Laith Jaafer Habeeb^1,, Riyadh S. Al-Turaihi²

Experimental and numerical studies are investigated to study the two-phase flow phenomena around multi- shape obstacles in a rectangular enlarging channel which has the dimensions (10 × 3 × 70 cm) enlarged from assembly circular tube of the two phases. Experiments are carried out in the channel with air-water flow with different air and water flow rates. These experiments are aimed to visualize the two phase flow phenomena as well as to study the effect of pressure difference through the channel with the existence of the obstacle. All sets of the experimental data in this study are obtained by using a pressure transducer and visualized by a video camera for different water discharges (20, 25, 35 and 45 l/min) and different air discharges (10, 20, 30 and 40 l/min). While the numerical simulation is conducted by using commercial Fluent CFD software to investigate the steady and unsteady turbulent two dimensional flows for different air and water velocities. The results showed that when air or water discharge increases, high turbulence is appear which generate more bubbles and waves and the mean pressure difference increases. Also, in a water slug, bubbles move slower than the liquid.

steady and unsteady flow, smooth enlargement, two-phase turbulent flow, multi- shape obstacles in channel, experimental and Fluent CFD software investigation