Discussion of formula selection of friction head loss in FRP pipe

As for the calculation of friction head loss in the FRP pipe,based on the hydraulics principle,several formulas were compared and the rationality of Hazen-Williams formula was demonstrated,and the relevant parameters were modified.The study adopted different formulas to calculate the water head loss in the case of small-trough inverted siphon in Xinjiang.The results of the comparison between the calculated and observed head loss suggested that:(1)Hazen-Williams formula can be used in the friction head loss calculation in the FRP pipe with diameter less than 2 000 mm,and the frictional coefficient needs to be modified;and(2)the combination of JiEn formula and Darcy formula can be used in the friction head loss calculation in the FRP pipe with diameter larger than 2 000 mm.