Head losses and friction factors of steady turbulent flows in plastic pipes

Abstract

Many hydraulic engineering applications, which were once limited to the use of traditional materials, are progressively executed using prefabricated plastic pipes, particularly in the case of larger diameters. There is relatively little information specifically on the laws of flow resistance in plastic tubes, or that has been obtained directly for these materials. In this work, head losses and friction factors were determined experimentally in turbulent steady water flows established in conduits made of different plastics. Several pressure pipes, governed by gravity and forced, with nominal diameters until 110 mm, were used with Reynolds numbers ranging from 4E3 to approximately 6E5. Pairs of values, friction factor vs. Reynolds number, were computed and plotted using logarithmic scales. The layout of the points seems to be generally well represented by the Colebrook-White equation, for each relative roughness. Important absolute roughness variations for the different pipes were found by trend analysis. Blasius and Scimemi empirical formulas for smooth pipes were also plotted and also showed a satisfactory agreement with the experimental data, for Re up to 1E5 and a little less than 1E6, respectively.