Document Type : Full length


Razi University


Decreasing pressure losses in microtubes is an important subject, especially when increase in flow capacity is required. In the same pumping power, decreasing the pressure drops is coincides with increasing the fluid flow rate passing through a microtube. The current study aims to examine how the water pressure drop across a microtube can be affected by the addition of small concentrations of different drag-reducing polymeric agents. A kind of laminarization behaviour was found by the addition of the selected polymer to the turbulent flow. The effect of concentration of drag-reducing agent (DRA) on observed viscosity and drag values are reported. Moreover, the effects of different types of drag-reducing agents on friction factor are obtained at the best concentration in the range of examined concentrations. Under this condition amount of drag reduction percentage and increase in capacity of the flow were respectively 33% and 36%. The obtained results show that more drag reduction occurs at a higher flow rate for 20ppm of high molecular weight polyacrylamide.