Water-lubricated journal bearing

PV-value, side-leakage flow, power loss and frictional temperature rise of a water-lubricated journal bearing operating at near-full eccentricity, assuming adiabatic conditions.

✓ validated against legacyoriginal: /calculators/waterlub.htm

Bearing load, FNCoefficient of friction, μShaft diameter, D10⁻³ mBearing length, L10⁻³ mDiametric clearance, ΔD10⁻³ mRotational speed, nrpmViscosity, ηPa·sDensity, ρ10³ kg/m³Specific heat capacity, c10³ J/(kg·K)Forced flowForced flow unitSide leakage output unit

Bearing length number, L/D1.21

PV-value0.4 MPa·m/s

Flow number, C_q0.725

Power loss, N = μF·2πn/601707.14 W

Side leakage, Q109.722

Frictional heating, ΔT13.4 K

Method & references

Water-lubricated bearings operate at near-full eccentricity (ε=0.999 assumed) because of water’s low viscosity.
Frictional heating assumes adiabatic boundary conditions: power loss N is drained by the natural side leakage Q (plus any forced flow) when submerged.
Flow through the bearing can be improved with axial grooves (forced flow via an applied pressure difference) — see the hydraulic diameter calculator.

The computation is a literal port of the original client-side JavaScript from /calculators/waterlub.htm. Results are verified equal to the original by an automated golden-master test. No formula has been re-derived or “improved”.

Water-lubricated journal bearing — Engineering ABC