The factor of proportionality in the previous equations is called theĀ Moody friction factor and is determined from the Moody resistance diagram shown in Figure 8-1. The friction factor is sometimes expressed in terms of the Fanning friction factor, which is one-fourth of the Moody friction factor. In some references the Moody friction factor is …

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## Darcy’s Equation

This equation, which is also sometimes called the Weisbach equation or the Darcy-Weisbach equation, states that the friction head loss between two points in a completely filled, circular cross section pipe is proportional to the velocity head and the length of pipe and inversely proportional to the pipe diameter. This can be written: Equations 8-5 …

Read More…## Bernoulli’s Theorem

It is customary to express the energy contained in a fluid in terms of the potential energy contained in an equivalent height or “head” of a column of the fluid. Using this convention, Bernoulli’s theorem breaks down the total energy at a point in terms of 1. The head due to its elevation above an …

Read More…## Flow Regimes

Flow regimes describe the nature of fluid flow. There are two basic flow regimes for flow of a single-phase fluid: laminar flow and turbulent flow. Laminar flow is characterized by little mixing of the flowing fluid and a parabolic velocity profile. Turbulent flow involves complete mixing of the fluid and a more uniform velocity profile. …

Read More…## Reynolds Number Piping

The Reynolds number is a dimensionless parameter that relates the ratio of inertial forces to viscous forces. It can be expressed by the following general equation: The Reynolds number can be expressed in more convenient terms. For liquids, the equation becomes:

Read More…## Pressure Drop In Piping

Piping design in production facilities involves the selection of a pipe diameter and a wall thickness that is capable of transporting fluid from one piece of process equipment to another, within the allowable pressure drop and pressure rating restraints imposed by the process. The first step in being able to make these changes is to …

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