Pipe Pressure-Drop Scenario Calculator

How the pipe pressure-drop scenario calculator works

Convert diameter to metres and flow to m³/s. Mean velocity is Q ÷ (πD²/4). Modeled pressure loss in Pa = (Darcy factor × length / diameter + sum of minor-loss K) × density × velocity² / 2. Divide by 1,000 for kPa. Hydraulic loss power is Q × pressure loss ÷ 1,000 in kW.

Supply a reviewed Darcy factor; this is not a roughness/Reynolds/Colebrook solver. A Fanning factor is four times smaller and cannot be substituted. Single-phase incompressible flow and applicable K values are assumed. Static elevation, compressible gas, surge, cavitation, pipe ratings and a safe pump/pipe design are outside the model.

Quantities use the stated units and finite bounded inputs. Whole purchases round up under the documented model; cost components round half-up to cents before totals are summed. Undefined ratios stay unavailable. π and logarithms use normal numeric precision. Display rounding does not alter the entered assumptions.

Worked example

At 10 L/s in a 100 mm pipe, velocity is about 1.273 m/s. For 100 m length, Darcy factor 0.02, K sum 2 and density 1,000 kg/m³, loss is 176/π² ≈ 17.833 kPa. Doubling flow to 20 L/s makes this ideal loss four times larger, about 71.331 kPa.

Sources and assumptions

The source material explains the underlying calculation or pricing structure. Entered prices, costs, schedules and scenario choices are your assumptions; this tool does not obtain supplier quotes or predict actual results.

• DOE Pumping System Performance sourcebook