The density is an important fluid property that depends on the temperature. The density of the pumped medium has a direct influence on the power requirement of the pump.

The mechanical power requirement of a centrifugal pump (shaft power) is directly proportional to the density of the pumped medium.
P 2 ~ ρ

P 2 = shaft power
ρ = density of the pumped medium

In contrast, the throttle curve of the pump H (Q) and the efficiency η (Q) are independent of the density.

These relationships are automatically taken into account by the pump selection software.

More articles on this topic

Newtonian Fluid

A fluid is classified as being Newtonian if it conforms to NEWTON’s friction law, i.e. if viscosity remains constant with agitation or varying shear rate and its shear rate being proportional to the velocity gradient vertical to the direction of flow. That means, that the viscosity is only affected by temperature changes.

Read more