HomeCalculatorsPurifier Stokes Settling Velocity

Purifier Stokes Settling Velocity

Settling velocity of a dispersed-water droplet in oil: v = d²·(ρ_w − ρ_o)·g / (18·μ). The basis of centrifugal purifier sizing.

LubricationPurifier
Settling velocity
0.000000m/s
Settling velocity
1.6mm/h
Formula, assumptions, and limits

Stokes' law - for small droplets (Re < 1). Centrifugal purifier increases g-equivalent to ~5000–10000 × gravity, speeding up separation by the same factor. Sigma equivalent area Σ relates settling time in a tube to purifier bowl size.

Symbol legend

SymbolMeaningUnitSource
Droplet diameterminput µm/10^6
Water and oil densitieskg/m³fluid property
Oil dynamic viscosityPa·sASTM D445 at T