.pe / Peo / Pvc Drag Reduction Of Composite Materials And Performance Testing,

Fluid-frictional drag retards the development of underwater weapon to a fast and low noise level, such as submarine and torpedo. In this paper, poly (ethylene oxide) (PEO) drag reduction composite materials, composed of low-density polyethylene, polyvinyl chloride and poly (ethylene oxide), were designed and prepared based on the drag reduction characteristics of PEO dilute solution.A high-precision rotating disc-drag tester with accuracy of ±0.001N·m was designed, which was used to study the drag reduction rule of polymer diluted solution, coatings, elastic materials and drag reduction composite materials. It could induce a high Reynolds Number (N_Re) turbulent flow and measure the fluid-frictional drag. Drag reduction characteristics and influence factors of PEO dilute solution and drag reduction composite materials were investigated by this apparatus. Effect of composition on mechanical property, microstructure and drag reduction efficiency (DR) was investigated by mechanical properties testing, infrared spectroscopic analysis and SEM.The results showed that, for PEO dilute solution, drag reduction was not significant when N_Re was below 4.5×10⁵. The best drag-reduction efficiency of 35% was obtained when was in the range of 6～8×10⁵. DR decreased when N_Re exceeded 9×10⁵. The largest DR was obtained at concentration of 100ppm, which was in the range of 22%³6%. So critical Reynolds Number and critical concentration existed, which was determined by polymer molecular weight. The more molecular weight, the higher crictical N_Re and the lower crictical concentration was.The maximum DR of drag reduction composite reached to 41%. It exceeded 30% when N_Re was in the range of 4～8×10⁵. PEO was responsible for the drag reduction, and a given amount of PVC can improve drag reduction performance at high N_Re. Excessive PEO and PVC debased mechanical properties. After immersed in water, fluid-frictional drag of composite was reduced due to PEO dissolved and adhered to specimen surface. Furthermore, many finely porous appeared on specimen surfaces and a film was formed after natural drying. However, the drag-reduction efficiency decreased owing to PEO lost from composite materials after immersed in water for a long time.