Estudo da redução de arrasto induzido por polímeros em escoamentos internos turbulentos em dutos

Abstract

The flows turbulent and laminar are present in various applications of engineering and one of the villain of energy loss big is the surface friction. Currently, there are several research aimed for the study of reducing drag (DR) with the objective of developing effective methods to reduce the friction. Regardless of numerous research carried out until today, the phenomenon DR still remains in study not it is fully understood. This paper studied the drag reduction by polymer induction in turbulent internal flows in ducts. We constructed a testing bench to perform the analysis of drag reduction, the bench has basically two manometers with a 8.5 psi full scale, a peripheral pump 0.5 HP, an acrylic tank, valves and tubes pvc and is situated in the Laboratory Fluid Mechanics UFRN. Were used as polymer additives to polyethylene glycol 4000, the Polyox WSR N60K, Polyox WSR 301 and Polyox WSR 205. The rationale for the choice of these polymers is their wide application in situations requiring greater energy efficiency, such as the addition reducing polymers for the jet used by the fire department to achieve greater distances. The induced drag reduction polymers is investigated from the turbulent flow analysis, with Reynolds number in a range between 2×104 𝑒 5×104. The part of the first pressure measurement analysis on two points of the turbulent flow, then the density measurements, viscosity of the polymer solutions and culminates in drag reduction calculation, allowing to analyze the influence of the addition polymer in reducing the drag in turbulent flows. The Polyox WSR N60K, the Polyox WSR 301 and Polyox WSR 205 decreased drag highlighting the Polyox WSR 301 that showed the greatest reduction among the polymers studied, which concluded that the Polyox WSR 301 is more efficient to drag reduction in pipes. There was no drag reduction in polyethylene glycol 4000 to the measured concentration.