Understanding Corrosion in Water Pipelines: A Guide for Pipeline Designers


Pressure Drop

Last updated: October 10, 2018

What Does Pressure Drop Mean?

A pressure drop is the pressure difference that exists between points in a liquid-carrying network. This occurs when flow resistance resulting in frictional forces acts on the fluid while it is flowing through a tube.

The major identifiers of the resistance include fluid viscosity and fluid velocity in the pipe. Pressure drop elevates the same way as shear forces inside the piping network.


Corrosionpedia Explains Pressure Drop

A piping network contains a high level of roughness similar to many pipe joints, fittings, divergence, tube convergence and other properties. High viscosity and velocity lead to a bigger drop in pressure across the pipe section, while low velocity leads to little or no drop in pressure.

Pressure drop should be taken seriously as cavitation takes place when the operational pressure of the fluid falls below the vapor pressure. This causes bubbles and gas pockets, which eventually leads to collapse. This takes place in a very dramatic and explosive manner. In fact, this can generate steam in the piping network in as short as minutes.

This kind of corrosion can destroy impellers and volutes of pumps as well as valves. It can also contribute to other types of erosion corrosion. It can be prevented by decreasing the gradients of hydrodynamic pressure in order to prevent pressure drop under the air and liquid’s vapor pressure.

Other means to prevent corrosion in such cases include the use of cathodic protection as well as the application of resilient coatings.


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