Naked Science Forum
General Science => General Science => Topic started by: Atomic-S on 15/07/2007 05:25:35
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What is the formula for the flow rate (e.g., litres/sec) of a liquid in a pipe of a given length and diameter, having a given pressure difference between the ends?
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Poiseulle's formula
D = [(π.r4.d)/8.η].[(p1-p2)/l]
with
- π = pi (or 3.1416)
- D = flow rate in kg/sec
- r = radius of the pipe in m
- d = density in kg/m3
- η = dynamic viscosity in Ns/m2
- (p1- p2) = pressure difference in N/m2
- l = length in m
You'll find this formula in any advance handbook on physics or engineering. I copied it from "polytechnisch zakboekje", a Dutch pocketbook with all kinds of physical and chemical constants, formulae and other things useful for engineers.
I'm affraid it will require some converting to more traditional units.
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Thanx; I knew it depended steeply upon the diameter, but was not sure just how steeply.