keywords: Drag reduction, Drag reducing polymer, pipe diameter, polyethylene oxide
This study was carried out to investigate the effect of pipe diameter and temperature on the effectiveness of polyethylene oxide as drag reducing polymer. The flow facility is made from unplasticized polyvinyl chloride (uPVC) pipes of 20 and 12 mm internal diameter (ID), Temperature range of 5 to 60oC, polymer concentration of 5 to 50 ppm and Reynolds numbers less than 100000 were studied using oil [diesel] (density = 832 kg/m3, viscosity = 1.664 mPa.s at 25oC) and water (density = 1000 kg/m3, viscosity = 0.91 mPa.s at 25oC) as test fluids. Pressure drop was measured using u-tube manometer. In single phase (water) flow, a maximum drag reduction of 72% (20 mm ID), 76% (12 mm ID) was achieved in horizontal flow at room temperature. Drag reduction decreased from 80.61 to 60% (20 mm ID), 84 to 66.8% (12 mm ID) when temperature was raised from 5 to 60oC. In multiphase flow, a maximum drag reduction of 62.25% (20 mm ID), 65.25% (12 mm ID) (25% oil input, Umix=1.68 m/s, room temperature) was observed. The result show that as temperature increased from 5 to 60oC, drag reduction decreased from 70.83 to 50% (20 mm ID), 73.08 to 54.62 (12 mm ID). Thus, temperature has significant effect on drag reduction but its effect is sparingly higher for the larger pipe diameter.