Property/reference verification
NIST / Leachman hydrogen properties
Selected normal-hydrogen saturation and enthalpy states are checked against the Leachman et al. reference formulation and Table 14 data used by NIST/REFPROP.
Evidence type
Tier A property/reference verification. This confirms implementation consistency with an authoritative thermophysical reference; it is not a separate experimental validation campaign.
Source
Leachman, J. W.; Jacobsen, R. T.; Penoncello, S. G.; Lemmon, E. W. (2009), “Fundamental Equations of State for Parahydrogen, Normal Hydrogen, and Orthohydrogen,” Journal of Physical and Chemical Reference Data 38, 721–748.
Reference points and generated results
| Check | Input | Reference | OffshoreLH2 result | Relative error | Tolerance | Status |
|---|---|---|---|---|---|---|
| Saturation pressure | T = 20 K | 90.717 kPa | 90.7248 kPa | 0.00861% | 0.03% | PASS |
| Saturated liquid density | T = 20 K | 71.265 kg/m³ | 71.265 kg/m³ | 0% | 1×10⁻¹⁰ relative | PASS |
| Saturated vapour density | T = 20 K | 1.2059 kg/m³ | 1.2059 kg/m³ | 0% | 1×10⁻¹⁰ relative | PASS |
| Vapour specific enthalpy | T = 20 K, ρ = 1.2059 kg/m³ | 446.64 kJ/kg | 446.6413 kJ/kg | 0.000294% | 0.002% | PASS |
Interpretation. The saturated density values are taken directly from the Leachman saturation table in the implementation, so their exact agreement is a table-lookup verification, not an independent prediction. The pressure and enthalpy checks exercise the implemented equations against the reference state.
Reproducibility
The release gate is implemented in scripts/run_high_fidelity_release_validation.py and the normal-hydrogen formulation in src/hydrogen_thermophysics.cpp.