NeqSim computes separator carry-over through a small Service Provider Interface (SPI), so a proprietary correlation can be supplied as a separate JAR without any of its content entering the public repository.

Models that ship with NeqSim

Id What it does
zero Reports no carry-over. Useful as a deliberate baseline.
spe-0.1gal-mmscf Default. A fixed 13.4 L of liquid per MSm³ of gas — the SI equivalent of the 0.1 US gal/MMscf rule of thumb from The Savvy Separator: A Century of Carry-Over — 0.1 gal/MMscf (SPE / JPT). Split between oil and water at the feed water cut.
neqsim-7stage The open-source 7-stage physics chain, evaluated through SeparatorPerformanceCalculator.

Select one on a separator:

separator.setEntrainmentProvider("neqsim-7stage");
EntrainmentResult result = separator.getEntrainmentResult();
double oilCarryOver = result.getOilInGasKgPerHr();

With nothing selected the default applies. Selection affects getEntrainmentResult() only — it does not change the entrainment applied during run(), so adding it to an existing model cannot move that model’s results.

The default is an assumption, not a prediction

spe-0.1gal-mmscf returns the same litres per MSm³ whatever the separator is doing. It does not respond to gas load factor, mesh pad selection or overload, so a vessel running at twice its capacity still reports 13.4 L/MSm³. That is the point of a rule-of-thumb default, but it has one consequence worth stating in any report: a capacity constraint fed from this model can never trip on carry-over. Use neqsim-7stage, or a calibrated private model, when the number has to respond to the design.

Supplying a private model

Implement EnhancedEntrainmentProvider in your own project, depending on public NeqSim only:

public class MyCorrelationProvider implements EnhancedEntrainmentProvider {
  public String getId() {
    return "my-correlation-v1";
  }

  public String getVersion() {
    return "1.0.0";
  }

  public EntrainmentApplicability checkApplicability(Separator separator) {
    // report every input outside your validity envelope
    return EntrainmentApplicability.ok();
  }

  public EntrainmentResult compute(Separator separator) {
    // your correlation here
    return new EntrainmentResult(getId(), getVersion(), oilKgPerHr, waterKgPerHr, gasKgPerHr, band);
  }
}

Register it by adding one line to your JAR:

META-INF/services/neqsim.process.equipment.separator.entrainment.EnhancedEntrainmentProvider

containing the fully-qualified class name. When that JAR is on the classpath, ServiceLoader finds it and setEntrainmentProvider("my-correlation-v1") works. When it is absent, the call fails with a message naming the models that are available, rather than silently substituting a different correlation.

What stays public and what stays private

The public repository holds the maximum structure that leaks nothing: the interface, the result and applicability types, the registry, and provider ids. The id eqn-pi-v1 is public; the correlation behind it is not. Model parameters, validity envelopes, vendor-tagged data and the tests that check the correlation reproduces its reference cases live in the private repository.

A maintainer reading public NeqSim can therefore see what a provider must accept and return without being able to reconstruct how it computes.

Stability contract

Implementer checklist