{
  "evidence": "DESIGN_TO_BUILD_NOT_A_BUILT_RIG",
  "physical_measurements": 0,
  "purpose": "Measure whether cooling increases mass flow through the same installed core at the same total-pressure head, and measure the full source/cold budget.",
  "primary_geometry": {
    "gap_m": 0.001,
    "fin_m": 0.0002,
    "width_m": 0.023,
    "height_m": 0.019,
    "wall_m": 0.0005,
    "length_m": 0.05,
    "cores": 2,
    "slots_each": 19
  },
  "target_head_Pa": 60.20591581873078,
  "head_control_target_Pa": 0.1,
  "inlet_temperature_K": 293.15,
  "cold_wall_target_K": 273.15,
  "dry_air_dewpoint_max_K": 268.15,
  "inlet_flow_relative_standard_uncertainty_target": 0.002,
  "minimum_paired_blocks": 6,
  "core_wall_temperature_measurement_required": true,
  "source": "Pressure-fed duct article. A blower/plenum holds inlet total pressure; outlet is ambient. This is not a 0.2 m wide wind tunnel containing a 0.2 m wide car.",
  "blower_design_envelope": {
    "flow_m3s": 0.02,
    "pressure_Pa": 1000.0,
    "fluid_power_W": 20.0,
    "electrical_input_screen_at_assumed_50pct_efficiency_W": 40.0,
    "note": "A low-pressure metered test envelope, not a selected fan. Regulated bleed/bypass permits stable 60 Pa at lower core flow."
  },
  "pressure_plenum_internal_m": [
    0.1,
    0.24,
    0.1
  ],
  "reservoir": {
    "vented_volume_L": 3.0,
    "initial_ice_kg": 1.0,
    "initial_water_kg": 0.5,
    "ideal_hold_time_s_at_selected_heat": 5183.668068221076,
    "note": "Actual hold time includes ambient heat leak, pump heat and lines. This is ice-water, not a nitrogen reservoir."
  },
  "predictions": {
    "same_warm_core_mass_kgs": 0.003609794495901622,
    "cold_core_mass_kgs_fine": 0.003791092044299381,
    "coarse_matched_core_gain_fraction": 0.050058819854936765,
    "cold_heat_W_fine": 64.34632688864802,
    "open_bypass_mass_kgs_same_head": 0.015968007520434837,
    "evidence": "NUMERICAL_PREDICTIONS_ONLY"
  },
  "material_direction": [
    "New precision-machined aluminium for the split duct and selector housing; bore roughness and seams measured after manufacture.",
    "New oxygen-free copper for the replaceable fin/core coupon; actual conductivity and joint quality must be documented.",
    "Appropriate documented low-temperature seals for the ice-water test, with leak calibration.",
    "Independent commercial pressure, flow, dewpoint, temperature and electrical instruments; no inferred flow from uncalibrated rotor speed."
  ],
  "instrumentation": [
    "Mass flow upstream in the warm line, with independent reference calibration; record calibration uncertainty and instrument identity.",
    "Differential inlet-total-to-outlet-static pressure at the same physical taps for warm and cold tests.",
    "Inlet, outlet, core-wall and bath temperatures, inlet dewpoint and ambient pressure.",
    "DC voltage/current for blower, recirculation pump, valves and controls; meter the whole bench supply.",
    "Bath melt mass and an otherwise identical zero-flow heat-leak/pump blank.",
    "Optional independent two-axis force balance with mechanically isolated hoses and cables; force is not inferred from a render."
  ],
  "test_sequence": [
    "Inspect bore dimensions and clearances; perform a warm leak/head sweep before cooling.",
    "Measure warm core and warm bypass controls at matched head.",
    "Randomise at least six paired warm/cold blocks using the same core, plumbing, taps and calibrated instruments.",
    "Accept a run only after head, inlet conditions, core wall and mass flow are stable; log the complete trace rather than a chosen peak.",
    "Repeat with zero temperature difference; the treatment effect should disappear.",
    "Analyse paired log flow ratios with uncertainty and control mismatch. Report absolute flow versus the bypass alongside the matched-core effect.",
    "Use calorimetry to compare air cooling with bath depletion and total electrical input. Repeat independently before making a performance claim."
  ],
  "acceptance": [
    "A positive lower 95% paired flow-difference bound after systematic uncertainty and matched-head checks.",
    "No accepted run above the protocol dewpoint or with unexplained leakage, sensor drift, thermal mass transient or pressure-control mismatch.",
    "A measured increase relative to the warm core is a cold-flow mechanism result, not a vehicle thrust, top-speed or net-energy result."
  ],
  "next_hardware": [
    "Build the single upper-vent/rear-selector CAD module and test cover movement under low pressure.",
    "Demonstrate rear spring return and a jammed-upper-cover fallback before using the routing logic with a powered rotor.",
    "Measure pressure loss versus mass flow, valve angle, rotor load and core temperature. Replace the assumed maps with those measurements."
  ]
}