Description
To calculate the pressure loss in a pipe it is necessary to compute a pressure drop, usually in fluid head, for each of the items that cause a change in pressure. However to calculate the friction loss in a pipe for example, it is necessary to calculate the friction factor to use in the Darcy-Weisbach equation which determines the overall friction loss.
The friction factor itself is dependent on internal pipe diameter, the internal pipe roughness and the Reynold's number which is in turn calculated from the fluid viscosity, fluid density, fluid velocity and the internal pipe diameter.
There are therefore a number of sub-calculations that must take place to calculate the overall friction loss. Working backwards we must know the fluid density and viscosity properties, know the pipe diameter and roughness properties, calculate the Reynold's number, use this to calculate the friction factor using the Colebrook-White equation, and finally plug in the friction factor to the Darcy-Weisbach equation to calculate the friction loss in the pipe.
After calculating the pipe friction loss we then need to consider possible fitting losses, change in elevation and any pump head added. Summing these losses/gains will give us the overall pressure drop in the pipe. The following sections consider each calculation in turn.
In these post we will provide Excel Calculator to Calculate the Head Loss in a Pipe With Fittings.
- Calculation will allow you to estimate the head loss (pressure drop) in a pipe with a nice clean internal surface. In general head loss is higher in small diameter pipes and long lengths of pipe. Diameter is the greater of the 2 impacts.
- Type in your variables and look for the answer below. There are two sections. In this first section you can easily convince your self of importance of pipe diameter. Just type in diffferent sizes for same flow rate and same pipe length.
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