Curve Corrections for Different Fluids

Pump curves are mostly established for water.

Duty (H-Q) and efficiency (h-Q) curves become close to being valid for all Newtonian fluids. In practice this will however become not applicable for fluids of kinematic viscosities above 20mm²/s ( 20 cst ) due to the influence of a higher Reynolds Number with increasing viscosity. Empirical conversion methods have been developed for curve corrections for medium- and high-viscous fluids, which in practice require extensive interpretations of complicated diagrams.

Adavance pump selection programs (e.g. Spaix) contain a curve correction method whose development is mainly based on methods proposed by the Hydraulic Institute / USA).

The Best Efficiency Point of the pump is of vital importance with all the known curve correction methods.



The following conditions can be stated for the validity of this method:

 

• Fluid displacement by means of a centrifugal pump under normal operating conditions
• Handling of Newtonian Fluids