6. Pipe sizing

6.1 Notion of economic optimum

The choice of pipe diameter must be adapted to the conditions of the flow intended to pass through it.

In some cases, upper and/or lower limits to fluid velocity are imposed by physical conditions. This is generally the case if the flow is two-phase: for example, a sand-laden liquid [24] must not flow too slowly (minimum velocity of the order of 0.30 to 0.60 m / s) to avoid deposits; too fast a flow, on the other hand, risks causing rapid wear of the pipe (maximum velocity of the order of 4 to 5 m / s); similarly, liquid/gas flows must respect certain velocities if we wish to maintain an imposed flow configuration