Fluid Property Lookup (Water/Air/Common Fluids) mechanism

Model scope

Core derived-property formulas and lookup interpolation are standard, but the instrument needs an explicit table schema: fluid identity and composition, phase, pressure basis, temperature range, interpolation rule, source edition, and behavior at phase boundaries. Verdict is NEEDS_REVIEW because the current specification does not define those constraints or resolve the conflicting saturation/1 atm convention.

• Table interpolation is a valid method only between explicitly tabulated temperatures and under the same pressure/phase conditions; the interpolation rule is not specified, so linear interpolation must be declared as an assumption.
• Kinematic viscosity must be computed as ν = μ/ρ, and Prandtl number as Pr = μ cp/k; the specification does not explicitly state these derived formulas.
• Gas properties require a defined pressure model or pressure-specific tables. Temperature alone is insufficient for density, and pressure can also affect other properties.
• The supported fluid list, valid temperature ranges, phase boundaries, and saturation-versus-single-pressure conventions are unspecified.
• Near phase changes, properties can be discontinuous or strongly nonlinear, so unrestricted interpolation can produce invalid values.

Units and conventions

• Temperature inputs are in kelvin unless explicitly labeled in degrees Celsius; the vectors below label temperature units to remove ambiguity.
• Pressure is absolute pressure in pascals; 1 atm = 101325 Pa exactly for these vectors.
• Density ρ is in kg/m^3, dynamic viscosity μ is in Pa·s, kinematic viscosity ν is in m^2/s, thermal conductivity k is in W/(m·K), and specific heat cp is in J/(kg·K).
• Prandtl number is dimensionless and calculated as Pr = μ cp/k.
• The air entries are dry-air values at approximately 1 atm; the water entries are liquid-water values except the 100 °C entry, which is at saturation pressure.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "fluid": "water",
    "temperature": 20,
    "temperature_unit": "degC",
    "pressure": 101325,
    "pressure_unit": "Pa",
    "phase": "liquid"
  },
  "expected_outputs": {
    "rho_kg_m3": 998.2,
    "mu_Pa_s": 0.001002,
    "nu_m2_s": 0.00000100381,
    "k_W_mK": 0.598,
    "cp_J_kgK": 4182,
    "Pr": 7.0073
  },
  "reference_data": {
    "temperature_C": 20,
    "rho_kg_m3": 998.2,
    "mu_Pa_s": 0.001002,
    "k_W_mK": 0.598,
    "cp_J_kgK": 4182,
    "pressure_Pa": 101325,
    "source_convention": "Widely tabulated standard liquid-water property values; Incropera thermophysical-property tables, approximately 20 degC and 1 atm"
  },
  "working": "ν = μ/ρ = 0.001002 Pa·s / 998.2 kg/m^3 = 1.00381×10^-6 m^2/s. Pr = μ cp/k = (0.001002×4182)/0.598 = 4.190364/0.598 = 7.0073."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The specification does not define a pressure-validity rule, phase-selection rule, or absolute-versus-gauge pressure convention. Zero absolute pressure produces zero density and an undefined kinematic viscosity, while the saturation branch is non-unique at the phase switch unless phase or quality is supplied.

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche7/tranche7-results.json
• BOUNDARY_HAZARD_CATALOG.json