7.1 Smooth Pipe (Plastic)

Water at 30 degrees Celsius flows through a 20 m length of 50 mm plastic (smooth wall) pipe, at a flow rate of 200 L/min.

Calculate the Reynolds number and friction factor.

In [1]:
from fluids.units import  *
from thermo.units import Stream
from math import *

Q = 0.2*u.m**3/u.min
T = 30*u.degC
P = 2*u.bar # assumed
water = Stream('water', T=T, P=P, Q=Q)

NPS, Di, Do, t = nearest_pipe(Di=0.05*u.m)
v = Q/(pi/4*Di**2)
Re = Reynolds(D=Di, rho=water.rho, mu=water.mu, V=v)
print('Reynolds number = %s' %Re)
fd = friction_factor(Re=Re, eD=_roughness['Glass']/Di)
print('Darcy friction factor = %s' %fd)

Reynolds number = 101005.004737 dimensionless
Darcy friction factor = 0.0181086578522 dimensionless

The values presented in their solution are Re=100600; and fd=0.0179. The difference in values is due to the precision they used.