Effect of Polymers on Transient Reynolds Number Change in Pipe Flow and Reduction of their Coefficient of Friction

There are many ways to reduce the coefficient of friction as a result of pressure drop in internal flows and thrust force in external flows. For example, film suction, injection of gas bubbles in the boundary layer, use of magnetic fluid, etc., which are mostly intermediate fluids. Polymers are among the materials that can be used as intermediate fluids. Due to their ring structure and chain structure, polymer particles stretch and elongate when they are inside the stream. This stretching first absorbs energy from the fluid and does not allow this energy to be used to produce vortices. Second, stretching the polymer chain like a wall prevents the growth of vortices. The higher the molecular mass of the polymer, the greater the drop loss and the lower the critical concentration due to the heavier the polymer. As the concentration of polymer in water increases, the drop curve in terms of discharge towards the horizontal axis of Shifa and gets closer to it. In other words, the friction drops decreases. Percentage drop for ۱۰۰gr per cubic meter of water is ۴.۵۴%, ۲۰۰gr per cubic meter is ۱۲.۷۸%, ۳۰۰gr per cubic meter is ۲۷%, ۴۰۰gr per cubic meter is ۳۰.۷% and ۵۰۰gr per cubic meter is ۳۹.۴%, the maximum amount of reduction is.

Keywords:

coefficient of friction , Polymer , concentration , Fluid