Pump Hydraulic Power Calculator

Inspectable records

Ledger state

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

Area

Thermodynamics, Fluids & Aero

Tranche

tranche-4

Evidence ID

t4-251

Ledger rows

1

No ledger note is attached.

Review findings

The two power formulas are correct under the stated SI-unit assumptions, but the specification needs explicit input units and validation constraints. The motor sizing output is undefined and should either be removed or given a documented formula and selection policy. An honest label should distinguish ideal hydraulic power, calculated pump shaft power, and actual motor electrical input.

Formula and scope findings

• The hydraulic-power formula Phyd=ρgQH is standard when ρ is in kg/m³, g is in m/s², Q is in m³/s, and H is in m; it produces watts.
• The shaft-power formula Pshaft=Phyd/η is standard for pump efficiency expressed as a decimal fraction.
• The claimed motor sizing suggestion has no defined formula, motor-sizing rule, service factor, rounding convention, or output unit, so it cannot be verified or honestly generated from this specification.
• The flow-rate input unit is unspecified; using L/min, L/s, or m³/h directly without conversion would produce incorrect results.

Unit assumptions

• g=9.81 m/s².
• Q must be converted to m³/s.
• H is total pump head in metres of fluid, not pressure in pascals or gauge pressure unless separately converted.
• ρ is fluid density in kg/m³.
• η is dimensionless pump efficiency represented as a decimal between 0 and 1, not a percentage.
• Phyd and Pshaft are returned in watts; kilowatts require division by 1000.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

An efficiency input of η = 0 causes an undefined shaft-power result, and η = 1.2 is physically invalid despite producing a raw numeric result. Negative flow also produces opposite-signed power unless the convention is explicitly defined.

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": {
    "Q_m3_s": 0.02,
    "H_m": 30,
    "rho_kg_m3": 998,
    "eta": 0.8
  },
  "expected_outputs": {
    "hydraulic_power_W": 5874.228,
    "shaft_power_W": 7342.785
  },
  "working": "Phyd=ρgQH=998×9.81×0.020×30. First, 9.81×0.020=0.1962. Then 0.1962×30=5.886. Then 5.886×998=5874.228 W. Pshaft=5874.228÷0.80=7342.785 W."
}

Related workflows

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-tranche4/tranche4-results.json
• BOUNDARY_HAZARD_CATALOG.json