Engineering math problem?

Question

Does anyone know how to work that out?

calculate the maximum velocity of water that can flow in laminar form in a pipe 20m long and 60mm bore. Determine the pressure loss in this condition. The density is 1000 kg/m^3 and the dynamic viscocity is 0.001 N s/m^2 ???

Answer 1

Ok, in order to find the maximum velocity of water that can flow in laminar form, you have to get Reynolds number, where

Re=(density)(Velocity)(Diameter)/(dyna... viscosity)

you know that laminar flow will happen approximately until Re is 3000, so you use that number for Re. Solving for Velocity

Velocity=Re*Dynamic Viscosity/(density*Diameter)

so

V = 3000*0.001N*s/m^2/(1000kg/m^3*60mm)

V = 0.05 m/s

Now for the pressure loss you need the material of the pipe, so i can't give you an exact number. What i can give you is the equation.

lf=KV^2/2g

where lf is in m, g is the acceleration of gravity, v is velocity and k is the resistance quotient.

K = fL/D

where f is the friction property of the material, L is the length and D is the diameter.

Hope this helps.