Pressure drop. Laminar flow, horizontal pipe
Pressure Drop Drawing and Equation:
Pressure Drop Equation Derivation
For steady flow of an incompressible fluid in a constant diameter horizontal pipe using the Darcy-Weisbach friction loss equation, the energy equation from location 1 to 2 is expressed in terms of pressure drop as:
When Re < 2100, flow is laminar and:
Then pressure drop is:
The final pressure drop equation is often called Poiseuille's law after the original researcher (Munson et al., 1998, p. 468).
Unit abbreviations, symbols: kg=kilogram, m=meter, N=Newton, s=second. A=Pipe area, f=Moody friction factor.
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