AFT Application Topics
Viscosity Corrections for Centrifugal Pumps
When a pump curve is input into AFT Fathom or AFT Impulse, the pump performance is assumed to apply to the viscous fluid the same way it applies to water. However, when the system fluid is actually more viscous than water, the pump curve requires adjustments to account for the degraded performance of the pump due to increased losses. When the “Use Viscosity Correction” box is checked on the Optional tab of the Pump Properties window, AFT Fathom and AFT Impulse automatically calculate the viscosity correction factors (CQ, CH, and Cƞ) defined by the American National Standards Institute ANSI/HI 9.6.7-2010. These factors are then applied to the pump to determine the pump head and flow that will result with the viscous fluid.