Re-evaluation of Hazen-Williams Coefficient <i>C</i> of Pipeline (I)

There are two types of mean flow velocity formulas for pipes, the Darcy-Weisbach equation and Hazen-Williams equation. In process deriving from equation, it was clarified that friction loss coefficient f is expressed by exponential function ＝ aRe-b. Next, C obtained eliminating effect Reynolds number Re. It confirmed only constant a remained in there almost no influence water temperature viscosity, meanings constants b were considered. When designing pipeline, relative roughness k/D on inner surface pipe evaluated using Colebrook order to set transition section which both effects viscosity effective as design range. The relationship between these hydraulic f, C, Re verified Moody chart, issues raised design.