AERO / PAIR 2 CONTINUATION - 2026-09-19
Pair 2 thermal-settling continuation
Alex Blythe - unchanged positive and clean-repeat branches from the retained 100 s state.
FINAL DISPOSITION
SLOW_THERMAL_SETTLING_SUPPORTED
TWO_FLUID_CHT_POSITIVE_TRUTH = ESTABLISHED for this Pair 2 fixture under its predeclared truth contract. This does not qualify HX-CFD or freeze the CHT profile.
Why this continuation ran
The 100 s positive state matched the analytical screen and closed its energy balance, but its outlet and solid-temperature histories were still moving. Retained-history slopes were used to freeze a bounded continuation before execution: T1 = 160 s and T2 = 240 s, with 20 s checkpoints. No T3 was permitted.
Pair 1 was excluded. The retained 4 s negative endpoint was not rerun, changed, or relabeled.
Frozen T2 evidence
| Check | Positive | Repeat |
|---|---|---|
| Solver completion | PASS | PASS |
| Shell outlet range, 200-240 s | 0.104 K | 0.104 K |
| Tube outlet range, 200-240 s | 0.249 K | 0.249 K |
| Solid mean-temperature range | 0.362 K | 0.362 K |
| Hot/cold duty mismatch | 0.332% PASS | 0.332% PASS |
| Total energy closure | 0.418% PASS | 0.418% PASS |
| Interface consistency | PASS | PASS |
| Direct outer-update tail | 0.00209 PASS | 0.00209 PASS |
| Analytical outlet/duty agreement | PASS | PASS |
| Positive repeatability | Exact trajectory and telemetry match | |
T2 endpoint: hot outlet 626.768 K, cold outlet 302.961 K, hot duty 7,654.6 W, cold duty 7,680.1 W, solid storage rate +6.56 W, and full signed closure 32.07 W.
Interpretation
T1 still failed the frozen stability window, while T2 passed it. The retained-to-continuation drift magnitude decreased across the declared windows, and the repeat stayed identical. The evidence supports slow thermal settling rather than a persistent unresolved thermal state for Pair 2.
The retained negative remains independently unsettled and its final fields remain in custody. Conservation, interface balance, and direct outer telemetry remain separate evidence layers; none was used as a substitute for thermal stationarity.
Qualification boundary
CHT_PROFILE = ARCHITECTURE_SUPPORTED_THRESHOLDS_NOT_ESTABLISHED. HX-CFD-QUAL-01 remains FAILED_NUMERICAL_GATES and withheld. HX-03 remains FROZEN_AND_BLOCKED. HX-04 Stage B remains blocked.