Pipeline Hydraulics Calculator

Reynolds numbers below 2300 indicate laminar flow, where friction factor has a simple, exact closed-form solution (64/Re) because the fluid moves in smooth, parallel layers. Above that threshold flow becomes turbulent and friction no longer follows a simple ratio, so the calculator switches to the Swamee-Jain approximation, an explicit formula that closely matches the Colebrook equation used for turbulent pipe flow without requiring an iterative solve.

The calculator divides total pressure drop — friction loss plus elevation head — by an assumed maximum pump discharge pressure of 1,400 psi, then rounds up to the nearest whole station. A longer or higher-friction pipeline, a smaller diameter, or more uphill elevation change all increase total pressure drop and therefore increase the number of stations needed.

Friction loss is the pressure the fluid loses to viscous drag against the pipe wall over the entire length, computed from the Darcy-Weisbach equation, while elevation head is a separate, purely gravitational effect — climbing uphill adds pressure the pumps must overcome, and running downhill reduces it. The calculator adds these two independent contributors together to get total pressure drop, since a line can lose pressure to friction even on flat ground, or gain help from downhill elevation even with minimal friction.

Pump horsepower is calculated from flow rate, converted to gallons per minute, multiplied by the pressure each station must add, then divided by a constant (1714) and an assumed 85% pump efficiency. Because both flow rate and total pressure drop — which itself depends on velocity squared through the friction term — increase with throughput, horsepower requirements grow faster than linearly as you push more oil through the same pipe.