Pressure drop (ΔP)
Definition
The pressure difference needed to drive a flow through a channel. For laminar flow it is linear in flow rate (Hagen–Poiseuille).
Explanation
The pressure drop ΔP is the pressure a pump must supply to push a given flow rate through a channel against its hydraulic resistance.
For laminar flow in a circular channel it follows Hagen–Poiseuille, ΔP = 128µLQ/(πD⁴); the strong 1/D⁴ dependence means small channels demand large pressures.
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Further reading
- Flow, pressure & resistance cheat sheet — SemitreeVerify the current edition.