Abstract
This paper presents experimental investigations conducted to understand the influence of water-soluble drag-reducing polymers (DRPs) in single- and two-phase (stratified wavy) flow on flow-field characteristics. These experiments have been presented for water and air–water flowing in a horizontal polyvinyl chloride 22.5-mm ID, 8.33-m long pipe. The effects of liquid flow rates and DRP concentrations on streamlines and the instantaneous velocity were investigated by using particle image velocimetry (PIV) technique. A comparison of the PIV results was performed by comparing them with the computational results obtained by fluent software. One of the comparisons has been done between the PIV results, where a turbulent flow with DRP was examined, and the laminar–computational fluid dynamic (CFD) prediction. An agreement was found in the region near the pipe wall in some cases. The results showed the powerfulness of using the PIV techniques in understanding the mechanism of DRP in single- and two-phase flow especially at the regions near the pipe wall and near the phases interface. The results of this study indicate that an increase in DRP concentrations results in an increase in drag reduction up to 45% in single-phase water flow and up to 42% in air–water stratified flow.