Radiation Heat Transfer Calculator implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-with-binding-errata

Evidence ID

t4-144

Effect

Computation or source lookup only

Input and validation requirements

• Division by zero or nonphysical results occur if ε1 or ε2 is zero in the two-surface denominator.
• The denominator formula becomes invalid when the surfaces do not have equal area and mutual view factor one.
• Missing view-factor usage can cause large errors for partial visibility, separated surfaces, or enclosure geometries.
• Negative, zero, or non-absolute temperatures are invalid for this radiation formula; temperatures must be positive kelvin.
• Emissivities outside the interval 0 to 1 are nonphysical.
• The result can be negative when T1<T2; the interface must clearly label this as heat transfer from surface 2 toward surface 1.
• An emissivity table needs material, wavelength, temperature, and surface-condition assumptions; tabulated emissivity is not universally a single constant.
• The honest label is incomplete because it does not explicitly state the equal-area, F=1, diffuse-gray, opaque, isothermal assumptions behind the two-surface formula.

Required corrections

[
  {
    "vector": 1,
    "field": "q_net_W",
    "wrong": 616.9367,
    "correct": 6169.395,
    "cause": "exactly 10x low; her v2/v4 verify with same sigma"
  }
]

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "formula": "q=εσA(T1^4−T2^4)",
    "epsilon": 1,
    "area_m2": 2,
    "T1_K": 500,
    "T2_K": 300,
    "view_factor": 1
  },
  "expected_outputs": {
    "q_net_W": 616.9367368
  },
  "working": "T1^4=500^4=62,500,000,000 K^4. T2^4=300^4=8,100,000,000 K^4. Difference=54,400,000,000 K^4. q=1×(5.670374419×10^-8)×2×54,400,000,000. q=616.9367368 W."
}

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-tranche4/tranche4-results.json
• tranche errata record