Brayton Cycle Efficiency 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-clean

Evidence ID

t4-024

Effect

Computation or source lookup only

Input and validation requirements

• Division by zero occurs for back-work ratio when turbine work is zero, including the rp=1 boundary case.
• The exponent requires γ>1; γ=1 causes a degenerate zero-efficiency result, and γ≤1 is not a valid ordinary ideal-gas Brayton-cycle input.
• rp must be positive; rp=0 is invalid and negative pressure ratios are nonphysical.
• Regenerator effectiveness should be constrained to 0≤ε≤1.
• The regenerator formula requires a specified operating condition such as T4>T2; applying regeneration when T4≤T2 can produce nonphysical heat flow or misleading efficiency.
• If T3≤T2, the heat-addition denominator is zero or negative and efficiency is undefined or nonphysical.
• Celsius inputs used directly instead of kelvin produce incorrect temperatures and work values.
• Cp must be supplied or given a clearly documented default; changing Cp changes specific work but not the ideal simple-cycle efficiency.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

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

{
  "inputs": {
    "rp": 4,
    "gamma": 1.4,
    "T1_K": 288,
    "T3_K": 1400,
    "Cp_kJ_per_kgK": 1.005,
    "regeneration": false
  },
  "expected_outputs": {
    "eta": 0.32705,
    "specific_work_kJ_per_kg": 319.497,
    "back_work_ratio": 0.30569
  },
  "working": "a=(γ−1)/γ=0.4/1.4=2/7. F=rp^a=4^(2/7)=1.485994. T2=T1·F=288·1.485994=427.966 K. T4=T3/F=1400/1.485994=942.130 K. wc=Cp(T2−T1)=1.005·(427.966−288)=1.005·139.966=140.666 kJ/kg. wt=Cp(T3−T4)=1.005·(1400−942.130)=1.005·457.870=460.163 kJ/kg. wnet=wt−wc=460.163−140.666=319.497 kJ/kg. η=1−1/F=1−1/1.485994=0.32705. Back-work ratio=wc/wt=140.666/460.163=0.30569."
}

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