Pipe Flow Expert Example Systems 11

Common 05 - Enlargements & Contractions

Figure 5 Common 05 - Enlargements & Contractions

When two pipes of different diameters are joined there will be some pressure loss across the junction, due to the change in fluid velocity.

The Pipe Flow Expert database includes K factor calculators for:

1. Sudden enlargements, where a smaller pipe feeds into a larger pipe.

2. Sudden contractions, where a larger pipe feeds into a smaller pipe.

3. Gradual enlargements, where a smaller pipe expands gradually to the larger pipe size.

4. Gradual contractions, where a larger pipe contracts gradually to the smaller pipe size.

The contraction/enlargement fitting 'K' factor calculation is based on the internal diameters of the pipes to be connected and requires the resulting 'K' factor to be used with the fluid velocity in the ENTERING pipe.

Examples are shown for:

1. Sudden Enlargement (fitting on smaller pipe).

2. Sudden Contraction (fitting on larger pipe).

3. Gradual Enlargement (fitting on smaller pipe).

4. Gradual Contraction (fitting on larger pipe).

The Pipe Flow Expert fittings database also includes calculators for Rounded Pipe Entrances (from tanks) and Long Pipe Bends.

Note: In this example, pipe entrance fittings have been purposely omitted to allow focus on the modelling of contraction and expansion fittings.