1. Introduction

2. Calculation

3. Pipe velocities recommendation

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.

With :

Q = Volumetric flowrate (m^{3}/s)

D = Pipe diameter (m)

u = Fluid velocity in pipe (m/s)

K coefficient can reasonably be used until Re=500, below, specific coefficients should be used.

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

[1] Mecanique et Rheologies des fluides en Genie
Chimique, Midoux, Tec et Docs, 1993

[2] Rules of Thumbs for Chemical Engineers, Brannan,
Gulf, 2005