Caída de presión en tubería

Cómo se calcula

• Liquid: ΔP = f·(L/D)·ρv²/2 with f from an iterated Colebrook–White solution, plus the elevation head.
• Gas: Weymouth, Panhandle A and Panhandle B, each solved for the outlet pressure from the squared-pressure form, with z at the average line pressure.
• Standard conditions are 60 °F and 14.73 psia; length is converted to miles internally because that is what the gas equations are written in.
• The API RP 14E erosional velocity limit is reported for the gas case so the rate can be checked against it.

Dónde deja de ser cierto

Single phase, isothermal, and — for gas — no elevation profile. Real gathering lines carry liquid, and a two-phase line with holdup in its low points can have several times this pressure drop, arriving in slugs the steady-state number cannot describe. The gas equations also assume fully turbulent flow and hide everything they do not model inside an efficiency factor, which is why three of them are shown: when Weymouth and Panhandle B disagree by twenty per cent, that disagreement is the honest uncertainty, not a reason to pick the convenient one.