基于PIV与数值模拟的聚丙烯酰胺溶液圆管湍流减阻特性研究OA

Addressing the high-energy-consumption issue caused by turbulence in fluid pipeline transportation,this study introduces polyacrylamide drag-reducing agents into the flow field.By combining numerical simulation and particle image velocimetry(PIV)experiments,the influence of the drag-reducing agent on the turbulent drag reduction characteristics in a circular pipe is investigated,and the intrinsic relationship between the drag reduction performance and the flow field structure is revealed.After comparing three low-Reynolds-number k-ε models,the Lam-Bremhorst model was selected for its simulation accuracy above 96.56%.Results indicate that DRA addition thins the near-wall boundary layer,enhancing flow performance and suppressing turbulence.In the flow rate range of 5.7～13.7 m³/h,drag reduction reaches 30%～40.9%,centerline flow velocity increased by 2.97%～2.24%,turbulence intensity decreases by 3.86%～3.81%,and near-wall turbulent dissipation drops by 45.2%～28.6%.Mechanistic analysis shows that polyacrylamide molecules generate elastic stress in the near-wall region.This both suppresses turbulent coherent structures and kinetic energy fluctuations,and thins the boundary layer while improving the velocity profile,thereby reducing flow resistance.The study provides a theoretical basis for understanding the near-wall action mechanism of DRAs and for improving energy efficiency in pipeline flow.