Mechanical seal bearing capacity — tapered film

Load capacity, flow rate and axial stiffness for a mechanical seal with a tapered (converging) film, treated as an annular hydrostatic collar bearing.

✓ validated against legacyoriginal: /engineering-abc/calculators/c11_1.htm

Outer diameter, 2R₀mmInner diameter, 2R₁mmFilm thickness, h₀µmFilm thickness, h₁µmSupply pressure, p_S10⁶ PaAmbient pressure, p_A10⁶ PaViscosity, ηPa·s

Load capacity, F'=F/(A(pS-pA))0.75

Flow rate, Q'10.6

Stiffness, S'0.167

Load capacity, F135.7 N

Flow rate, Q25.4 10⁻⁶ l/min

Inherent stiffness, S=-dF/dh30.2 10⁶ N/m

Method & references

The dimensionless load F' is the pressure-gradient factor k₁ in mechanical-seal technology: the ratio of the integrated pressure distribution F to the hydrostatic pressure (pS-pA) acting on the seal surface A.
With a parallel film, k₁=0.5 and S=0. A tapered film develops axial bearing stiffness.

The computation is a literal port of the original client-side JavaScript from /engineering-abc/calculators/c11_1.htm. Results are verified equal to the original by an automated golden-master test. No formula has been re-derived or “improved”.

Mechanical seal bearing capacity — tapered film — Engineering ABC