Question

Impeller :

1) Small radial impeller

2) medium radial impeller

3) Large radial impeller

4) Axial impeller

5) Turbine propeller

Which type of impeller can be used for fluids of high viscosity ?

Answer 1

Axial impellers are used for low-viscosity fluids as it is easier to create axial motion for low-viscosity fluids than the ones with higher viscosity, Turbine propellers cannot produce enough thrust to make fluids with high viscosity flow or mix, hence they are also used for low-viscosity fluids.

Radial impellers are preferable than axial impellers or turbine propellers for fluids with high viscosity because they make the fluids move perpendicular to the blades creating a radial motion which is easier to be created as compared to the axial motion for high viscosity fluids.

Also, it is recommended to use the radial impeller that covers the entire area from the axis to the walls so that highly viscous fluid does not become stagnant at the walls.

Hence, radial impellers with large blades are recommended to be used for fluids with high viscosity. Thus, the correct answer is 3) Large radial impeller.