How do you find the friction factor of a pipe?

The friction factor for laminar flow is calculated by dividing 64 by the Reynold’s number.

What is nikuradse equation?

The Nikuradse-Prandtl-von Karman (NPK) equation is the most widely used expression to determine friction factors for fluid flow in smooth pipes [1–3]. It implicitly relates the friction factor (expressed here as f; sometimes called λ) to the Reynolds number, Re. It is shown in Equation (1).

What is the formula for friction factor f?

Friction factor, f, in equations (13) and (14) is calculated for streamline flow (Re less than 2000) from the relationship f = 64/Re (minimum value = 0.035 at 2000 Re).

What is the Darcy Weisbach formula for head loss due to friction?

In fluid dynamics, the Darcy–Weisbach equation is an empirical equation, which relates the head loss, or pressure loss, due to friction along a given length of pipe to the average velocity of the fluid flow for an incompressible fluid. The equation is named after Henry Darcy and Julius Weisbach.

How is the friction factor of a commercial pipe determined?

In the transition region where the friction factor depends on both Reynolds number and the relative roughness (ε/D), the friction factor of the commercial pipe is found to be different from those obtained from the sand roughness used by Nikuradse (see Figure 2 ).

How is the friction factor for turbulent flow calculated?

The friction factor for turbulent flow is calculated using the Colebrook-White equation: Due to the implicit formation of the Colebrook-White equation, calculation of the friction factor requires an iterative solution via numerical methods.

When did Nikuradse calculate the friction factor in rough pipes?

1 ==                                                          (1) The development of approximate equations, for calculations of friction factor in rough pipes, began with Nikuradse’s turbulent pipe flow investigations, in 1932. and 1933.  The results of his experiments are shown in figure 1.

How is the friction factor of laminar flow calculated?

For laminar flow (Re < 2100), the friction factor was independent of the surface roughness and it varied linearly with the inverse of Reynolds number. In this case, the friction factor of the Fanning equation can be calculated using the Hagen-Poiseuille equation (see Poiseuille Flow ).