Effect Of 180° Bends On Gas/liquid Flows In Vertical Upward And Downward Pipes
Free (open access)
435 - 445
A. Almabrok, L. Lao & H. Yeung
Experimental investigation has been carried out on upward and downward vertical pipes with 180° bends to study gas-liquid two-phase flow behaviours in pipes with serpentine configuration. Wire mesh sensor (WMS) is installed at top and bottom positions of upward and downward sections in order to identify the void fraction distributions. Film thickness probes are employed to obtain circumferential profile of the liquid film thickness at different axial positions along both sections. Further features such as flow patterns are identified by examining the time trace and probability density function (PDF) data. All measurements are conducted for different superficial gas velocities, while superficial liquid velocity is fixed at 1.0 m/s. The study identified that the centrifugal force present in 180° bends caused a flow maldistribution in the adjacent straight sections. It is noted from the time trace and PDF results that the superficial gas velocity has obvious effects on the flow development along different positions of the pipes, where the flow regime varied over whole velocity ranges tested. These results are confirmed by the cross-sectional view and sliced stack images (longitudinal view) of the void fraction distributions. The results also showed that the flow behaviour in upward and downward pipes is affected by bends, although to varying degrees. Keywords: upward, downward, 180° bends, film thickness probes, WMS.
Keywords: upward, downward, 180° bends, film thickness probes, WMS.