The fluid velocity in a pipe is a fundamental data to calculate to be able to characterize the flow in a pipe, thanks to the Reynolds number, and size a pipe circuit calculating the pressure drop expected for a certain flow. When designing the pipe, it is necessary to chose a fluid velocity to have good compromise in between pressure drop and economics, some recommendations are given below.
| Fluid | Recommended velocity |
|---|---|
| Water | 1.5-2.5 m/s [1] 1-2.5 m/s [2] |
| Air | 10-30 m/s [1] 30 m/s [2] |
| Steam | 20-40 m/s [1] HP : 45 m/s [2] LP : 30 m/s [2] |
| Gas Process flows | 15-45 m/s |
| Dry gas | 30 m/s [2] |
| Wet gas | 18 m/s [2] |
These values are given as an indication for pre-sizing. Each company should have its own guideline to be followed.
In addition to the sources given below, one may also wish to consult Applied Process Design for Chemicals and Petrochemicals plants, Ludwig, Gulf, page 85 which is giving values for specific applications like sodium hydroxide, ethylene, vinyl chloride.
[1] Mecanique et Rheologies des fluides en Genie Chimique, Midoux, Tec et Docs, 1993 [2] Rules of Thumbs for Chemical Engineers, Brannan, Gulf, 2005The content of PowderProcess.net is copyrighted but no warranty nor liability is ensured. The content of this site is to be seen as a help and important information and calculation must always be double checked by the user through the quality procedure of his organization or by checking another source. The user must always respect all applicable regulation. The use of the information is at the user and its organization own risk and own cost.
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