Source: https://guthlabs.ai/docs/instruments/fluid-property-lookup-water-air-common-fluids/

instrument / verified-clean

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

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/fluid-property-lookup-water-air-common-fluids/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/fluid-property-lookup-water-air-common-fluids/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/fluid-property-lookup-water-air-common-fluids/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/fluid-property-lookup-water-air-common-fluids/qualification/>)

## Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

**Area**: Thermodynamics, Fluids & Aero

**Tranche**: tranche-7

**Evidence ID**: t7-115

**Ledger rows**: 1

No ledger note is attached.

## Review findings

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.

### Formula and scope findings

- 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.

### Unit assumptions

- 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.

## Boundary hardening

**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.

## Errata and corrections

No applied erratum is attached to this unique-name record.

## Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

````
{
  "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."
}
````

## Related workflows

No source-defined multi-instrument workflow membership is recorded.

## Sources and evidence

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

- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`

- `evidence-tranche7/tranche7-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`