Paul Onubi Ayegba
Ahmadu Bello University
Title: Drag Reduction by Additives for Two-Phase Oil-Water Flow in and around 180o Bends
Biography
Biography: Paul Onubi Ayegba
Abstract
This study investigates the effect of U-bend on polymer drag reduction (DR) and flow patterns for oil-water flows. The test section consisted of 19-mm ID clear polyvinyl chloride (CPVC) straight pipes and U-bend (R = 100 mm). Measurements were carried out under different flow conditions at hydrodynamically developed flow section before the bend, in the bend and at two redeveloping flow sections after the bend. Observed flow patterns at various test sections were similar though mixture velocities at transition sometimes varied between the test sections. In general, the addition of polymer imposed partial or complete flow stratification. Pressure losses differed at the various test sections and this difference was strongly related to the superficial velocity of the phases and flow patterns. At high mixture velocities, pressure losses at the redeveloping section after the bend were higher than those at other two sections while at low mixture velocity, they were higher at the bend than in the straight pipe sections. DR at all test sections generally increased with water superficial velocity and reduced with oil fraction in the region of strong turbulence. At high mixture velocities, DR upstream of the bend was highest while the least was recorded at the bend. A reverse behaviour was recorded at low mixture velocities. The highest DR upstream of the bend, in the U-bend and at the two downstream redeveloping sections were 40% (USO = 0.12 ms-1), 34% (USO = 0.48 ms-1), 28% (USO = 0.12 ms-1), and 29% (USO = 0.12 ms-1) respectively.