User-entered Darcy factor
Major pipe pressure loss
Inputs
User-entered Darcy (not Fanning) friction factor for the stated condition.
Straight developed-flow length for the major-loss screen.
Internal or hydraulic diameter of the displayed conduit.
User-entered density at the stated fluid condition.
User-entered mean cross-section velocity.
Results
Major friction pressure lossΔp
16.2
Head loss in flowing fluidhL
1.6519
Dynamic pressureq
1,620
Δp = f(L/D)(ρv²/2); hL = Δp/(ρg)
A first-pass number, not a code check, certification, or approval. Read the method and its limits below. What this is and is not.
Method
Formula, when it applies, and when it does not
Calculate major friction pressure and head loss from a Darcy friction factor, geometry, density, and mean velocity.
Δp = f(L/D)(ρv²/2); hL = Δp/(ρg)
When
- Fully developed steady flow
- Incompressible fluid
- Major loss only
Don’t
- This is Darcy–Weisbach major loss with a user-entered Darcy factor. It excludes fittings and minor losses, elevation, pumps, compressibility, entrance/development effects, non-Newtonian behavior, transient flow, pressure rating, and any pipe-size decision.
White, Fluid Mechanics