Mixing Reynolds Number: Use the Impeller Length Scale

Define the Process Model

For a Newtonian stirred-fluid comparison, Re_m = ρND²/μ with N in revolutions per second. COMSOL’s mixer model distinguishes this basis and explains why its Newtonian viscosity expression cannot simply represent a shear-thinning field. Specify which Reynolds-number convention accompanies the chosen power or flow correlation.

Compare a Hypothetical Case

Assume an invented fluid has ρ = 1,000 kg/m³ and μ = 0.10 Pa·s. An impeller with D = 0.10 m at N = 5/s gives Re_m = 500. Increasing D to 0.20 m at the same speed gives 2,000. Diameter enters squared in this definition. Applying circular-pipe transition labels directly to these values would introduce an unsupported model assumption.

Complete the Engineering Review

Record the diameter, rotational rate and fluid properties used by the impeller correlation. For non-Newtonian material, request a justified effective-viscosity or rheological treatment rather than selecting a convenient single number. Check the correlation’s geometry and validity range. A regime descriptor is not a standalone prediction of blending time or product uniformity.

Use the manufacturing-vessel page with the actual agitator and product information. The example supplies no HM operating regime or power number. Pipe Reynolds number may still be useful for a connected line, but that is a different physical passage and correlation.

Which regime basis applies to an impeller rather than a transfer pipe?

This blank worksheet is for your own project. It contains no H M machine trial result.

Customer Questions

Related Equipment References

Review the actual offered equipment and application separately from this educational example.

• manufacturing-vessel page

Primary References

These references support the technical principles discussed in this guide. The worked examples and review questions are educational.

• COMSOL’s mixer model
• manufacturing-vessel page