Aerostatic thrust bearing, simple orifice restrictor with slot-flow check — fixed reference geometry (B)
Reference-geometry calculator (Ø40mm outer diameter, 5µm film, β=0.6 — fixed) for an aerostatic thrust bearing with a simple orifice restrictor, including a supply-slot vs. choked-flow area check (A3/A3c).
Load capacity, F91 N
Load coefficient, F̄0.181
Stiffness, S33.3 N/µm
Mass flow, ṁ0.992 mg/s
Volume flow, Q0.05 l/min
Orifice diameter, d0.083 µm
Feed slot area / orifice area, A₃/A11.5
Feed slot area / choked-flow area, A₃/A₃c6.8
Recess pressure ratio, pᵣ/pₛ0.68
The legacy "please login" demo lock froze D0/H0/B1. The formula also hardcodes the outer radius directly in the mass-flow/load terms, so this is kept as a fixed-geometry reference calculator rather than generalized. Only the inputs that were already free under the lock are exposed.
Method & references
- Aerostatic thrust bearing, simple orifice restrictor with a supply-slot choked-flow sanity check.
- FIXED GEOMETRY: outer diameter 40 mm, film 5 µm, β=0.6 — same rationale as c12_4a.
- Generalizing the outer radius is a real model change and is not done here — see docs/locked-calculators-review.md.
The computation is a literal port of the original client-side JavaScript from /calculators/c12_4b.htm. Results are verified equal to the original by an automated golden-master test. No formula has been re-derived or “improved”.