neqsim-cfd-coupling

CFD Coupling

A one-dimensional model works in bulk quantities. Damage does not: it concentrates wherever the local flow field departs from the bulk — bends, welds, restrictions, headers, tube bundles. Screening models bridge that gap with generic textbook multipliers.

This skill closes the gap properly. It takes whatever is known about a component (P&ID, tag register, datasheets, plant data), takes the fluid from a NeqSim flash, builds and runs an OpenFOAM case on the real geometry, and converts the solved field back into the factor the one-dimensional model was guessing at. When a CFD study already exists it qualifies that study instead of running a new one.

Every layer works on its own. NeqSim and OpenFOAM are both optional: without NeqSim the fluid state is stated directly, and without OpenFOAM the case is still written and can be transferred and run elsewhere.

When to Use

• A screening model needs a local enhancement factor and a generic multiplier is currently being assumed.
• Pressure drop, velocity or wall shear is needed on real geometry rather than on an equivalent-length correlation.
• Flow maldistribution across a bundle, manifold or header matters to the answer.
• Two phases share the line and the interface matters - stratified, slug or annular flow, a free surface, or liquid accumulating in a low point.
• A CFD report, vendor flow analysis or CFD/FEM deliverable is attached to an equipment tag and must be qualified before its numbers are used.
• A new CFD run must be specified and needs fluid properties, turbulence inlet values and near-wall mesh sizing.
• A tonal noise or vibration observation needs a fail-closed readiness decision before transient compressible CFD, acoustics, or structural coupling is scoped.

When Not to Use

• As a substitute for a qualified CFD engineer on a design decision. This is a screening and coupling toolkit, not a verification-and-validation review.
• To extract a number from a CFD study that fails the quality gate.
• For droplet break-up statistics, separation efficiency or a dense dispersed phase. The multiphase screening will say lagrangian or euler_euler; those cases are recommended with a reason but not generated here.
• For a temperature field. The generated cases solve momentum only, with the fluid properties frozen at the inlet flash. A stagnant or dead-leg region, a buoyancy-driven or thermally stratified region, or any wall-temperature question needs a buoyant conjugate solver (buoyantSimpleFoam, buoyantPimpleFoam, chtMultiRegionFoam) that this skill does not write. Use fem-coupling for the wall and near-wall temperature, and hand-build the buoyant case if the fluid-side field itself is the deliverable.
• To diagnose a tonal aeroacoustic source with the generated steady RANS or incompressible VOF cases. Call assess_aeroacoustic_readiness first. A ready case still requires a separately configured transient compressible LES/DES, spectral pressure probes, acoustic propagation, and structural modal analysis when vibration is in scope.