A water-tested centrifugal pump curve may need a fluid-specific correction before it supports a viscous-liquid duty.
Identify the Physical Basis
Viscosity can change centrifugal-pump flow, head and efficiency, while also changing the piping loss. KSB’s viscosity reference describes empirical water-to-viscous-liquid curve corrections with defined application limits. A correction belongs to a particular pump, fluid and duty range. It is not a universal percentage to subtract whenever a product is described as thick.
Work Through an Example
Imagine an educational quotation comparison in which an engineer supplies illustrative factors C_Q = 0.90, C_H = 0.95 and C_η = 0.80 at an identified reference point. Water-reference values of 10 m³/h, 20 m and 60% efficiency become 9 m³/h, 19 m and 48% under that stated calculation. The invented factors demonstrate three separate corrections; they are not values for any HM product or a supplier’s published method.
Use the Result in the Review
Request the original water curve, selected correction method and applicability statement together. Provide viscosity and density at the product temperature, including the expected operating range. Recalculate the system curve too; shifting only the pump curve can miss a larger route-loss change. Review corrected power and suction requirements using the supplier’s complete assessment rather than assuming every quantity scales by the flow correction.
For a processing-tank transfer discussion, describe the actual liquid and connected route. A non-Newtonian formulation requires an appropriate rheological treatment. A single viscosity reading or a density conversion alone does not establish that a Newtonian correction chart applies.
Which correction or evidence connects the water-reference curve to the actual Newtonian liquid?
This blank worksheet is for your own project. It contains no H M machine trial result.
| Review field | Reference or result | Responsible person |
|---|---|---|
| Reference curve speed and diameter | To complete | To complete |
| Fluid viscosity, density and temperature | To complete | To complete |
| Correction method and validity limits | To complete | To complete |
| Corrected pump and system duty together | To complete | To complete |
Customer Questions
Can I reuse the same correction for every product?
No. Check the fluid properties, pump and method’s range.
Is motor power reduced when flow falls?
Not necessarily. Efficiency and other duty quantities also change.
Does an apparent viscosity establish Newtonian behaviour?
No. The shear-dependent behaviour needs separate characterization.
Related Equipment References
Review the actual offered equipment and application separately from this educational example.
Primary References
These references support the technical principles discussed in this guide. The worked examples and review questions are educational.
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