Heat transfer and pressure drop of two-phase flow in an inclined annular channel

The phenomena of two-phase flow through horizontal, vertical and inclined tubes has many engineering applications in heat exchangers, boilers, nuclear reactors and refrigerators respectively. In the present investigation, two-phase flow heat transfer and pressure drop have been experimentally studied at different orientations of an annular channel test section subjected to uniform heat flux. The annular test section was internally heated by a D C power supply. The experimental investigation been classified into three steady state groups of (heat flux, mass flux, and inlet temperature). The first one was at 522.41 kw/m2, 310 kg/m2s and 89.4 degree C, the second was at 779.72 kw/m2, 507 kg/m2s and 94.3 degree C and the third was at 1019.97 kw/m2, 701 kg/m2s and 100 degree C. The experimental results included the variation of both the wall temperature and the local heat transfer coefficient distributions with the inclination angle of the annular rest section. The effect of inclination on the two-phase heat transfer coefficient and pressure drop are presented and discussed. The present experimental results are compared with some existing correlations for two-phase flow boiling heat transfer in horizontal and vertical tubes at their range of validity. The comparison shows a good agreement. The behavior of the two-phase mean heat transfer coefficient shows an enhancement due to inclination from horizontal to vertical orientation. The enhancement factor relating the two-phase heat transfer coefficient with the inclination angle is predicted. d.1 tabs., 4-13 figs., 32 refs