Water flows through a pipe of radius 0.025 m at 1.5m/s. What is the volume flow rate?

Water flows through a pipe of radius 0.025 m at 1.5m/s. What is the volume flow rate?

Solution

“Volume flow rate” = Volumetric Flowrate = VF

Volumetric Flowrate, m^3 /sec = Velocity, m/sec x Area, m^2

Let’s assume the radius is the internal pipe radius, otherwise we need to correct it for the pipe thickness.

Area = π x r^2 = 3.14 x ( 0.025 ) ^ 2 = 1.96 x 10^-3 m2

Velocity = 1.5 m / sec

VF, m^3 / sec = (1.5) x (1.96 x 10^ -3) = 2.95x 10^-3 m3/s

Volumetric Flowrate = 2.95x 10^-3 m3/sec

Let’s convert the units to something more recognizable… (to me at least)

1 cubic meter= 1 m3 = 1000 liter

therefore…

Volumetric Flowrate = 2.95 liter /sec

Let’s convert to English units of gallon per minute (gpm).

VF = 2.95 liter/sec x 1 gallon/3.79 liter x 60 sec/min = 46.6 gpm

The pipe diameter in inches is…

( 2 ) x ( 0.025 m ) x ( 39.37 in/m ) = 1.97 inch ID

47 gpm in a 2-inch pipe?

Yes, with enough pressure that is possible.