Internal Flow & Pressure Drop
Every internal flow & pressure drop calculator on CalcEngines — each with its formula, a worked example, the standard it follows and the assumptions it makes.
5 calculators in this section
- Darcy-Forchheimer Porous Media Coefficients CalculatorTurn a measured pressure-drop curve into the viscous and inertial resistance coefficients your solver asks for: a closed-form least-squares fit of Δp/L = a·v + b·v² over up to five points, α, 1/α and C₂ in the units Fluent, OpenFOAM and Star-CCM+ want, the name of the box each goes in, and an honest statement of whether your data determined them at all. Plus the perforated-plate case from open-area ratio.
- Entrance Length CalculatorHow much straight inlet duct you need before the profile is developed — hydrodynamic and thermal, laminar and turbulent, for pipes and ducts — with the spread across the published correlations shown rather than hidden, because it is a disagreement about the word "developed" and not about the physics.
- Hydraulic Diameter CalculatorD_h = 4A/P for a round pipe, a rectangular or square duct, an annulus, parallel plates, a part-full pipe, a trapezoidal channel or any section you can measure — with the hydraulic radius beside it, a plain statement of which of the two your next formula wants, and the exact laminar friction constant for the section, because it is not 64/Re unless the section is round. For engineers setting up an internal-flow simulation or checking one.
- Minor Loss Coefficient CalculatorK factors turned into pressure drop, head loss and an equivalent length in diameters — with the sudden expansion and contraction derived rather than tabulated, the question of WHICH velocity the head belongs to answered explicitly, and the factor-of-two disagreement between published K tables shown as a range instead of hidden behind one number.
- Pipe Friction Factor & Pressure Drop CalculatorDarcy friction factor, pressure drop, head loss, wall shear stress and pumping power for a pipe, duct or annulus — with the friction factor chosen by measurement rather than reputation, the exact laminar constant for non-round sections, and an explicit refusal to give a single number in the transitional band. For engineers sizing a line or validating a CFD pressure drop.