respectively. The influences of mass velocities, heat flux and inclination angles were analyzed. Five experimental tests were carried out with inclination angles between 10 and 45°, mass velocities between 203.24 and 222.28 kg·m−2·s−1, solar heat flux values of 200.58 and 507.23 W·m−2 were used. The numerical analysis was carried out based on the correlations proposed by Kattan and Kundu, in addition, a flow pattern map for horizontal pipes without inclination is shown, under Wojtan's mathematical model, thus indicating the difference when working with pipes in similar conditions by varying their inclination in capture to incident solar radiation. Results obtained present flow pattern maps where six zones can be seen: intermittent, annular, mist, slug, stratified, wavy stratified.