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.

from math import *

from thermo.units import Stream

from fluids.units 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(f"Reynolds number = {Re}")
fd = friction_factor(Re=Re, eD=_roughness["Glass"]/Di)
print(f"Darcy friction factor = {fd}")

Reynolds number = 101022.58866016791 dimensionless
Darcy friction factor = 0.01810802221356977 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.