Vacuum Engineering (vacuum-engineering)
Purpose
Screen vacuum chamber pump-down time, molecular-flow conductance, chamber force on windows/flanges, and gas throughput at target pressure. Supports preliminary vacuum system sizing for research and industrial hardware.
Physics & theory
Ideal gas pump-down follows exponential pressure decay: for chamber volume and effective pumping speed . Molecular-flow conductance of a circular tube (air, room temperature) approximates L/s with diameter and length in cm.
Pressure differential across area produces force — critical for viewport and door design. Throughput at target pressure sets required pump capacity for dynamic gas load (outgassing, leaks).
Advanced systems calculators use lumped-parameter screening models suitable for concept trade studies. Each calculator returns explicit assumptions and warnings arrays documenting model limits. Constants such as ( sigma ) (Stefan–Boltzmann), ( mu_0 ), and ( R ) (gas constant) use SI definitions from the solver source.
Results are not certified for regulatory submission without independent verification against detailed analysis or test data.
Governing equations
Numerical method
Closed-form ideal gas pump-down and molecular conductance (advanced-systems/calculators). Warnings issued when target pressure remains in viscous-dominated range (> 100 Pa typical transition context).
Inputs
| Parameter | Description |
|---|---|
volume | Chamber volume (m³) |
pumpSpeed | Effective pumping speed (m³/s) |
initialPressure, targetPressure | Pressure range (Pa) |
tubeDiameterMm, tubeLength | Vacuum line geometry |
pressureDiff, projectedArea | Force calculation |
Outputs
- Pump-down time, molecular conductance (L/s), chamber force (N), target throughput (Pa·m³/s), assumptions and warnings.
Design codes & checks
- Indicative: Pump-down, conductance, vacuum force screening
- ISO: ISO 21360 vacuum pump performance context
- ASTM: ASTM E595 outgassing context
Assumptions & limitations
- Isothermal ideal gas; constant effective pumping speed.
- No viscous–molecular transition modeling or outgassing transients.
- Conductance network not solved — single tube segment only.
- Leak rate testing procedures not included.
References
- O'Hanlon, J. F. A User's Guide to Vacuum Technology, 4th ed. Wiley.
- Roth, A. Vacuum Technology, 3rd ed. Elsevier.
- ISO 21360-1:2012. Vacuum pumps — Performance test methods.
- AVS. Recommended Practices for Vacuum Technology.
- PhyCalcPro verification benchmarks in
src/data/verification/where available for this module. - Beer, F. P., et al. Mechanics of Materials, 8th ed. McGraw-Hill — foundational stress and deformation theory.